EP2632634B1 - Clamping device for a hand-held machine tool - Google Patents

Description

State of the art

From the DE 38 24 040 C1 , which forms the basis for the preamble of claim 1, a handheld power tool clamping device is already known which comprises a fastening unit for securing a tool in the axial direction on a spindle and a decoupling unit for decoupling a fastening element of the fastening unit in the axial direction.

Disclosure of the invention

The invention is based on a handheld power tool clamping device, in particular for angle grinders, with at least one fastening unit for securing a tool in the axial direction on a spindle and with at least one decoupling unit for decoupling at least one fastening element of the fastening unit in the axial direction.

It is proposed that the hand-held power tool clamping device comprises a flow safety unit which, in order to prevent the fastening unit and / or the tool from running off the spindle during braking, is provided to at least partially convert a first relative movement between at least two fastening elements of the fastening unit into a second relative movement . In this context, “provided” should be understood to mean in particular specially equipped and / or specially designed. A “fastening unit” is to be understood here in particular as a unit which is provided to secure the tool on a spindle by means of a form fit and / or a force fit and / or to be braced against a further component, in particular a receiving flange of a handheld power tool, so that forces and / or torques can be transmitted from the spindle to the tool in a mounted state of the tool. The fastening unit preferably has at least one first fastening element which rests on the tool by screwing a second fastening element of the fastening unit to the spindle and which is movable relative to the second fastening element. The second fastening element particularly preferably has a thread for screwing to a thread of the spindle, so that the fastening unit can be screwed onto the spindle to secure and / or clamp the tool.

The term “axial direction” is intended here to define in particular a direction which runs at least substantially parallel to a central axis of the fastening unit. The fastening unit is particularly preferably designed to be rotationally symmetrical to the central axis. Furthermore, in an assembled state of the fastening unit, the central axis runs in particular coaxially to an axis of rotation of the spindle. "Essentially parallel" is to be understood here to mean in particular an alignment of a direction relative to a reference direction, in particular in a plane, the direction having a deviation from the reference direction, in particular less than 8 °, advantageously less than 5 ° and particularly advantageously less than 2 °. A "decoupling unit" is to be understood here in particular as a unit which is provided to apply an axial clamping force acting by the fastening unit in an assembled state on the tool for dismantling the fastening unit by at least 5%, preferably at least 50% and particularly preferably at least to reduce by 90%. Particularly preferably, the first fastening element can move relative to the first fastening element along the axial direction by means of decoupling by the decoupling unit, in particular in the direction of the first fastening element. The fastening unit is particularly preferably detachably coupled to the spindle. "Removable" is to be understood here in particular as a decoupling of the fastening unit from the spindle, a functionality of the fastening unit, in particular a function for converting the first relative movement between the first fastening element and the second fastening element into the second relative movement, being retained in a decoupled state .

A "flow safety unit" is to be understood here in particular as a unit which is provided to prevent a clamping force of the fastening unit in the axial direction from being canceled in a braking operation. A "braking operation" is to be understood here in particular as an operation of a hand-held power tool, in particular a spindle of the hand-held power tool, in which the spindle is braked by means of a braking device, so that the spindle continues to run, for example when a power supply to an electric motor is interrupted, can advantageously be at least largely prevented. During the braking operation, moments of inertia of the tool, in particular a disk-shaped tool, can lead to a relative movement between the tool fastened on the spindle and the fastening unit. The relative movement between the tool and the fastening unit can lead to the fastening unit being released and thus being able to run off the spindle. The flow safety unit is particularly preferably provided to increase a clamping force as a result of a relative movement between the at least two transmission elements in braking operation by at least 2%, preferably by at least 20% and particularly preferably by at least 50%. Particularly preferably, the first fastening element is moved relative to the second fastening element in the axial direction in order to increase the clamping force, in particular in the direction of the tool. By means of the hand-held power tool clamping device according to the invention, the fastening unit can advantageously be prevented from running off the spindle and thus loosening the tool from the spindle.

It is further proposed that the flow safety unit have at least one reset unit which is provided to automatically reset at least one of the two fastening elements into a basic position. In a relieved state, the first fastening element and / or the second fastening element is preferably reset automatically into the basic position by means of the reset unit. The term "automatically" is intended to define in particular an automated resetting of the actuating element by the resetting unit, in particular a resetting decoupled from a direct and / or indirect force of an operator on the first fastening element and / or the second fastening element. A high level of operating convenience of the handheld power tool clamping device can advantageously be achieved. Furthermore, it can advantageously be ensured by means of the reset unit that the first fastening element and / or the second fastening element is reliably returned to the basic position, so that reliable functioning of the safety valve unit can be guaranteed.

