GB2461793A

GB2461793A - Protective guard rotation-locking device

Info

Publication number: GB2461793A
Application number: GB0911880A
Authority: GB
Inventors: Florian Esenwein
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2008-07-11
Filing date: 2009-07-08
Publication date: 2010-01-20
Anticipated expiration: 2029-07-08
Also published as: GB0911880D0; RU2009126417A; GB2492869B; DE102008040369A1; GB201210189D0; GB2461793B; CN101623850A; GB2492869A; DE102008040369B4

Abstract

A protective hood rotation-locking device 40a for a hand-held power tool in particular for an angle grinding machine (12a,figure 1), is provided for rotation-locking between the hand-held power tool and a protective hood unit (16a, figure 1), in particular in the event of damage to a tool (18a, figure 1), having a clamping band 20a which comprises a rotation-locking region 22a having a positive-locking profile 24a. A force flow element 26a is provided for reducing a density of a force flow, compared with a pure positive-locking profile, in at least part of the rotation-locking region 22a. The positive locking profile 24a may comprise a profile with flanks (44a, figure 5) differing in shape with respect to their circumferential direction (28a, 30a, figure 5) such that they provide differing positive-locking connections in the respective circumferential directions (28a, 30a, figure 5).

Description

Protective hood rotation-locking device

Prior art

The invention starts from a protective hood rotation-locking device according to the precharacterising clause of Claim 1.

A protective hood rotation-locking device for a hand-held power tool, which is provided for rotation-locking between the hand-held power tool and a protective hood unit, in particular in the event of damage to a tool, is already known. The known protective hood rotation-locking device comprises a clamping band, which comprises a rotation-locking region having a pure positive-locking profile.

Advantages of the invention The invention starts from a protective hood rotation-locking device for a hand-held power tool, in particular for an angle grinding machine, which is provided for rotation-locking between the hand-held power tool and a protective hood unit, in particular in the event of damage to a tool, having a clamping band, which comprises a rotation-locking region having a positive-locking profile.

It is proposed that the protective hood rotation-locking device comprises a force flow element which is provided for reducing a density of a force flow, compared with a pure positive-locking profile, in at least part of the rotation-locking region. In this context, "provided" is to be understood as meaning in particular specially equipped and/or specially designed. "Rotation-locking" is to be understood here as meaning in particular locking against undesired rotation of a protective hood unit, in particular in the event of damage to a tool, relative to a hand-held power tool during operation. Preferably, the protective hood unit is to rotate here through at most 9Q0 relative to the hand-held power tool. Furthermore, "in the event of damage to a tool" is to be understood as meaning in particular a tool bursting during operation of the hand-held power tool, it then being possible for individual tool parts to be flung outwards owing to a rotation of the tool.

The term "clamping band" is to be understood here as meaning in particular a component and/or element which is provided for fastening the protective hood unit to a receiving unit of the hand-held power tool. Preferably, the clamping band is, for this purpose, fixedly connected to a protective hood neck of the protective hood unit, so that the clamping band is connected in a rotationally locked manner to the protective hood unit. Preferably, the clamping band is connected to the protective hood neck of the protective hood unit by a welded connection, although other types of connection which appear appropriate to a person skilled in the art are also possible, such as, for example, a soldered connection. Advantageously, the clamping band is fabricated from sheet steel, although it may also be fabricated from other materials which appear appropriate to a person skilled in the art. The term "rotation-locking region" is to be defined here as in particular a region of the clamping band which is provided, by special shaping, for rotation-locking, in particular by means of a nonpositive-locking, positive-locking and/or materially-united connection, between the protective hood unit and the hand-held power tool. Advantageously, the rotation-locking region extends along a circumferential direction of the clamping band over a partial region of the clamping band. A "positive-locking profile" is to be understood here as meaning in particular a cross-section of a component and/or an element which is provided for producing a positive-locking connection to a further component and/or element. Advantageously, the positive-locking profile in the configuration according to the invention is arranged in the rotation-locking region of the clamping band. A "pure positive-locking profile" is to be understood here as meaning in particular a positive-locking profile which has, in the circumferential direction, a constant, uniform structure, preferably a wave profile, such as, in particular, a purely wavy clamping band, and has a cross-section in the radial direction having a cross-sectional area which has a constant extension over an entire height of the clamping band in a radial direction of the clamping band.

