Work apparatus

Abstract

A work apparatus (1 figure 1) has a tool (9 figure 1) which can be driven in a rotating manner around a rotational axis 11 and a protective hood 10 which extends over at least a part of the periphery

Description

05 03 24 Work apparatus The invention relates to a work apparatus having a tool, which can be driven in a 5 rotating manner around a rotational axis, and having a protective hood, which extends over at least a part of the periphery of the tool, wherein the protective hood is attached to a housing part of the work apparatus. DE 103 48 395 Al discloses an electric machine tool which has a protective hood. The 10 electric machine tool has a stop which delimits the rotational movement of the protective hood with respect to a housing of the electric machine tool. Until it reaches the stop, the protective hood can rotate with respect to the housing over a comparatively large angular range with respect to the housing. 15 An object of the invention is to propose a work apparatus of the generic type which is constructed in a simple manner and which even in the case of high forces acting on the protective hood renders it possible for the protective hood to be adequately secured against rotation. 20 This object is achieved by a work apparatus having the features of claim 1. It is provided that the work apparatus has at least two rotation-locks for the protective hood which are arranged in different angular positions around the rotational axis. Each rotation-lock is formed by virtue of the fact that one of the components of the protective 25 hood and the housing part has a protruding section which cooperates with a section of the other component of the protective hood and the housing part. The rotation-locks secure the protective hood on the housing part in a positive-locking manner against rotation around the rotational axis. Each rotation-lock prevents the protective hood moving with respect to the housing part around the rotational axis. In so doing, the 30 protective hood is prevented from rotating with respect to the housing part within the usual component tolerances. Only small relative movements which arise due to component tolerances of the protective hood and the housing part can be possible. The 05 03 24 relative movements, i.e. the rotational movement of one component with respect to the other around the rotational axis, which are possible due to component tolerances of the protective hood and the housing part, are advantageously less than 5°, in particular less than 3° around the rotational axis. The protective hood is secured to the housing part 5 against rotation within the manufacturing tolerances. The protective hood is not rotatably mounted on the housing part. The protective hood is attached to the housing part in a position which is constructively predetermined within the manufacturing tolerances. There is no provision for the operator to rotate the protective hood to enable different positions of an engagement area of the tool. Each rotation-lock advantageously 10 prevents the protective hood rotating with respect to the housing part in both rotational directions around the rotational axis. The work apparatus is a work apparatus in the case of which the operator is not intended to rotate the protective hood with respect to the housing part. Until now, it has been 15 common practice to screw the protective hood to the housing part of such work apparatuses. In this case, the rotation-lock acts by virtue of the at least one screw connection. Screw connections are non-positive locking connections. According to the invention, at least two rotation-locks are now provided in different 20 angular positions around the rotational axis, which positively secure the protective hood on the housing part against rotation around the rotational axis. Securing the protective hood in a positive-locking manner by means of at least two anti-rotation locks renders possible a simple design in which the protective hood is prevented from rotating with respect the housing part even in the case of very high forces acting on the protective 25 hood. This results in a simple and stable construction. In addition, one or more nonpositive locking connections can be provided between the protective hood and the housing part, The angular position of a rotation-lock around the rotational axis refers to the angle 30 which the line connecting the rotational axis and a central axis of the rotation-lock includes with a reference line that runs through the rotational axis. The angular position is measured in this case in an intersection plane that extends perpendicular to the 05 03 24 rotational axis. Different angular positions of two rotation-locks around the rotational axis arise if the angle which the line connecting the rotational axis and the central axis of the respective rotation-lock includes with a reference line for the rotation-locks has a different value for the two rotation-locks. The angular position is determined in this 5 case for all rotation-locks in relation to the same reference line. The rotation-lock is itself advantageously formed by the protective hood and the housing part and not by additional, separate elements which are connected to a base body of the protective hood or a base body of the housing part. As a consequence, a 10 simple construction is achieved. At the same time, the rotation-locks can be designed in a simple manner to be sufficiently stable. It is particularly preferred that the protruding section of one component and / or the section of the other component are designed as one piece with a base body of the protective hood and / or housing part. In an advantageous manner, the protruding section of one component and / or the section of the other 15 component are molded onto a metal casting and produced in the same material as the casting. In an advantageous manner, the protective hood is attached to the housing part of the work apparatus by way of at least one fastening element. The protruding section of one 20 component engages advantageously in a receptacle of the other component. The fastening element protrudes advantageously into the protruding section. The protruding section is advantageously a section which forms a receptacle for the fastening element. The protruding