The flow safety unit is preferably designed as a lifting unit, which is provided to move the fastening elements, in particular the at least two fastening elements movable relative to one another, as a result of the first relative movement relative to one another along the axial direction. The first fastening element is particularly preferably moved relative to the second fastening element along the axial direction as a result of the first relative movement. Here, the first relative movement between the first fastening element and the second fastening element is a rotary movement. A “lifting unit” is to be understood here in particular as a unit which comprises at least two components which correspond to one another and by means of which a movement of an element, in particular the first fastening element, can be generated along a straight path. However, it is also conceivable that the flow safety unit for generating a relative movement between the first fastening element and the second fastening element is designed in another configuration that appears sensible to a person skilled in the art, such as a cam gear, etc. By means of the configuration according to the invention, an axial stroke of the first fastening element relative to the second fastening element can advantageously be generated.

It is further proposed that the lifting unit has at least one lifting element which is at least partially formed in one piece with one of the fastening elements. "In one piece" is to be understood in particular to be at least cohesively connected, for example by a welding process, an adhesive process, an injection molding process and / or another process that appears sensible to a person skilled in the art, and / or advantageously formed in one piece, such as by a Production from a single casting and / or by production in a single or multi-component injection molding process and advantageously from a single blank. Installation space, assembly effort and costs can advantageously be saved.

The lifting element is advantageously designed in the shape of a ramp. "Ramp-shaped" is to be understood here in particular as a geometric shape that has a mathematically defined gradient along a route 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 and / or the starting point is in a plane is arranged, which runs at least substantially parallel to a plane in which the end point is arranged. The lifting unit advantageously has at least one second lifting element which, as a result of the first relative movement, generates the second relative movement by interacting with the first lifting element. Here, the second lifting element is preferably designed in the shape of a ramp, so that by means of a rotation of the first fastening element relative to the second fastening element, the first ramp-shaped lifting element can slide along the second ramp-shaped lifting element. However, it is also conceivable that the second lifting element is designed as a rolling element and can roll on the first ramp-shaped lifting element. A pitch of the first lifting element and / or of the second lifting element is preferably equal to or greater than a pitch of a thread of the fastening unit and the spindle onto which the fastening unit can be screwed on and off. The pitch of the first lifting element and / or the second lifting element corresponds in particular to 100 to 150% of the pitch of the thread of the fastening unit and the spindle, preferably 110 to 140% of the pitch of the thread of the fastening unit and the spindle and particularly preferably 120 to 130% of the Pitch of the thread of the fastening unit and the spindle. To increase 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 agents are introduced into the thread of the fastening unit and the spindle, such as rubber elements, spring elements, coatings, etc. This can be structurally simple the first relative movement can be converted into the second relative movement. Furthermore, by means of the ramp-shaped lifting element, a high clamping force can advantageously be generated during braking operation, which acts on the tool to tighten it.

Furthermore, it is proposed that the lifting unit has at least one lifting element which is movably mounted relative to the at least two fastening elements which are movable relative to one another. Constructively, it can be a simple one Relative movement between the first fastening element and / or the second fastening element and the lifting element can be generated to avoid the fastening unit and / or the tool from running off the spindle.

In a preferred embodiment of the handheld power tool clamping device, the lifting element is at least partially arranged between the fastening elements. The term “between” is intended here to define, in particular, a spatial arrangement. The lifting element is preferably arranged between the first fastening element and the second fastening element along the axial direction. In an alternative embodiment of the handheld power tool clamping device according to the invention, the lifting element is arranged along a direction perpendicular to the axial direction between the first fastening element and the second fastening element. A compact handheld power tool clamping device can advantageously be achieved.

The lifting element is preferably guided at least partially in ring tracks of the at least two fastening elements that are movable relative to one another. A "ring track" is to be understood here in particular as at least one track that extends through 360 ° along a circumferential direction, the track being designed in particular as a groove. Particularly preferably, the ring tracks each run in a thread-like manner along the circumferential direction of the sides of the at least two fastening elements that are movable relative to one another, facing inwards. Here, the thread-like ring tracks have a mathematically defined gradient in the axial direction, so that a movement of the lifting element in the ring tracks causes a stroke movement along the axial direction. The circumferential direction here extends in a plane that is essentially perpendicular to the axial direction. A pitch of the ring track of the first fastening element and the ring track of the second fastening element corresponds in particular to 100 to 150% of the pitch of the thread of the fastening unit and the spindle, preferably 110 to 140% of the pitch of the thread of the fastening unit and the spindle and particularly preferably 120 to 130 % of the pitch of the thread of the fastening unit and the spindle. By guiding the lifting element in an annular path of the first fastening element and in an annular path of the second fastening element, it is advantageous to couple the first fastening element and the second fastening element can be achieved by means of the lifting element. The lifting element can be guided in a structurally simple manner.

The lifting element is advantageously formed by at least one rolling element. The lifting element is particularly preferably formed by a multiplicity of rolling elements which are movably supported in a rolling element cage. As a result, the first relative movement between the first fastening element and the second fastening element can advantageously be converted into the second relative movement with little friction. A long service life of the hand-held power tool clamping device can thus also be achieved.