The term "force flow" defines here in particular a path of a force and/or moment in a component from a point of application -a place where the force is introduced -up to a place at which the force and/or moment are absorbed by a reaction force and/or reaction moment. A "density of a force flow" is to be understood here as meaning in particular an intensity of the force flow with reference to an area and/or volume.

An effective and in particular reliable protection of an operator of the hand-held power tool from the tool rotating during operation of the hand-held power tool and/or in particular in the event of damage to the tool, such as, for example, in the event of the tool bursting, from parts of the tool flying around in the direction of the operator, can be achieved by the configuration of the protective hood rotation-locking device according to the invention. In this case, a dimensioning of the protective hood rotation-locking device is designed in such a way that forces which occur in the event of damage to the tool can be absorbed by the protective hood rotation-locking device, these forces being transmitted to the protective hood unit by tool parts of the burst tool striking the protective hood unit, while retaining a protective function for the operator.

Furthermore, it is proposed that the force flow element is essentially provided for preventing deformation of the rotation-locking region. For this purpose, in the configuration of the protective hood rotation-locking device according to the invention, the force flow element is preferably formed as a reinforcement of a further component and/or element, in particular of the rotation-locking region of the clamping band, and/or the force flow element is formed as a bridge-like component and/or element, the force flow in this case being directed at least partly via the component and/or element. Preferably, the force flow element is produced from sheet steel, although other materials which appear appropriate to a person skilled in the art may also be used. The force flow element is connected, at least partly, fixedly to the clamping band, such as, in particular, by a welded connection at at least two points of the force flow element, although other types of connection which appear appropriate to a person skilled in the art are also possible. The deformation and associated wear or associated possible failure of a claimed component of the hand-held power tool, such as, in particular of the clamping band, can advantageously be reduced or prevented.

A compact protective hood rotation-locking device can be achieved and forces which occur can advantageously be absorbed by the protective hood rotation-locking device when the force flow element is advantageously arranged in the rotation-locking region along a circumferential direction of the clamping band. A "circumferential direction" is to be understood in this context as meaning in particular a direction which runs along a longitudinal direction of a protective hood neck of the protective hood unit around the latter and/or which runs around an axis of rotation of the tool in a mounted state of the protective hood unit.

Furthermore, the force flow element has elevations which are arranged one behind the other at least partly along a circumferential direction of the clamping band and are provided for a positive-locking connection between the clamping band and the force flow element. "Elevations which are arranged one behind the other" are to be understood here as meaning in particular wave-like and/or sawtooth-like elevations in a radial direction of the clamping band and/or of the force flow element which are arranged alternately at least in a partial region of the force flow element along the circumferential direction of the clamping band and/or force flow element. Preferably, the elevations of the force flow element form a mating contour with respect to the positive-locking profile of the rotation-locking region of the clamping band, in order to achieve advantageously a secure connection between the force flow element and the clamping band. As a result of this, forces which occur in the clamping band, in particular in the event of damage to the tool, can be absorbed and/or carried away particularly advantageously by the force flow element and failure of the protective hood rotation-locking device can be prevented.

Advantageously, the force flow element is arranged on a side of the clamping band facing away from a receiving unit. Preferably, the receiving unit comprises a receiving neck, to which the protective hood unit can be fastened, and a base plate, which is provided for fastening the receiving unit to the hand-held power tool. Simple mounting of the clamping band on the receiving unit or on the receiving neck can be achieved by the configuration according to the invention, since the force flow element is arranged outside a mounting region of the clamping band.

Furthermore, the force flow element is formed at least partly integrally with the clamping band. "Integrally" is to be understood here as meaning in particular formed in one piece and/or monobloc and/or as one component. As a result, a constructionally simple protective hood rotation-locking device can be achieved. Moreover, as a result, separate components, structural space, outlay on assembly, and costs can advantageously be saved.