section has advantageously a dual function, namely both the function of receiving the fastening element and also the function of forming the rotation-lock by 25 engaging into the receptacle of the other component. In a particularly advantageous design, one of the components of the protective hood and the housing part has at least one screw boss which forms the protruding section, and the fastening element is a fastening screw that is screwed into the screw boss. The screw 30 boss can be designed both to cooperate with its outer periphery in the case of a positivelocking rotation-lock and also with a thread that is formed in the interior of the screw 05 03 24 boss in the case of a non-positive locking connection of the protective hood and the housing part. This results in a simple and stable construction. A maximum distance of 2 mm is advantageously formed between the protruding section 5 of one component of the protective hood and the housing part and the section of the other component of the protective hood and the housing part. In this case, the distance is in a plane perpendicular to the rotational axis and measured in the peripheral direction to the rotational axis. By way of example in the radial direction in relation to the rotational axis, a greater distance is formed between the sections, since only the distance 10 in the peripheral direction is relative for the rotation-lock. The distance is advantageously designed so that possible relative movements of the protective hood and the housing part are less than 5°, in particular less than 3° around the rotational axis. Advantageously, a first edge is formed on the protective hood and a second edge is 15 formed on the housing part. The first edge and the second edge engage advantageously in each other and thereby secure the protective hood in a positive-locking manner against rotation around the rotational axis on the housing part. It is advantageously provided that one edge engages over the other edge. Advantageously, the first edge and the second edge form a rotation-lock which is provided in addition to at least one 20 rotation-lock that is formed by a fastening element. Advantageously, at least one edge is a non-circular. It is particularly preferred that at least one edge has an oval shape. In an advantageous embodiment, both edges are noncircular, in particular oval. In an alternative embodiment, it is possible to provide that 25 the at least one edge, in particular both edges, are eccentric to the rotational axis. Advantageously, at least one edge runs around the rotational axis. As a consequence, the at least one edge forms a protection against contamination in the area of the rotational axis. The edge advantageously has no interruptions. It is preferred that both edges run 30 around the rotational axis. Advantageously, at least one edge, in particular both edges, runs / run around all fastening elements. As a consequence, the fastening elements are protected by the at least one edge, in particular by both edges, against contamination. 05 03 24 Advantageously, a maximum distance of 2 mm is formed between the first edge and the second edge. In this case, the distance is measured perpendicular to the rotation-lock. The edges advantageously form a rotation-lock. The rotational locks formed by the 5 protruding sections and the rotation lock formed by the edges enable at the most a very small rotation of the protective hood and the housing part. The minimal rotation which the rotation locks allow are advantageously of the same order of magnitude for all rotation locks. 10 Advantageously, the first edge engages over the second edge. Advantageously, at least one protruding section is formed by an elevation on an edge and said elevation engages in a depression of the other edge and forms therewith at least one rotation-lock. Advantageously, a plurality of elevations is formed on at least one of 15 the edges and said elevations engage in depressions of the other edge. Advantageously each elevation together with each depression forms a rotation-lock on its side walls. Particularly advantageously, a plurality of elevations are provided on the first edge and said elevations in each case engage in a depression of the second edge and / or a plurality of elevations are provided on the second edge and said elevations in each case engage in 20 a depression on the first edge. In the case of one embodiment in which the first edge engages over the second edge on its outer side, it is advantageously provided that elevations on the first edge protrude in the direction towards the rotational axis and elevations on the second edge protrude away from the rotational axis. Particularly advantageously, the elevations and depressions of the two edges form a meshing 25 arrangement. Advantageously, at least one elevation and / or at least one depression of the first edge and / or of the second edge has a side wall which is at a distance of less than 2 mm from an associated side wall of the other edge. In this case, the distance can also be 0 mm so 30 that the side walls abut against each other. 05 03 24 Advantageously the elevations and depressions form rotational-locks which secure the protective hood with respect to the housing part against rotation in both rotational directions. The rotation-locks prevent the protective hood moving with respect to the housing part around the rotational axis. By preventing the movement of the protective 5 hood with respect to the housing part around the rotational axis it means in the present case that the protective hood can be rotated over an angle of less than 5°, in particular less than 3° and it is prevented from rotating over a larger angle in both rotational directions by each rotation-lock. 10 In an advantageous embodiment variant, the at least one protruding section is arranged on the protective hood. It is preferred that a plurality of protruding sections is provided. The plurality of protruding sections is advantageously connected to one another by way of ribs. The protruding sections advantageously protrude beyond the free ends of the ribs. The extent to which the protruding sections advantageously protrude towards the 15 free ends of the ribs is measured parallel to the rotational axis. The protrusion can advantageously be at least 1.5 mm. Advantageously, the protrusion is 1.5 mm to 5 mm. In an alternative design, the protruding sections can also be flush with the ribs and not protrude beyond the ribs. 20 Advantageously, a head of the at least one fastening element rests on an overlay that protrudes above a base of the housing part. This makes it easy to achieve a sufficient length of the fastening element and a defined contact surface of the head of the fastening element. A sufficient length of the fastening element is particularly important if the fastening element is a screw. If the fastening element is a screw, a particularly 25 advantageous design is that the screw is screwed into a thread formed in the protective hood. In a preferred design, the thread can be formed in a screw boss that forms a protruding section. However, a design in which the protruding section is formed separately from the screw boss can also be advantageous. 