It is also proposed that the flow safety unit and the decoupling safety unit have at least one common lifting element. In this way, a compact handheld power tool clamping device can be achieved in a particularly advantageous manner.

The invention is also based on a handheld power tool, in particular an angle grinder, with a handheld power tool clamping device according to the invention. A high level of operating comfort for an operator of the hand-held power tool can advantageously be achieved. Furthermore, a tool can advantageously be prevented from running off the spindle of the hand-held power tool.

drawing

Further advantages emerge from the following description of the drawings. Exemplary embodiments of the invention are shown in the drawing. The drawing, the description and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations.

Fig. 1

eine erfindungsgemäße Handwerkzeugmaschine mit einer erfindungsgemäßen Handwerkzeugmaschinenspannvorrichtung in einer schematischen Darstellung,

Fig. 2

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

Fig. 3

eine Detailansicht der erfindungsgemäßen Handwerkzeugmaschinenspannvorrichtung in einer schematischen Darstellung

Fig. 4

eine weitere Detailansicht der erfindungsgemäßen Handwerkzeugmaschinenspannvorrichtung in einer schematischen Darstellung,

Fig. 5

eine Schnittansicht entlang der Linie V-V aus Figur 4 der erfindungsgemäßen Handwerkzeugmaschinenspannvorrichtung in einer schematischen Darstellung,

Fig. 6

eine Detailansicht einer alternativen Ausführung der erfindungsgemäßen Handwerkzeugmaschinenspannvorrichtung in einer schematischen Darstellung,

Fig. 7

eine weitere Detailansicht der alternativen Ausführung der erfindungsgemäßen Handwerkzeugmaschinenspannvorrichtung in einer schematischen Darstellung,

Fig. 8

eine Schnittansicht entlang der Linie VIII-VIII aus Figur 7 der erfindungsgemäßen Handwerkzeugmaschinenspannvorrichtung und

Fig. 9

eine Detailansicht einer weiteren alternativen Ausführung der erfindungsgemäßen Handwerkzeugmaschinenspannvorrichtung in einer schematischen Darstellung.

Show it:

Fig. 1

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

Fig. 2

a detailed view of a spindle of the hand machine tool Figure 1 with the handheld power tool clamping device according to the invention arranged on the spindle in a schematic representation,

Fig. 3

a detailed view of the handheld power tool clamping device according to the invention in a schematic representation

Fig. 4

a further detailed view of the handheld power tool clamping device according to the invention in a schematic representation,

Fig. 5

a sectional view along the line VV Figure 4 the handheld power tool clamping device according to the invention in a schematic representation,

Fig. 6

a detailed view of an alternative embodiment of the handheld power tool clamping device according to the invention in a schematic representation,

Fig. 7

a further detailed view of the alternative embodiment of the handheld power tool clamping device according to the invention in a schematic representation,

Fig. 8

a sectional view along the line VIII-VIII Figure 7 the handheld power tool clamping device according to the invention and

Fig. 9

a detailed view of a further alternative embodiment of the handheld power tool clamping device according to the invention in a schematic representation.

Description of the exemplary embodiments

Figure 1 shows a handheld power tool 46a designed as an angle grinder 44a with a handheld power tool clamping device 10a according to the invention in a schematic representation. The angle grinder 44a comprises a protective hood unit 48a, a handheld power tool housing 50a and a main handle 52a, which extends on a side 54a of the handheld power tool housing 50a facing away from a tool 14a in the direction of a main extension direction 56a of the angle grinder 44a. The tool 14a is designed as a grinding wheel. However, it is also conceivable that the tool 14a is designed as a separating or polishing disk. The hand-held power tool housing 50a comprises a motor housing 58a for accommodating an electric motor (not shown in detail here) and a gear housing 60a for accommodating a gearbox (not shown in detail here). An additional handle 62a is arranged on the gear housing 60a. The additional handle 62a extends transversely to the main direction of extent 56a of the angle grinder 44a.

Figure 2 shows the hand-held power tool clamping device 10a arranged on a spindle 18a of the angle grinder 44a. The spindle 18a extends perpendicular to the main direction of extent 58a out of the gear housing 62a (in Figure 2 not shown). The spindle 18a has two flattened areas 64a on an outer circumference for receiving a receiving flange 70a, which are arranged diametrically and thus form a 2-sided 66a. Here is in Figure 2 only one of the flats 64a is shown. The receiving flange 70a has a recess corresponding to the 2-edge 66a (not shown in more detail here), in which the 2-edge 66a engages when the receiving flange 70a is in an assembled state. Thus, the receiving flange 70a is non-rotatably connected to the spindle 18a by means of the 2-edge 66a. In an assembled state, the receiving flange 70a is arranged on a side of the spindle 18a facing the angle grinder 44a. The spindle 18a is rotatably driven about an axis of rotation 68a of the spindle 18a by means of the transmission and the electric motor of the angle grinder 44a. In an operating mode of the angle grinder 44a, the spindle 18a is driven to rotate in a clockwise direction as viewed from the angle grinder 44a. This is where the handheld power tool clamping device 10a also driven to rotate in a clockwise direction in an assembled state. The handheld power tool clamping device 10a comprises a fastening unit 12a for securing the tool 14a in the axial direction 16a on the spindle 18a. The fastening unit 12a braces the tool 14a against the receiving flange 70a which is positively connected to the spindle 18a.