Preferably, the protective hood rotation-locking device comprises a protective hood unit which is arranged in a rotationally locked manner on the clamping band on a side substantially opposite the rotation-locking region along a circumferential direction of the clamping band. In this context, "side substantially opposite" is to be understood as meaning in particular a side along the circumferential direction, with at least one point of a first region, in particular of the rotation-locking region, being arranged on one side of the clamping band and being connectable to at least one point of a second region, in particular of the protective hood unit, by a straight line which extends through a central point and/or a central region of an area enclosed by the clamping band, the central region comprising at most 20% of the area enclosed by the clamping band. As a result, advantageous utilisation of a substantially entire circumference of the clamping band can be achieved.

Furthermore, it is proposed that the rotation-locking region and/or the force flow element are arranged along the circumferential direction of the clamping band between a closing unit of the clamping band and the protective hood unit. The term "between" is to be understood here as meaning in particular an arrangement spatially along the circumferential direction. Furthermore, a "closing unit" is to be understood as meaning in particular a unit which is provided for fastening the protective hood unit to the receiving unit, in particular by clamping the clamping band. As a result, a constructionally simple arrangement of different functional units on the clamping band can be achieved.

In a further configuration of the invention, it is proposed that the positive-locking profile has, along a circumferential direction of the clamping band, at least one positive-locking element which has differing flanks in respect of their shaping in the circumferential direction and in an opposite circumferential direction and are provided for obtaining differing positive-locking connections in the circumferential directions. "A circumferential direction of the clamping band" is to be understood in this context as meaning in particular a clockwise direction along the circumferential direction of the clamping band. Furthermore, an "opposite circumferential direction" is to be understood as meaning an anticlockwise direction along the circumferential direction of the clamping band. The term "differing flanks" defines here in particular that at least two flanks of the positive-locking element differ, along the circumferential direction, in their shape, in particular with regard to a gradient and/or the shape of the flanks, such as, for example, different curvatures of the flanks, along the two circumferential directions. It is, however, also conceivable for the flanks to be designed symmetrically or in another shape which appears appropriate to a person skilled in the art. "Differing positive-locking connections" are to be understood here as meaning in particular positive-locking connections which can transmit and/or absorb forces of different sizes in dependence on a loading direction along the circumferential directions. By means of the configuration of the protective hood rotation-locking device according to the invention, advantageously in one direction a convenient position adjustment of the protective hood unit can be achieved and in an opposite direction reliable rotation-locking can be achieved. As a result, an operator-friendly protective hood rotation-locking device can be created.

Preferably, the at least one positive-locking element is of sawtooth-like form. In this context, "sawtooth-like" is to be understood as meaning a shape and/or a cross-Section through a component and/or an element, which shape or cross-section has flanks with a different gradient and/or different curvature, so that a direction dependence of transmittable forces results. A sawtooth-like positive locking profile which is formed from a plurality of positive-locking elements can additionally have a wave profile superimposed on it. The positive-locking profile can in this case be produced particularly cost-effectively and moreover a constructionally simple protective hood rotation-locking device can be achieved.

Furthermore, it is proposed that the protective hood rotation-locking device comprises a receiving unit which is provided for receiving at least partly the clamping band and/or the protective hood unit. In this case, particularly stable support of the protective hood unit, in particular if high forces and/or moments act on the protective hood unit, such as, for example, in the event of a tool bursting during operation of the hand-held machine tool, can be achieved in a constructionally simple manner.

Advantageously, the receiving unit has, along a substantially entire circumferential direction, positive-locking elements which have differing flanks in respect of their shaping in the circumferential direction and in an opposite circumferential direction to the circumferential direction and are provided for obtaining differing positive_locking connections in the circumferential directions. It is, however, also conceivable for the flanks to be designed symmetricallY or in another shape which appears appropriate to a person skilled in the art. By means of the configuration of the protective hood rotation-locking device according to the invention, advantageously a convenient and versatile position adjustment of the protective hood unit on the receiving unit can be achieved and moreover advantageously a force distribution over a plurality of positive-locking elements can be achieved.