30 Advantageously, the protective hood is attached to the housing part by way of at least one first fastening element and at least one second fastening element. The first fastening element and the second fastening element are advantageously at different distances from 05 03 24 the rotational axis. This allows a fastening element to be arranged at a greater distance from the rotational axis in an area where sufficient installation space is available. Due to the greater distance from the rotational axis, greater torques can be transmitted around the rotational axis by way of this fastening element or the fastening element can be 5 designed smaller. This enables an advantageous, compact and stable construction of the work apparatus. Advantageously, the work apparatus is a cut-off machine having a drive motor and the housing part of the work apparatus, to which the protective hood is attached, is an 10 outrigger of the cut-off machine. The outrigger advantageously has a longitudinal central axis. The outrigger advantageously has a free end. The free end is the end of the outrigger lying remote from a housing of the work apparatus. A central axis of the first fastening element 15 advantageously is at a first distance from the free end measured in the direction of the longitudinal central axis. The central axis of the second fastening element advantageously is at a second distance from the free end measured in the direction of the longitudinal central axis. The second distance is advantageously smaller than the first distance. A central axis of the second fastening element is advantageously arranged 20 closer to the rotational axis than a central axis of the first fastening element. By virtue of the fact that the fastening element that is arranged closer to the free end of the outrigger is at a smaller distance from the rotational axis, it is possible for the tool to be submerged a comparatively greater depth into the workpiece. By virtue of the fact that the central axis of the first fastening element is arranged further away from the 25 rotational axis, greater torques around the rotational axis can be absorbed by way of the second fastening element so that a greater stability of the arrangement is achieved. Advantageously, at least three rotation-locks are provided. The angular distance between two rotation-locks that are adjacent in the peripheral direction around the 30 rotational axis is advantageously not the same for all rotation-locks that are adjacent in the peripheral direction around the rotational axis. If the angular distances between the adjacent rotation-locks are determined for all rotation-locks that are adjacent in the 05 03 24 peripheral direction, different values arise for at least two angular distances. Advantageously, the angular distance between adjacent rotation-locks, which are arranged close to the free end of the outrigger, is greater than from adjacent rotationlocks, wherein at least one rotation-lock is arranged further away from the free end of 5 the outrigger. Also as a consequence, it is possible to achieve a comparatively great submersion depth of the tool into a workpiece at the free end of the outrigger. Further advantageous embodiments are created by any combination of individual elements of the exemplary embodiments. 10 An exemplary embodiment of the invention is explained below with reference to the drawing. In the drawings: Fig. 1 shows a side view of a work apparatus, 15 Fig. 2 shows a perspective view of a base body of an outrigger of a work apparatus with a protective hood arranged thereon, Fig. 3 shows a sectional exploded view of the arrangement shown in Fig. 2, 20 Fig. 4 shows an enlarged section of Fig. 3 in the area of the protective hood, Fig. 5 shows a perspective view of the area of the free end of the outrigger shown in Fig. 2 from the side facing the protection hood, 25 Fig. 6 shows a sectional side view of the arrangement shown in Fig. 2, Fig. 7 shows a section along the line VII-VII shown in Fig. 6, 30 Fig. 8 shows a side view of the arrangement shown in Fig. 2, Fig. 9 shows a section along the line IX-IX shown in Fig. 8, 05 03 24 Fig. 10 shows a perspective view of a base body of an outrigger of a further exemplary embodiment of a work apparatus with a protective hood arranged thereon, 5 Fig. 11 shows an exploded view of a section of the arrangement shown in Fig. 10, Fig. 12 shows a perspective view of a section of the protective hood from the side facing the outrigger, 10 Fig. 13 shows a perspective view of the area of the free end of the outrigger shown in Fig. 10 from the side facing the protection hood, Fig. 14 shows a side view of the arrangement shown in Fig. 10, 15 Fig. 15 shows a section along the line XV-XV shown in Fig. 14, Fig. 1 shows a cut-off machine as an exemplary embodiment for a work apparatus 1. The work apparatus lisa hand-guided, hand-held work apparatus 1. The work 20 apparatus 1 is held and guided by the operator during the operation. The work apparatus 1 has a housing 2 on which are arranged a handle 3 and a bale handle 5 for guiding the work apparatus 1 during the operation. Other handles are also provided. A drive motor 6 is arranged in the housing 2. An operator controlled element 4 for activating the drive motor 6 is provided on the rear handle 3. In the exemplary embodiment, the drive motor 25 6 is an electric motor which is supplied