When the tool 14a is assembled, the tool 14a is pushed onto the spindle 18a with a central opening along the axial direction 16a until the tool 14a rests against a contact surface of the receiving flange 70a already attached to the spindle 18a. The hand-held power tool clamping device 10a is then screwed onto an external thread 72a of the spindle 18a by means of the fastening unit 12a. The fastening unit 12a comprises a first fastening element 22a, which has a contact surface 76a for resting on a side of the tool 14a facing away from the receiving flange 70a. The contact surface 76a of the first fastening element 22a and the side of the tool 14a contacting the contact surface 76a have an adhesive coating (not shown in detail here) so that there is high friction between the contact surface 76a of the first fastening element 22a and the side contacting the contact surface 76a of the tool 14a can be reached. However, it is also conceivable that the contact surface 76a and the side of the tool 14a that is in contact with the contact surface 76a have a corresponding, ramp-like geometry which engage one another. Other friction-increasing measures and configurations of the contact surface 76a and of the side of the tool 14a resting on the contact surface 76a that appear sensible to a person skilled in the art are also conceivable. Furthermore, the fastening unit 12a comprises a second fastening element 28a, which has an internal thread 74a for screwing to the external thread 72a of the spindle 18a. The tool 14a is clamped to the receiving flange 70a by screwing the fastening unit 12a onto the spindle 18a. By clamping the tool 14a on the receiving flange 70a, a torque can be transmitted from the spindle 18a to the tool 14a. In the working mode of the angle grinder 44a, the tool 14a is driven to rotate in a clockwise direction, viewed from the angle grinder 44a. In the operating mode of the angle grinder 44a, a clamping force is maintained by means of an interaction of the external thread 72a of the spindle 18a, the internal thread 74a of the second fastening element 28a and frictional forces between the contact surface 76a and the side of the tool 14a resting on the contact surface 76a.

For screwing the second fastening element 28a to the spindle 18a, the fastening unit 12a also has an actuating element 78a. The actuating element 78a is annular ( Figure 3 ). Furthermore, the actuating element 78a has coupling regions 80a, 82a which are designed in the shape of a web. The coupling regions 80a, 82a here extend along a radial direction 114a running perpendicular to a central axis 24a of the actuating element 78a in the direction of the second fastening element 28a. The second fastening element 28a also has coupling areas 84a, 86a for the rotationally fixed coupling to the actuating element 78a. The coupling regions 84a, 86a of the second fastening element 28a extend along the radial direction 114a in the direction of the actuating element 22a. A number of the coupling regions 84a, 86a of the second fastening element 28a is dependent on a number of the coupling regions 80a, 82a of the actuating element 78a. Overall, the actuating element 78a has two coupling areas 80a, 82a and the fastening element 28a also has two coupling areas 84a, 86a. However, it is also conceivable that the actuating element 78a and the fastening element 28a each have a different number of coupling areas 80a, 82a, 84a, 86a that would appear reasonable to a person skilled in the art ( Figure 4 ).

Furthermore, the hand-held power tool clamping device 10a comprises a decoupling unit 20a for decoupling the first fastening element 22a of the fastening unit 12a in the axial direction 16a. A clamping force of the fastening unit 12a can be reduced by means of the decoupling unit 20a, so that the fastening unit 12a can be unscrewed from the spindle 18a by an operator without tools. The second fastening element 28a is arranged within the annular actuating element 78a ( Figures 4 and 6th ). To connect the actuating element 78a and the second fastening element 28a, the actuating element 78a and the second fastening element 28a each have a groove 120a, 122a in which an O-ring 124a of the fastening unit 12a is arranged. The actuating element 78a surrounds the second fastening element 28a along a circumferential direction 88a. The first fastener 22a is essentially disk-shaped and is also arranged within the actuating element 78a. To connect the actuating element 78a and the first fastening element 22a, the actuating element 78a and the second fastening element 28a each have a groove 128a, 130a in which an O-ring 126a of the fastening unit 12a is arranged. The first fastening element 22a has a ramp-shaped lifting element 34a ( Figure 5 ). The lifting element 34a is formed in one piece with the first fastening element 22a. Overall, the first fastening element 22a has two lifting elements 34a formed in one piece with the fastening element 22a, only one of the lifting elements 34a being shown in the figures. The lifting elements 34a are arranged offset from one another by approximately 180 ° along the circumferential direction 88a. The second fastening element 28a also has two lifting elements 90a which are embodied in one piece with the second fastening element 28a. The lifting elements 90a of the second fastening element 28a are arranged offset from one another by approximately 180 ° along the circumferential direction 88a. In the figures, only one of the lifting elements 90a of the second fastening element 28a is shown. The lifting elements 34a of the first fastening element 22a have a slope opposite to the lifting elements 90a of the second fastening element 28a ( Figure 5 ).