Furthermore, it is proposed that the positive-locking elements are of sawtooth-like form, in order to achieve a direction dependence of transmittable forces or' the receiving unit. As a result, a variable protective hood rotation-locking device can be achieved, since the sawtooth-like positive-locking elements can be adapted to an area of application of the hand-held power tool.

Drawing Further advantages emerge from the following description of the drawing. Exemplary embodiments of the invention are illustrated in the drawing. The drawing, description and claims contain numerous features in combination. A person skilled in the art will also consider the features, expediently, individually and combine them to form appropriate further combinations.

In the drawing: Fig. 1 shows a schematic illustration of an angle grinding machine having a protective hood rotation-locking device according to the invention, Fig. 2 shows a schematic illustration of the protective hood rotation-locking device according to the invention, Fig. 3 shows a schematic illustration of a receiving unit of the protective hood rotation-locking device according to the invention, Fig. 4 shows a schematic illustration of a protective hood unit having a clamping band of the protective hood rotation-locking device according to the invention, Fig. 5 shows a detail view of a positive-locking profile of the clamping band from Figure 4, Fig. 6 shows a cross-section of the clamping band along the line V-V from Figure 5, Fig. 7a shows a u-profile-shaped cross-section of an alternative clamping band along the line V-V from Figure 5, Fig. 7b shows a cross-section with grooves of an alternative clamping band along the line V-V from Figure 5, Fig. 8 shows a protective hood unit having an alternative clamping band having a force flow element, matched to an outer contour of the clamping band, of the protective hood rotation-locking device according to the invention, and Fig. 9 shows a protective hood unit having an alternative clamping band having an integrally formed force flow element of the protective hood rotation-locking device according to the invention.

Description of the exemplary embodiments

Figure 1 illustrates, in a view from above, a hand-held power tool 12a, formed by an angle grinding machine 14a, a protective hood unit 16a and a protective hood rotation-locking device lOa (not illustrated in more detail here) The angle grinding machine 14a comprises a hand-held power tool housing 50a and a main handle 52a integrated in the hand-held power tool 50a and extending in the direction of a longitudinal direction 56a of the angle grinding machine 14a on a side 54a facing away from a tool iSa formed by a cut-off disc. The hand-held power tool housing 50a comprises a motor housing 58a and a gearbox housing 60a. In addition, the angle grinding machine 14a has, for receiving the protective hood unit 16a and/or the tool 18a, a receiving unit 36a (not illustrated in more detail here) which is connected to the gearbox housing 60a by means of four screw connections. The protective hood l6a in a mounted state covers an angular region of the tool 18a of about 180°. An auxiliary handle 62a is arranged on the angle grinding machine l4a on the gearbox housing 60a. The auxiliary handle 62a extends transversely with respect to the longitudinal direction 56a of the angle grinding machine 14a.

Figure 2 illustrates a protective hood rotation-locking device iOa according to the invention for the angle grinding machine 14a. The protective hood rotation-locking device lOa is provided for rotation-locking between the hand-held power tool 12a and a protective hood unit 16a, in particular in the event of damage to the tool 18a. For this purpose, the protective hood rotation-locking device l0a has a clamping band 20a which comprises a rotation-locking * region 22a having a positive-locking profile 2a, in order to absorb and/or transmit forces which occur in the event of damage to the tool 18a.

Furthermore, the protective hood rotation-locking device lOa comprises the protective hood unit 16a, which is arranged in a rotationally locked manner on the clamping band 20a on a side 38a substantially opposite the rotation-locking region 22a, along a circumferential direction 28a, 30a of the clamping band 20a. The clamping band 20a is connected in a rotationally locked manner to a protective hood neck 64a of the protective hood unit 16a by means of spot welding, the protective hood neck 64a being arranged within an area surrounded by the clamping band 20a, along a radial direction 66a of the clamping band 20a. The clamping band 20a may, however, also be connected in a rotationally locked manner to the protective hood neck 64a by adhesive bonding or soldering. The protective hood neck 64a extends in this case substantially along a circumferential direction 26a, 30a of the clamping band 20a and along a direction which runs substantially along an axis of rotation 68a of the tool 18a in a mounted state of the protective hood unit 16a on the angle grinding machine 14a.