with energy by a battery 7 that is contained in the housing 2. The drive motor 6 can also be designed as a combustion motor. The work apparatus 1 comprises an outrigger 8 in the exemplary embodiment. The outrigger 8 has a fastening end 32 and a free end 31. The ends 32 and 31 delimit the 30 outrigger 8 in its longitudinal direction. The outrigger 8 is attached to the housing 2 in the area of its fastening end 32. The free end 31 is arranged remotely from the housing 2. A tool 9, in the exemplary embodiment a cut-off disk, is rotatably mounted on the 27 02 25 outrigger 8 in the area of the free end 31. The tool 9 is mounted on the outrigger 8 in such a manner as to be able to rotate around a rotational axis 11. During the operation, the tool 9 is driven by the drive motor 6 in a rotating manner in a rotational direction 26 around the rotational axis 11. Fig. 1 also illustrates a rotational direction 34 which runs 5 in the counter direction to the rotational direction 26. A protective hood 10 is attached to the outrigger 8. The protective hood 10 covers the tool 9 over part of its periphery. 10 In the exemplary embodiment the outrigger 8 is constructed from a base body 12 illustrated in Fig. 2 and a cover 23 illustrated in Fig. 1 and attached to the base body 12. A transmission device for transmitting the drive movement from the drive motor 6 to the tool 9 is advantageously arranged in the outrigger. The cover 23 is advantageously removable so that the transmission device is accessible for maintenance purposes. The 15 transmission device can, for example, be a belt drive arranged in the outrigger 8. A different construction of the outrigger 8 can also be advantageous. As Fig. 2 shows, the base body 12 has a drivetrain opening 16 which is adjacent to the fastening end 32 of the outrigger 8 and through which a means for transmitting the drive 20 movement, for example a drive shaft of the drive motor 6, can protrude. Adjacent to the free end 31 of the outrigger 8, the base body 12 has an output opening 17 through which an output shaft can protrude and the tool 9 is attached to said output shaft. In the area of the output opening 17, the protective hood 10 is attached to the base body 12 of the outrigger 8. In the exemplary embodiment, fastening elements are provided for this 25 purpose, namely a first fastening element 13, a second fastening element 14 and a third fastening element 15. In the embodiment example, the fastening elements 13 to 15 are designed as fastening screws. The fastening elements 13 to 15 protrude through the base body 12 of the outrigger 8 and are screwed into the protective hood 10. The fastening elements 13, 14, 15 can also be advantageously designed differently, for example as 30 bolts, pins or the like. 27 02 25 The base body 12 comprises a flat base 30, which has the drivetrain opening 16 and the output opening 17. As Fig. 2 shows, the base body 12 has a hub 18 which encompasses the output opening 5 17. The hub 18 is designed as an edge that extends around the output opening 17 and protruding into the interior of the outrigger 12. The hub 18 protrudes from the base 30. In the exemplary embodiment, the base body 12 has a plurality of stiffening ribs 19. Some of the reinforcement ribs 19 extend from the hub 18. In the exemplary 10 embodiment, the outrigger 8 has three elevations 21 and a head 20 of a fastening element 13 to 15 rests on each of said elevations. In the exemplary embodiment, reinforcing ribs 19 also extend from the elevations 21. The reinforcing ribs 19 and the elevations 21 protrude from the base 30. 15 Fig. 3 shows an exploded view of the base body 12 of the outrigger 8 and the protective hood 10. As Fig. 3 shows, the elevations 21 each have a through opening 40 for the fastening elements 13 to 15. The protective hood 10 has three protruding sections 24 on the side facing the outrigger 8. The area in which the protruding sections 24 are arranged is encompassed by a first edge 22 that protrudes in the direction of the base 20 body 12 of the outrigger 8. The first edge 22 runs around the area in which the protruding sections 24 are arranged. The first edge 22 advantageously has no interruptions. As Fig. 3 shows, the first fastening element 13 has a central axis 43. The second 25 fastening element 14 has a central axis 44. The third fastening element 15 has a central axis 45. The central axes 43, 44 and 45 are also illustrated in Fig. 6. As Fig. 4 shows, the protruding sections 24 are each designed as a screw boss. The protruding sections 24 each have a thread opening 35. The fastening elements 13 to 15 30 (Fig. 3) are screwed into the thread openings 35. The protruding sections 24 are connected to one another by way of ribs 28. In the exemplary embodiment, some of the ribs 28 run around the output opening 17. An opening 50 is arranged in the protective 05 03 24 hood. Ribs 28 that run around the output opening 50 connect the protruding sections 24. In addition, ribs 28 are provided which connect the protruding sections 24 to the edge of the opening 50 or the edge 22. 5 As Fig. 4 shows, the protruding sections 24 protrude beyond the end sides of the ribs 28. The protruding sections 24 protrude beyond the ribs 28 by a protrusion b. The protrusion b is advantageously 1.5 mm to 5 mm. As Fig. 4 also shows, reinforcing ribs 39 are provided on the outer periphery of the first 10 edge 22 and they protrude from the edge 22 to a side wall 41 of the protective hood 10. The side wall 41 defines an area of the protective hood 10 which partially covers a flat side of the tool 9. Fig. 5 shows a section of the base body 12 of the outrigger 8 from the side facing the 15 protective hood 10. As Fig. 5 shows, the hub 18, which encompasses the output opening 17, also extends to this side of the base body 12. As Fig. 5 also shows, each through opening 40 is encompassed by a receptacle 25. The receptacle 25 is designed in each case as a depression on the base body 12. The receptacles 25 are encompassed by a peripheral edge 42. The edge 42 transitions on the side remote from the output opening 20 17 into a second edge 27 which peripherally encompasses the area of the through openings 40 and the receptacles 25. The second edge 27 corresponds in its shape to the first edge 22 and is dimensioned such that the first edge 22 of the protective hood 10 can engage over the second edge 27 of the outrigger 8, as will be further explained below. An alternative design in which the second edge 27 engages over the first edge 22 25 can also be advantageous. Fig. 6 shows the base body 12 in a side view when viewed in the direction parallel to the rotational axis 11. As Fig. 6 shows, the base body 12 of the outrigger 8 has a longitudinal central axis 33 which extends from the fastening end 32 to the free end 31. 