The decoupling unit 20a further comprises two lifting elements 36a, 92a which effectively couple the first fastening element 22a and the second fastening element 28a to one another. The lifting elements 36a, 92a of the decoupling unit 20a are designed in the shape of a ramp. Furthermore, the lifting elements 36a, 92a of the decoupling unit 20a are arranged between the first fastening element 22a and the second fastening element 28a of the fastening unit 12a. Here, the lifting elements 36a, 92a of the decoupling unit 20a have a slope opposite to the lifting elements 34a of the first fastening element 22a on a side facing the lifting elements 34a of the first fastening element 22a. Furthermore, the lifting elements 36a, 92a of the decoupling unit 20a on a side facing the lifting elements 90a of the second fastening element 28a have an incline opposite to the lifting elements 90a of the second fastening element 28a ( Figure 5 ). The lifting elements 36a, 92a of the decoupling unit 20a are movably supported relative to the first fastening element 22a and relative to the second fastening element 28a in the fastening unit 12a. Here are the lifting elements 36a, 92a of the decoupling unit 20a to the lifting elements 34a of the first fastening element 22a and to the lifting elements 90a of the second fastening element 28a. Furthermore, the decoupling unit 20a comprises locking elements 94a, 96a, which prevent a movement of the lifting elements 36a, 92a of the decoupling unit 20a along the circumferential direction 88a. The locking elements 94a, 96a are designed as cylindrical rollers. However, it is also conceivable that the blocking elements 94a, 96a are designed in a different shape that appears sensible to a person skilled in the art.

Furthermore, the decoupling unit 20a has four spring elements 98a, 100a, 102a, 104a, which are provided to pretension the first fastening element 22a and the second fastening element 28a against one another along the circumferential direction 88a. Two of the spring elements 98a, 100a, 102a, 104a are each arranged along the circumferential direction 88a between one of the coupling areas 80a, 82a of the actuating element 78a and one of two web-shaped coupling areas 106a, 108a of the first fastening element 22a. The other two of the spring elements 98a, 100a, 102a, 104a are also each arranged between one of the coupling areas 106a, 108a of the first fastening element 22a and one of two delimiting elements 162a, 164a of the second fastening element 28a along the circumferential direction 88a (FIG. 4). The spring elements 98a, 100a, 102a, 104a are designed as compression springs. However, it is also conceivable for the spring elements 98a, 100a, 102a, 104a to be designed in a different manner that appears sensible to a person skilled in the art.

When the fastening unit 12a is screwed on, a force exerted by an operator on the actuating element 78a is transmitted to the coupling regions 84a, 86a of the second fastening element 28a by means of the coupling regions 80a, 82a of the actuating element 78a. The fastening unit 12a is thus screwed onto the spindle 18a by the interaction of the internal thread 74a of the second fastening element 28a and the external thread 72a of the spindle 18a. When the fastening unit 12a is loosened and / or unscrewed from the spindle 18a, a force is also applied to the actuating element 78a by an operator. However, this force has a direction opposite to the force exerted when unscrewing. When the actuating element 78a is actuated for loosening and / or unscrewing of the fastening unit 12a, the actuating element 78a is first rotated relative to the first fastening element 22a and relative to the second fastening element 28a. The coupling areas 80a, 82a of the actuating element 78 are here moved away from the coupling areas 84a, 86a of the second fastening element 28a along the circumferential direction 88a. The spring elements 98a, 100a, 102a, 104a are compressed here. The actuating element 78a also has two decoupling recesses 110a, 112a. The decoupling recesses 110a, 112a are arranged offset from one another by approximately 180 ° along the circumferential direction. Another number of decoupling recesses 110a, 112a that appears sensible to a person skilled in the art is also conceivable. By rotating the actuating element 78a, the decoupling recesses 110a, 112a are rotated into a decoupling position, so that the locking elements 94a, 96a can move into the decoupling recesses 110a, 112a to enable the lifting elements 36a, 92a of the decoupling unit 20a to move along the radial direction 114a.

As a result of the movement of the locking elements 94a, 96a, the lifting elements 36a, 92a of the decoupling unit 20a can move along the circumferential direction 88a. The lifting elements 36a, 92a of the decoupling unit 20a slide on the lifting elements 34a of the first fastening element 22a and the lifting elements 90a of the second fastening element 28a. As a result of the sliding of the lifting elements 36a, 92a of the decoupling unit 20a, the first fastening element 22a moves along the axial direction 16a relative to the second fastening element 28a in the direction of the second fastening element 28a. This reduces a clamping force between the internal thread 74a of the second fastening element 28a and the external thread 72a of the spindle 18a. As a result, the operator can unscrew the fastening unit 12a from the spindle 18a without tools.