The protective hood unit 16a has, in addition to the protective hood neck 64a, a protective hood 70a which extends substantially along the circumferential direction 28a, 30a of the clamping band 20a over an angular region of about 180°.

Furthermore, the protective hood rotation-locking device lOa comprises the receiving unit 36a which is provided for receiving at least partly the clamping band 20a and/or the protective hood unit 16a. The receiving unit 36a has a central opening 72a which is provided for receiving a tool spindle (not shown specifically here) of the angle grinding machine 14a, via which the tool l8a is rotationally driven during operation of the angle grinding machine 14a (see Figure 3 in this regard) Furthermore, the protective hood rotation-locking device lOa has a force flow element 26a which is provided for reducing a density of a force flow, compared with a pure positive-locking profile, in at least part of the rotation-locking region 22a. In this case, the force flow element 26a is arranged in the rotation-locking region 22a along a circumferential direction 28a, 30a of the clamping band 20a. The force flow element 26a is formed as a separate component from sheet steel and is connected to the rotation-locking region 22a of the clamping band 20a by spot welding. It is, however, also possible to connect the force flow element 26a to the clamping band 20a by soldering or adhesive bonding. Furthermore, the force flow element 26a may also be welded, adhesively bonded or soldered to a plurality of positive-locking elements 42a of the positive-looking profile 24a along the circumferential direction 28a, 30a of the clamping band 20a. In order to enable simple mounting of the protective hood unit l6a on the receiving unit 36a by an operator of the angle grinding machine 14a, the force flow element 26a is arranged on a side 34a of the clamping band 20a facing away from the receiving unit 36a, so that the operator merely guides the protective hood unit 16a, in a mounting position, over a receiving neck 74a of the receiving unit 36a and subsequently clamps the protective hood unit l6a in a desired position on the receiving neck 74a by means of a closing unit 40a of the clamping band 20a. The rotation-locking region 22a and the force flow element 26a are arranged between the closing unit 40a of the clamping band 20a and the protective hood unit 16a along the circumferential direction 28a, 30a of the clamping band 20a (see Figure 4 in this regard) The closing unit 40a forms a unit on the clamping band 20a which is preferably provided for fastening the protective hood unit 16a to the hand-held power tool 12a, in particular to the receiving unit 36a, and has at least one closing element 76a, such as, for example, a screw, a closing lever, etc., it being possible to fasten the protective hood unit 16a to the hand-held power tool 12a by means of the closing unit 40a positively and/or non-positively. In this configuration of the protective hood rotation-locking device lOa according to the invention, the closing unit 40a is formed by a screw connection, and the ends of the clamping band 20a are connected and/or clamped to one another in a manner known to a person skilled in the art.

After closing of the closing unit 40a or clamping of the protective hood unit 16a on the receiving neck 74a, the positive-locking profile 24a of the rotation-locking region 22a of the clamping band 20a engages in positive-locking elements 46a of the receiving neck 74a. The positive-locking elements 46a of the receiving neck 74a of the receiving unit 36a are arranged along a substantially entire circumferential direction 28a, 30a of the receiving neck 74a (see Figure 3 in this regard) . The positive-locking elements 46a have differing flanks 48a in respect of their shaping in the circumferential direction 28a and in an opposite circumferential direction 30a to the circumferential direction 28a and are provided for obtaining differing positive-locking connections to the positive-locking profile 24a of the rotation-locking region 22a in the circumferential directions 28a, 30a. The positive-locking profile 24a likewise has, for this purpose, a plurality of positive-locking elements 42a which are arranged substantially over the entire rotation-locking region 22a along the circumferential direction 28a, 30a of the clamping band 20a. The positive-locking elements 42a likewise have differing flanks 44a in respect of their shaping in the circumferential direction 28a and in an opposite circumferential direction 30a to the circumferential direction 28a (see Figures 4 and 5 in this regard).

The circumferential direction 28a of the receiving neck 74a and/or of the clamping band 20a runs clockwise, while the opposite circumferential direction 30a of the receiving neck 74a and/or of the clamping band 20a runs anticlockwise. Here, a viewing direction for defining the clockwise direction is to be defined by a direction perpendicular from a surface to be machined by the angle grinding machine 14a while machining in the direction of the angle grinding machine 14a, with the tool iSa, in particular a grinding disc, being arranged parallel to the surface to be machined.