30 In the exemplary embodiment, the rotational axis 11 intersects the longitudinal central axis 33. 27 02 25 The central axis 43 of the first fastening element 13 is at a distance d from the free end 31. The distance d is measured along the longitudinal central axis 33 to the point at which the longitudinal central axis 33 intersects the free end 31. The central axis 43 of the first fastening element 13 is at a distance e from the rotational axis 11. The distance 5 e is advantageously at least 30%, in particular at least 40% of the distance d. In the exemplary embodiment, the distance e is approx. 50% of the distance d. The central axes 44 and 45 of the first fastening elements 14 and 15 are at a distance c from the free end 31. In the exemplary embodiment, the central axes 44 and 45 are at 10 the same distance from the free end 31. However, different distances of the central axes 44 and 45 from the free end 31 can also be advantageous. The distance c is smaller than the distance d. The fastening elements 14 and 15 are arranged closer to the free end 31 in the direction of the longitudinal central axis 33 than the first fastening element 13. 15 The rotational axis 11 is at a distance m from the free end 31 measured along the longitudinal central axis 33. The distance c is smaller than the distance m of the rotational axis 11 from the free end 31. All the distances c, d, e and m are measured along the longitudinal central axis 33 in the 20 side view illustrated in Fig. 6 when viewed in the direction of the rotational axis 11. As Fig. 7 shows, the first edge 22 engages over the second edge 27 on its outer periphery. In the exemplary embodiment, the protruding section 24 protrudes beyond the first edge 22 by a distance a. In this case, the protrusion a is measured parallel to the 25 rotational axis 11. The base body 12 of the outrigger 8 rests on the protruding sections 24 of the protective hood 10. Fig. 7 also illustrates how the fastening elements 13 to 15 protrude through the through openings 40 of the housing part 12 and are screwed into the thread openings 35 of the protective hood 10. In this case, the heads 20 of the fastening elements 13 to 15 rest in each case on an overlay 29 which protrudes from the 30 base 30 of the base body 12. The overlays 29 protrude out of the base 30 on the side remote from the protective hood 10. The second edge 27 protrudes out of the base 30 on the side facing the protective hood 10. 05 03 24 As Fig. 7 shows, the protruding sections 24 protrude into receptacles 25 of the base body 12. Each protruding section 24 together with the associated receptacle 25 forms a rotation-lock which secures the protective hood 10 on the outrigger 8 against rotation 5 around the rotational axis 11. A first rotation-lock 36 is formed in the area of the first fastening elements 13, a second rotation-lock 37 is formed in the area of the second fastening element 14 and a third rotation-lock 38 is formed in the area of the third fastening element 15. Each rotation-lock 36, 37, 38 secures the protective hood 10 in a positive-locking manner against rotation around the rotational axis 11 so that the 10 protective hood 10 is prevented from moving with respect to the base body 12 of the outrigger 8 around the rotational axis 11. The elevations 21 extend starting from the base 30 and the overlays 29 are formed on said elevations. Furthermore, the reinforcing ribs 19 protrude from the base 30. The 15 protruding sections 24 and the second edge 27 protrude from the base 30 on the side of the base 30 facing the protective hood 10. Fig. 9 shows a section along the line IX-IX in Fig. 8 in the area of the connection of the protective hood 10 to the base body 12 of the outrigger 8. Fig. 9 shows a section 20 perpendicular to the rotational axis 11. The protruding sections 24 are at a maximum distance h from the edge 42 of the receptacles 25 in the peripheral direction around the rotational axis 11. The distance h can be formed by way of example due to manufacturing tolerances. The distance h is advantageously a maximum 2 mm. In this case, the distance h is measured in a plane perpendicular to the rotational axis 11 and 25 tangential to the peripheral direction around the rotational axis 11, in other words perpendicular to an axis which intersects the rotational axis 11 in a perpendicular manner. It is also possible to provide that at least one protruding section 24 rests at least in the peripheral direction around the rotational axis 11 on the edge 42 of the associated receptacle 25 so that the distance h is 0 mm. 30 As Fig. 9 shows, both the second edge 27 on the base body 12 and also the first edge 22 on the protective hood 10 are formed continuously around the rotational axis 11. In this 05 03 24 case, the edges 22 and 27 are not circular but rather asymmetrical. On the side close to the free end 31, the edges 22 and 27 advantageously run approximately in a circular manner around the rotational axis 11. On the side remote from the free end 31, the distance of the edges 22 and 27 from the rotational axis 11 increases uniformly, so that 5 the edges 22 and 27 are approximately egg-shaped in the sectional view. The central axis 44 of the fastening element 14 is at a distance f from the rotational axis 11. The central axis 45 of the fastening element 15 is at a distance g from the rotational axis 11. In the exemplary embodiment, the distances f and g are the same and the central axes 44 and 45 are arranged symmetrically with respect to the longitudinal central axis 33 of the 10 outrigger 8 in the illustrated sectional plane perpendicular to the rotational axis 11. The central axis 43 of the fastening element 13 is at a distance e from the rotational axis 11. The distance e is greater than the distances f and g. The rotation-locks 36 