The angle grinder 44a further comprises a braking device (not shown in more detail here) to prevent the spindle 18a from slowing down when the angle grinder 44a is switched off as a result of an interruption in a power supply. During the shutdown process, the angle grinder 44a switches to a braking mode and brakes the spindle 18a by means of the braking device. In the braking mode, the tool 14a continues to move as a result of inertia around the axis of rotation 68a of the spindle 18a, so that a torque difference arises between the tool 14a, the spindle 18a and the fastening unit 12a. This torque difference leads to a relative movement between the tool 14a and the fastening unit 12a. A clamping force can be canceled due to friction between the fastening unit 12a and the inert tool 14a. As a result, the fastening unit 12a can detach itself from the spindle 18a and the fastening unit 12a can run off the spindle 18a together with the tool 14a.

To prevent the fastening unit 12a and / or the tool 14a from running off during braking, the hand-held power tool clamping device 10a has a run-off safety unit 26a, which is provided to at least partially convert a first relative movement between the first fastening element 22a and the second fastening element 28a of the fastening unit 12a transfer second relative movement. Here, the first relative movement between the first fastening element 22a and the second fastening element 28a is a rotation about the axis of rotation 68a. The second relative movement between the first fastening element 22a and the second fastening element 28a is a translation along the axial direction 16a. The rotation between the first fastening element 22a and the second fastening element 28a arises during braking operation from the torque difference between the tool 14a and the fastening unit 12a. The tool 14a rotates along with the first fastening element 22a due to the resulting friction between the tool 14a and the contact surface 76a of the first fastening element 22a.

The safety valve unit 26a has a reset unit 30a which is provided to automatically reset the first fastening element 22a and the second fastening element 28a into a basic position. The resetting unit 30a here comprises the spring elements 98a, 100a, 102a, 104a of the decoupling unit 20a for resetting. The spring elements 98a, 100a, 102a, 104a rotate the first fastening element 22a, the second fastening element 28a and the actuating element 78a relative to one another along the circumferential direction 88a in a substantially unloaded state of the fastening unit 12a. As a result, the blocking elements 94a, 96a of the decoupling unit 20a are moved out of the decoupling recesses 110a, 112a. The blocking elements 94a, 96a here exert a force on the lifting elements 36a, 92a of the decoupling unit 20a. The lifting elements 36a, 92a of the decoupling unit 20a are thus moved between the lifting elements 34a of the first fastening element 22a and the lifting elements 90a of the second fastening element 28a. A movement of the lifting elements 36a, 92a of the decoupling unit 20a in the direction of the locking elements 94a, 96a is prevented by means of an interaction of the locking elements 94a, 96a of the decoupling unit 20a and the coupling areas 84a, 86a of the second fastening element 28a. The decoupling recesses 110a, 112a each have an inclined surface 116a, 118a, which is provided to exert a force component in the direction of the lifting elements 36a, 92a of the decoupling unit 20a on the blocking elements 94a, 96a as a result of a rotary movement of the actuating element 78a.

The safety valve unit 26a is designed as a lifting unit 32a, which is provided to move the first fastening element 22a as a result of the first relative movement relative to the second fastening element 28a along the axial direction 16a. The lifting unit 32a comprises the lifting elements 34a, which are formed in one piece with the first fastening element 22a. Furthermore, the lifting unit 32a comprises the lifting elements 90a, which are formed in one piece with the second fastening element 28a. The lifting unit 32a also has the lifting elements 36a, 92a of the decoupling unit 20a, which are movably mounted relative to the first fastening element 22a and relative to the second fastening element 28a. The flow safety unit 26a and the decoupling unit 20a thus have two common lifting elements 36a, 92a.

In a braking operation of the angle grinder 44a, the first fastening element 22a is rotated relative to the second fastening element 28a along the circumferential direction 88a as a result of friction and a torque difference between the tool 14a and the first fastening element 22a. The first fastening element 22a is moved against a spring force of the spring elements 98a, 100a, which are arranged between the coupling regions 106a, 108a of the first fastening element 22a and the limiting elements 162a, 164a of the second fastening element 28a. The locking elements 94a, 96a prevent a movement of the lifting elements 36a, 92a of the lifting unit 32a, so that the lifting elements 34a of the first fastening element 22a can slide on the lifting elements 36a, 92a of the lifting unit 32a. The first fastening element 22a is moved as a result of the slope of the lifting elements 34a of the first fastening element 22a relative to the second fastening element 28a along the axial direction 16a in the direction of the tool 14a. A clamping force acting on the tool 14a can be maintained or increased, so that the fastening unit and / or the tool 14a can be prevented from running off the spindle 18a. To loosen and / or unscrew the fastening unit 12a, the actuating element 78a is actuated by the operator. As already described above, this reduces a clamping force, so that an operator can easily loosen the fastening unit.