The flanks 44a of the positive-locking elements 42a are differently designed in order to achieve a direction-dependent force transmission (see Figure 5 in this regard) The flanks 44a of the positive-locking elements 42a which are arranged, in a viewing direction along the circumferential direction 28a of the clamping band 20a, in the rotation-locking region 22a of the clamping band 20a have a greater gradient -with reference to an amount of the gradient -than the flanks 4a which are arranged, in a viewing direction along the opposite circumferential direction 30a of the clamping band 20a, in the rotation-locking region 22a of the clamping band 20a. Thus, in the event of damage to the tool 18a, when fragments are flung against the protective hood unit l6a substantially along the opposite circumferential direction 30a of the clamping band 20a, rotation-locking is achieved by the gradient of the flanks 44a which are arranged, in a viewing direction along the circumferential direction 28a of the clamping band 20a, in the rotation-locking region 22a of the clamping band 20a. The gradient of the flanks 44a in this case counteracts a rotary movement of the protective hood unit 16a, since sliding of the positive-locking elements 42a of the positive-locking profile 24a of the rotation-locking region 22a along the positive-locking elements 46a of the receiving neck 74a is restricted or prevented. The flanks 48a of the positive-locking elements 46a of the receiving neck 74a have, for this purpose, a mating contour with respect to the flanks 44a of the positive-locking elements 42a of the positive-locking profile 24a of the rotation-locking region 22a (see Figure 3 in this regard) The positive-locking elements 46a of the receiving unit 36a and the positive-locking elements 42a of the positive-locking profile 24a of the rotation-locking region 22a are of sawtooth-like form. By means of such a configuration of the flanks 44a, 48a of the positive-locking elements 42a, 46a, a particularly advantageous positive-locking connection between the positive-locking elements 46a of the receiving unit 36a and the positive-locking elements 42a of the positive-locking profile 24a of the rotation-locking region 22a, along a direction of rotation 78a of the tool l8a, is achieved. The direction of rotation 78a of the tool l8a runs substantially along the opposite circumferential direction 30a. In the event of damage to the tool l8a, when the tool iBa bursts, fragments of the tool 18a are flung against the protective hood unit l6a substantially along the direction of rotation 78a of the tool iSa and/or along the opposite direction of rotation 30a of the clamping band 20a. Thus, rotation of the protective hood unit 16a in the event of such damage is prevented by the positive-locking connection between the positive-locking elements 46a of the receiving unit 36a and the positive-locking elements 42a of the positive_locking profile 24a of the rotation-locking region 22a. The rotation-locking of the protective hood unit 16a is additionally promoted by the force flow element 26a, since the force flow element 26a is essentially provided for preventing deformation of the rotation-locking region 22a, in order that large forces can be transmitted or absorbed by the rotation-locking region 22a. A position adjustment of the protective hood unit 16a counter to the direction of rotation 78a of the tool and/or along the circumferential direction 28a of the clamping band 20a is made possible to the operator by the differing flanks 48a of the positive-locking elements 46a of the receiving unit 36a and the differing flanks 44a of the positive-locking elements 42a of the positive-locking profile 24a of the rotation-locking region 22a, in addition to the rotation-locking in the direction of rotation 78a of the tool 18a.

For position adjustment in the circumferential direction 28a, the closing unit 40a of the c1aiiping band 20a must be at least partly released in order to achieve play in the positive-locking connection.

Figure 3 illustrates the receiving unit 36a of the protective hood rotation-locking device lOa according to the invention. The receiving unit 36a has on the receiving neck 74a a slot BOa which runs along the circumferential direction 28a, 30a of the receiving unit 36a and is provided for axially locking the protective hood unit l6a.