and 37 have an angular distance a around the rotational axis 10, 15 which is measured perpendicular to the rotational axis 11 in the sectional plane shown in Fig. 9. The angular distance a is measured in the peripheral direction around the rotational axis 11. The angular distance a is measured in a sectional plane perpendicular to the rotational axis 11 between a straight line which intersects the rotational axis 11 and the central axis 43 of the fastening element 13 and a straight line which intersects 20 the rotational axis 11 and the center axis 44 of the fastening element 14. The rotationlocks 37 and 38 have an angular distance P in the peripheral direction around the rotational axis 11. The angular distance P is greater than the angular distance a. The angular distance P is measured in a sectional plane perpendicular to the rotational axis 11 between a straight line which intersects the rotational axis 11 and the central axis 44 25 of the fastening element 14 and a straight line which intersects the rotational axis 11 and the center axis 45 of the fastening element 15. The rotation-locks 38 and 36 have an angular distance y around the rotational axis 11. The angular distance y is measured in a sectional plane perpendicular to the rotational axis 11 between a straight line which intersects the rotational axis 11 and the central axis 45 of the fastening element 15 and a 30 straight line which intersects the rotational axis 11 and the center axis 43 of the fastening element 13. In the exemplary embodiment, the angular distances a and y are the same. The angular distance P is greater than the angular distances a and y. The 05 03 24 rotation-locks 36, 37 and 38 are therefore distributed unevenly over the periphery around the rotational axis 11. The rotation-locks 36, 37 and 38 are arranged in different angular positions around the 5 rotational axis 11. If the longitudinal central axis 33 in the section which extends in Fig. 9 from the rotational axis 11 to the left hand side is taken as a reference, then the first rotation-lock 36 is arranged in an angular position of 0°, the second rotation-lock 37 is arranged in an angular position which corresponds to the angular distance a and the third rotation-lock 38 is arranged in an angular position which corresponds to the sum 10 of the angular distances a and p. As Fig. 9 also shows, the edges 22 and 27 in the exemplary embodiment are at a small distance k from one another. The distance k is advantageously a maximum 2 mm. In an alternative embodiment, it is possible to provide by way of example that the distance k 15 is 0 mm and the edges 22 and 27 abut against each other, advantageously at least in a partial region of their length. The distance k is advantageously approx, in the order of magnitude of the distance h. Due to their asymmetrical design around the rotational axis 11, the edges 22 and 27 likewise form a rotation-lock for the protective hood 10 with respect to the base body 12 of the outrigger 8. By virtue of the fact that the distances h 20 and k are approx, the same, the edges 27 and 22 and rotation-locks 36, 37 and 38 come into contact with each other after approximately the same slight relative rotation of the protective cover and base body 12 so that all the rotation-locks jointly prevent a rotation of the protective hood 10 relative to the base body 12. The rotation-locks 36 to 38 and the edges 22 and 27 secure the protective hood 10 against a rotation of the protective 25 hood 10 with respect to the outrigger 8 in the rotational direction 26 and in the opposite rotational direction 34 illustrated in Fig. 1. As a consequence, the rotation-locks 36 to 38 prevent the protective hood 10 from rotating both in the rotational direction 26 of the tool 9 and also in the counter rotational direction 34. 30 The rotation-locks 36 to 38 secure the protective hood 10 in a positive-locking manner against rotation around the rotational axis 11 in both rotational directions 26 and 34 with respect to the base body 12. 05 03 24 In the exemplary embodiment, the protective hood 10 has the protruding section 24 and the receptacle 25 is formed in the outrigger 8. In an alternative embodiment, it is possible to provide that the receptacle 25 is formed on the protective hood 10 and the 5 protruding section 24 is formed on the outrigger 8. The protruding section 24 and the receptacle 25 are advantageously designed as one piece and integrally with the protective hood 10 and the outrigger 8 so that no additional components are required for the rotation-locks 36, 37 and 38. The edges 22 and 27 are advantageously formed integrally with the base body 12 of the outrigger 8 and integrally with the protective 10 hood 10. The figures 10 to 15 show a further exemplary embodiment of the outrigger and the protective hood of a work apparatus. Identical reference characters identify mutually corresponding elements in all the exemplary embodiments. Advantageously, elements 15 that are not described in detail in the exemplary embodiment according to Figs. 10 to 15 are designed as in the preceding exemplary embodiment, so that reference is made to the description of this exemplary embodiment. As figures 10 and 11 show, the first edge 22 has elevations 46 that protrude in the 20 direction towards the rotational axis 11. The second edge 27 has elevations 47 which protrude away from the rotational axis 11. The elevations 46 and 47 engage with one another and act as an additional rotation-lock around the rotational axis 11. In the exemplary embodiment, the elevations 46 and the elevations 47 are designed as teeth. However, a different design of the elevations 46 and / or 47 is also advantageously 25 possible. Fig. 12 shows the design of the first edge 22 of the protective hood 10 in detail. Depressions 48 are formed between elevations 46 that are adjacent in the peripheral direction. In the exemplary embodiment, elevations 46 and depressions 48 are arranged 30 in an alternating manner over a large part of the peripheral length of the first edge 22. In the exemplary embodiment, no elevations 46 are provided in the areas of the first edge 22 that are arranged radially outside the protruding sections 24. In the exemplary 05 03 24 embodiment, these areas are adjacent to the edges 40 that run around the receptacles 25 on the outrigger 8 which are illustrated in Fig. 13. The length n measured along the first edge 22 of an elevation 46 is advantageously 0.5 5 times to 2 times a length p measured along the first edge 22 of an adjacent depression 48. As Fig. 12 shows, each elevation 46 has a first side wall 51 and a second side wall 52 which delimit the elevation 46 and the adjacent depressions 48. 