The hand-held power tool clamping device 10a further comprises a friction-reducing element which is arranged in the fastening unit 12a. In this way, internal, prevailing frictional forces can be kept low. The friction-reducing element can be introduced into the fastening unit 12a in the liquid state or the friction-reducing element is applied as coatings, such as Teflon coatings, to components of the fastening unit 12a that are movably mounted relative to one another.

In Figures 6 to 9 two alternative embodiments are shown. Components, features and functions that are essentially the same are generally numbered with the same reference symbols. To distinguish the exemplary embodiments, the letters a to c are added to the reference numerals of the exemplary embodiments. The following description is essentially limited to the differences from the first exemplary embodiment in FIG Figures 1 to 5 , with respect to the same components, features and functions to the description of the first embodiment in the Figures 1 to 5 can be referenced.

Figure 6 shows an alternative handheld power tool clamping device 10b with a fastening unit 12b for securing a tool 14b in the axial direction 16b on a spindle 18b of a handheld power tool 46b designed as an angle grinder 44b. The angle grinder 44b here has one to the in Figure 1 shown angle grinder 44a has an analogous structure. The handheld power tool clamping device 10b also has a decoupling unit 20b for a decoupling of a first fastening element 22b of the fastening unit 12b in the axial direction 16b ( Figure 7 ). The decoupling unit 20b has three lifting elements 132b, 134b, 136b ( Figure 8 ). The three lifting elements 132b, 134b, 136b are movably supported along a radial direction 114b. The decoupling unit 20b also has three locking elements 94b, 96b, 138b, which are provided to essentially prevent movement of the three lifting elements 132b, 134b, 136b in at least one operating position in the radial direction 114b. By rotating an actuating element 78b of fastening unit 12b about a central axis 24b of fastening unit 12b, movement of three locking elements 94b, 96b, 138b along radial direction 114b into one of three decoupling recesses 110b, 112b, 140b is made possible. If the three locking elements 94b, 96b, 138b are each in one of the three decoupling recesses 110b, 112b, 140b, then the lifting elements 132b, 134b, 136b of the decoupling unit 20b can execute a movement in the radial direction 114b. After a movement of the lifting elements 132b, 134b, 136b of the decoupling unit 20b, the first fastening element 22b can move in the radial direction 114b relative to the second fastening element 28b. The movement of the lifting elements 132b, 134b, 136b of the decoupling unit 20b in the radial direction 114b and the movement of the first fastening element 22b along the axial direction 16b have the consequence that a clamping force of an internal thread 74b of a second fastening element 28b and an external thread 72b of the spindle 18b is reduced. An operator can thus detach the fastening unit 12b from the spindle 18b without tools.

Furthermore, the hand-held power tool clamping device 10b has a flow safety unit 26b, which is provided to prevent the fastening unit 12b and / or the tool 14b from running off the spindle 18b during braking, at least partially a first relative movement between the first fastening element 22b and a second fastening element 28b of the fastening unit 12b to be converted into a second relative movement. The flow safety unit 26b comprises a reset unit 30b, which is provided to automatically reset the first fastening element 22b into a basic position. The reset unit 30b here has a spring element 142b. The spring element 142b is designed as a wire spring. One end of the spring element 142b is connected to the first fastening element 22b. An opposite end connected to the first fastening element 22b The end of the spring element 142b is connected to a carrier element 144b of the safety valve unit 26b. The spring element 142b thus brings about a return of the first fastening element 22b relative to the carrier element 144b.

The safety valve unit 26b is designed as a lifting unit 32b, which is provided to move the first fastening element 22b as a result of the first relative movement relative to the second fastening element 28b along the axial direction 16b. The lifting unit 32b has four lifting elements 34b, 90b (two shown in FIG. 7) which are formed in one piece with the first fastening element 22b. Furthermore, the lifting unit has four further lifting elements 36b, 92b, 158b, 160b, which are formed in one piece with the carrier element 144b. The carrier element 144b is formed along the axial direction 16b between the first fastening element 22b and the second fastening element 28b. Furthermore, the carrier element 144b is mounted movably relative to the first fastening element 22b and relative to the second fastening element 28b. Thus, the further lifting elements 36b, 92b, 158b, 160b of the carrier element 144b are also movably supported relative to the first fastening element 22b and relative to the second fastening element 28b. The lifting elements 34b, 90b of the first fastening element 22b and the lifting elements 36b, 92b, 158b, 160b of the carrier element 144b are each designed in the shape of a ramp. Here, the lifting elements 34b, 90b of the first fastening element 22b have an incline opposite to the lifting elements 36b, 92b, 158b, 160b of the carrier element 144b. The carrier element 144b is connected to the second fastening element 28b by means of a friction-increasing element 156b. In this way, a relative movement of the first fastening element 22b relative to the carrier element 144b can be ensured in a braking operation.