For this purpose, the protective hood unit l6a has a lug 82a on an inside of the protective hood neck 64a facing the receiving unit 16a (see Figures 4, 8 and 9 in this regard) The lug 82a of the protective hood unit l6a is guided into the slot 80a, when mounting the protective hood unit 16a on the receiving unit 36a, by means of a recess 84a (not illustrated in more detail here) which extends on a circumference 86a of the receiving neck 74a along the axis of rotation 68a. The lug 82a is provided, in cooperation with the recess 84a on the circumference 86a of the receiving neck 74a, as a coding means for preventing mounting of the protective hood unit 16a on hand-held power tools 12a unsuitable therefor. Furthermore, the lug 82a may be prestressed by means of a spring element (not shown specifically here), so that the protective hood unit 16a is slightly prestressed after mounting on the receiving unit 36a.

Figure 5 illustrates a partial region of the positive-locking profile 24a. The positive-locking profile 24a has, along the circumferential direction 28a, 30a, a constant wave structure having the differing flanks 44a. In this case, a cross-section 88a of the positive-locking profile 24a has a constant extension along the radial direction 66a of the clamping band 20a over an entire height of the clamping band 20a in the radial direction 66a of the clamping band 20a. The height of the clamping band 20a here extends perpendicularly to the radial direction 66a of the clamping band 20a and perpendicularly to the circumferential direction 28a, 30a of the clamping band 20a (see Figure 6 in this regard) Figure 6 illustrates a cross-section 88a of the positive-locking profile 24a from Figure 5. The cross-section 88a of the positive-locking profile 24a extends along the circumferential direction 28a, 30a of the clamping band 20a over the substantially entire rotation-locking region 22a of the clamping band 20a. Rotation-locking of the protective hood rotation-locking device iQa is effected analogously to Figure 2.

Figures 7a to 9 illustrate alternative exemplary embodiments. Components, features and functions which remain essentially the same are denoted fundamentally by the same reference symbols. To distinguish the exemplary embodiments, however, the letters a to e are added to the reference symbols of the exemplary embodiments. The following description is restricted essentially to the differences from the exemplary embodiment in Figures 1 to 6, while reference may be made to the description of the exemplary embodiment in Figures 1 to 6 with regard to components, features and functions which remain the same.

Figure 7a is an alternative cross-section 88b of a positive-locking profile 24b from Figure 6. The cross-section 88b is formed substantially as a U-profile, edge regions 90b, 92b of the cross-section 88b being designed as the force flow element 26b. The force flow element 26b is thus formed integrally with the positive-locking profile 24b. The edge regions 9Db, 92b have, for this purpose, a greater material thickness in a radial direction 66b than a region 94b delimited by the edge regions 9Db, 92b.

Rotation-locking of a protective hood rotation-locking device lOb is effected analogously to Figure 2.

Figure 7b illustrates a further alternative cross-section 88c of a positive-locking profile 24c from Figure 6. The cross-section 88c of the positive-locking profile 24c has grooves 96c and/or rib-like reinforcements 98c which do not extend over an entire height of a clamping band 20c and which run along a circumferential direction 28c, 30c of the clamping band 20c. The grooves 96c and/or rib-shaped reinforcements 98c extend in a radial direction 66c of the clamping band 20c. In this case, the grooves 96c and/or the rib-like reinforcements 98c form a force flow element 26c.

Rotation-locking of a protective hood rotation-locking device lOc is effected analogously to Figure 2.

Figure 8 illustrates a protective hood unit 16d having an alternative clamping band 20d and/or force flow element 26d, to Figure 4, of a protective hood rotation-locking device lOd according to the invention. The force flow element 26d in this case has elevations 32d which are arranged one behind the other at least partly along a circumferential direction 28d, 30d of the clamping band 20d and are provided for a positive-locking connection between the clamping band 20d and the force flow element 26d in the circumferential direction 28d, 30d. Rotation-locking of the protective hood rotation-locking device lOd is effected analogously to Figure 2.

Figure 9 illustrates a protective hood unit 16e having an alternative clamping band 20e and/or force flow element 26e, to Figure 4, of a protective hood rotation-locking device lOe according to the invention. The force flow element 26e in this case is formed integrally with the clamping band 20e. Rotation-locking of the protective hood rotation-locking device lOe is effected analogously to Figure 2.