10 Fig. 13 shows the design of the second edge 27 of the base body 12 of the outrigger 8 in detail. Depressions 49 are formed between elevations 47 that are adjacent in the peripheral direction. In the exemplary embodiment, elevations 47 and depressions 49 are arranged in an alternating manner over a large part of the peripheral length of the 15 second edge 27. In the exemplary embodiment, no elevations 47 are arranged in the area of the receptacles 25. The length o measured along the second edge 27 of an elevation 47 is advantageously 0.5 times to 2 times a length r measured along the second edge 27 of an adjacent 20 depression 49. As Fig. 13 shows, each elevation 47 has a first side wall 53 and a second side wall 54 which delimit the elevation 47 and the adjacent depressions 49. 25 Fig. 14 shows the position of the section through the edges 22 and 27 illustrated in Fig. 15. As Fig. 15 shows, the first edge 22 engages over the second edge 27 on its outer periphery. In this case, the elevations 46 on the first edge 22 engage in the depressions 49 on the second edge 27. The elevations 47 on the second edge 27 engage in the depressions 48 on the first edge 22. The elevations 46, 47 and depressions 48, 49 form a 30 meshing arrangement between the edges 22 and 27. As a consequence, the torques that can be supported around the rotational axis 11 by way of the edges 22 and 27 can be easily increased compared to the design in the previous exemplary embodiment. 05 03 24 The side walls 51 and 54 of the elevations 46 and 47 are adjacent to each other. The side walls 51 and 54 of the elevations 46 and 47 are advantageously adjacent to each other or are at a distance t of less than 2 mm from each other. Within the manufacturing 5 tolerances, the side walls 51 and 54 prevent the protective hood 10 from rotating in the rotational direction 34. The side walls 52 and 53 of the elevations 46 and 47 are adjacent to each other. The side walls 52 and 53 of the elevations 46 and 47 are advantageously adjacent to each other or 10 are at a distance s of less than 2 mm from each other. Within the manufacturing tolerances, the side walls 52 and 53 prevent the protective hood 10 from rotating with respect to the base body 12 in the rotational direction 26. Each elevation 46 together with the associated depression 49 forms a rotation-lock 57. 15 Within the manufacturing tolerances, each rotation-lock 57 that is formed by an elevation 46 and an associated depression 49 prevents the protective hood 10 from moving around the rotational axis 11. Each elevation 47 together with the associated depression 48 forms a rotation-lock 58. 20 Within the manufacturing tolerances, each rotation-lock 58 that is formed by an elevation 47 and an associated depression 48 prevents the protective hood 10 from moving around the rotational axis 11. Each rotation-lock 57 and each rotation-lock 58 secures the protective hood 10 in a 25 positive-locking manner against rotation around the rotational axis 11 so that the protective hood 10 is prevented from moving with respect to the base body 12 of the outrigger 8 around the rotational axis 11. By preventing the movement of the protective hood 10 with respect to the base body 12 around the rotational axis 11, it means in the present case that the protective hood 10 can be rotated over an angle of less than 5°, in 30 particular less than 3° and it is prevented from rotating over a larger angle in both rotational directions 26 and 34 by each rotation-lock 57 and 58. 05 03 24 As Fig. 15 shows, the side walls 52 and 53 in the illustrated section are inclined perpendicular to the rotational axis 11 with respect to a radial 56 to the rotational axis 11 by an angle a which is less than 90°. Advantageously, the angle a for at least one side wall 52 or 53, preferably for all side walls 52 and 53, is less than 45°, in particular less 5 than 30°. The side walls 51 and 54 in the illustrated section are inclined perpendicular to the rotational axis 11 with respect to a radial 55 to the rotational axis 11 by an angle 5 which is less than 90°. Advantageously, the angle 5 for at least one side wall 51 or 54, 10 preferably for all side walls 51 and 54, is less than 45°, in particular less than 30°. As Fig. 15 also shows, the radial 55 that indicates the position of the rotation-lock 57 that is formed by the side walls 51 and 54 includes an angle p with the region of the longitudinal center line 33 that extends to the left hand side of the rotational axis 11 in 15 the illustration in Fig. 15. The radial 56, which indicates the position of the rotation-lock 58 that is formed by the side walls 52 and 53, includes with the region of the longitudinal center line 33 that extends to the left hand side of the rotational axis 11 in the illustration in Fig. 15 an angle k which is greater than the angle p. The rotation-locks 57 and 58 are arranged accordingly in different angular positions around the rotational 20 axis 11. Advantageously, all rotation-locks 57 and 58, which are formed by cooperating side walls 51 and 54 or by co-operating side walls 52 and 53, are arranged in different angular positions around the rotational axis 11. It may be provided that the angle a or the angle 5 for one or more side walls 51, 52, 53 25 and / or 54 is 0°. In the exemplary embodiment, the side walls 51, 52 of an elevation 46 and the side walls 53, 54 of an elevation 47 are each inclined in the opposite direction with respect to the radials 55 and 56, respectively, with the result that a widened base area of the elevations 46 and 47 and a good dissipation of forces which are introduced by the elevations 46 of the protective hood 10 into the elevations 47 of the base body 12 30 is produced. A further advantageous embodiment for a work apparatus 1 is produced if the work apparatus 1 has only rotation-locks 57 and 58 and does not have rotation-locks 36, 37 and 38. 03 24