Figure 9 shows a further alternative handheld power tool clamping device 10c, which comprises a fastening unit 12c for securing a tool 14c in the axial direction 16c on a spindle 18c and a decoupling unit 20c for decoupling a first fastening element 22c of the fastening unit 12c in the axial direction 16c. The decoupling unit 20c has a structure analogous to the decoupling unit 20b, so that with regard to a mode of operation the decoupling unit 20c to the description of Figures 6 to 8 is referred.

Furthermore, the hand-held power tool clamping device 10c has a flow safety unit 26c, which is provided to prevent the fastening unit 12c and / or the tool 14c from running off the spindle 18c during braking, at least partially a first relative movement between the first fastening element 22c and a second fastening element 28c to convert the fastening unit 12c into a second relative movement. The flow safety unit 26c comprises a reset unit 30c, which is provided to automatically reset the first fastening element 22c into a basic position. Furthermore, the safety valve unit 26c is designed as a lifting unit 32c, which is provided to move the first fastening element 22c as a result of the first relative movement relative to the second fastening element along the axial direction 16c. The lifting unit 32c in this case has a lifting element 36c which is mounted movably relative to the first fastening element 22c and relative to the second fastening element 28c. The lifting element 36c is guided in an annular path 38c of the first fastening element 22c and in an annular path 40c of the second fastening element 28c. Furthermore, the lifting element 36c is formed as a rolling element 42c. The rolling element 42c comprises a cage 146c and a plurality of balls 148c, 150c, 152c 154c, which are mounted in the cage 146c. The rolling element 42 is arranged along a radial direction 114c, which runs perpendicular to the axial direction 16c, between the first fastening element 22c and the second fastening element 28c.

Claims (11)

1. Portable-power-tool clamping device having at least one fastening unit (12; 12b; 12c) for securing a tool (14a; 14b; 14c) in an axial direction (16a; 16b; 16c) on a spindle (18a; 18b; 18c) and having at least one uncoupling unit (20a; 20b; 20c) for uncoupling at least one fastening element (20a; 20b; 20c) of the fastening unit (12a; 12b; 12c) in the axial direction (16a; 16b; 16c),
   characterized by a run-off securing unit (26a; 26b; 26c), which, in order to avoid the fastening unit (12; 12b; 12c) and/or the tool (14a; 14b; 14c) running off the spindle (18a; 18b; 18c) during braking operation, is provided at least partially to convert a first relative movement, forming a rotary movement, between at least two fastening elements (22a, 28a; 22b, 28b; 22c, 28c) of the fastening unit (12a; 12b; 12c) into a second relative movement such that the first fastening element, as a result of the first relative movement, is moved relative to the second fastening element in the axial direction, wherein the first fastening element bears on the spindle by way of a screw connection of a first fastening element of the fastening unit and is movable relative to the second fastening element.
2. Portable-power-tool clamping device according to Claim 1,
   characterized in that the run-off securing unit (26a; 26b; 26c) has at least one restoring unit (30a; 30b; 30c), which is provided to reset at least one of the two fastening elements (22a, 28a; 22b, 28b; 22c, 28c) automatically into a starting position.
3. Portable-power-tool clamping device according to either of the preceding claims,
   characterized in that the run-off securing unit (26a; 26b; 26c) is in the form of a lifting unit (32a; 32b; 32c), which is provided to move the fastening elements (22a, 28a; 22b, 28b; 22c, 28c) relative to one another in the axial direction (16a; 16b; 16c) as a result of the first relative movement.
4. Portable-power-tool clamping device according to Claim 3,
   characterized in that the lifting unit (32a; 32b) has at least one lifting element (34a, 90a; 34b, 90b), which is formed at least partially in one piece with one of the fastening elements (22a, 28a; 22b, 28b).
5. Portable-power-tool clamping device according to Claim 4,
   characterized in that the lifting element (34a, 90a; 34b, 90b) is configured in the form of a ramp.
6. Portable-power-tool clamping device at least according to Claim 3,
   characterized in that the lifting unit (32a; 32b; 32c) has at least one lifting element (36a, 92a; 36b, 92b, 158b, 160b; 36c), which is mounted in a movable manner relative to the at least two fastening elements (22a, 28a; 22b, 28b; 22c, 28c) that are movable relative to one another.
7. Portable-power-tool clamping device according to Claim 6,
   characterized in that the lifting element (36b, 92b, 158b, 160b; 36c) is arranged at least partially between the fastening elements (22b, 28b; 22c, 28c).
8. Portable-power-tool clamping device at least according to Claim 6 or 7,
   characterized in that the lifting element (36c) is guided at least partially in annular tracks (38c, 40c) of the at least two fastening elements (22c, 28c) that are movable relative to one another.
9. Portable-power-tool clamping device according to Claim 8,
   characterized in that the lifting element (36c) is formed by at least one rolling body (42c).
10. Portable-power-tool clamping device according to at least one of Claims 1 to 7,
    characterized in that the run-off securing unit (26a) and the uncoupling unit (20a) have at least one common lifting element (36a, 92a).
11. Portable power tool, in particular angle grinder, having a portable-power-tool clamping device according to one of the preceding claims.

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