Claims

1. A work apparatus having a tool (9), which can be driven in a rotating manner around a rotational axis (11), and having a protective hood (10), which extends 5           over at least a part of the periphery of the tool (9), wherein the protective hood(10) is attached to a housing part of the work apparatus (1), wherein the working apparatus (1) has at least two rotation-locks (36, 37, 38, 57, 58) for the protective hood (10) which are arranged in different angular positions around the rotational axis (11), wherein each rotation-lock (36, 37, 38, 57, 58) is10          formed by virtue of the fact that one of the components of the protective hood(10) and the housing part has a protruding section (24) which cooperates with a section of the other component of the protective hood (10) and the housing part and secures the protective hood (10) on the housing part in a positive-locking manner against rotation around the rotational axis (11), so that the protective15          hood (10) is prevented from moving with respect to the housing part around therotational axis (11).

2. The work apparatus as claimed in claim 1, whereinthe protective hood (10) is attached to the housing part of the work20           apparatus (1) by way of at least one fastening element (13, 14, 15).

3. The work apparatus as claimed in claim 2, wherein so as to provide the positive-locking security against rotation around the rotational axis (11) the protruding section (24) of one component of the25          protective hood (10) and the housing part engages in a receptacle (25) of theother component of the protective hood (10) and the housing part and that the fastening element (13, 14, 15) protrudes into the protruding section.

4. The work apparatus as claimed in claim 2,30          wherein one of the components of the protection hood (10) and the housing parthave at least one screw boss which forms the protruding section (24), and that a05 03 24fastening element (13, 14, 15) is a fastening screw that is screwed into the screw boss.

5. The work apparatus as claimed in claim 1,5          wherein a first edge (22) is formed on the protective hood (10) and that a secondedge (27) is formed on the housing part, wherein the first edge (22) and the second edge (27) engage with each other and thereby secure the protective hood (10) on the housing part in a positive-locking manner against rotation around the rotational axis (11).

106. The work apparatus as claimed in claim 5, wherein at least one edge (22, 27) is non-circular.

7. The work apparatus as claimed in claim 5,15           wherein at least one edge (22, 27) runs around the rotational axis (11).

8. The work apparatus as claimed in claim 5, wherein a maximum distance (k) of 2 mm is formed between the first edge (22) and the second edge (27), wherein the distance (k) is measured perpendicular to 20           the rotational axis (11).

9. The work apparatus as claimed in claim 5, wherein the first edge (22) engages over the second edge (27).25   10. The work apparatus as claimed in claim 5,wherein at least one protruding section is formed by an elevation (46, 47) on an edge (22, 27) and engages in a depression (48,49) of the other edge (27, 22) and forms therewith at least one rotation-lock (57, 58).30   11. The work apparatus as claimed in claim 1,wherein the at least one protruding section (24) is arranged on the protective hood (10).05 03 2412. The work apparatus as claimed in claim 1, wherein a plurality of protruding sections (24) are provided, which are connected to one another by way of ribs (28).

513. The work apparatus as claimed in claim 1, wherein the protective hood (10) is attached to the housing part by way of at least one first fastening element (13) and at least one second fastening element (14, 15), wherein the first fastening element (13) and the second fastening10           element (14, 15) are at different distances (e; f, g) from the rotational axis (11).

14. The work apparatus as claimed in claim 1, wherein the work apparatus (1) is a cut-off machine having a drive motor (6) and that the housing part of the work apparatus (1), to which the protective hood (10)15           is attached, is an outrigger (8) of the cut-off machine.

15. The work apparatus as claimed in claim 1, wherein at least three rotation-locks (36, 37, 38) are provided and that the angular distance (a, p, y) between two rotation locks (36, 37, 38) that are20           adjacent in the peripheral direction around the rotational axis (11) is not thesame for all adjacent rotation-locks (36, 37, 38).

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