Abstract:
The disclosure relates to a portable power tool comprising at least one coupling device which can be coupled to a power tool separation device comprising at least one cutting unit and at least one guide unit for guiding the cutting unit. The portable power tool comprises at least one storage device which is provided to stow the machine tool separation device at least when it is coupled to the coupling device.

Description:
This application is a 35 U.S.C. §371 National Stage Application of PCT/EP2012/000919, filed on Mar. 2, 2012, which claims the benefit of priority of Ser. No. DE 10 2011 005 041.8, filed on Mar. 3, 2011 in Germany, the disclosures of which are incorporated herein by reference in their entirety. 
     BACKGROUND 
     There are already known portable power tools that have a coupling device, which can be coupled to a power-tool parting device that has a cutting strand and a guide unit for guiding the cutting strand. 
     SUMMARY 
     The disclosure is based on a portable power tool having at least one coupling device, which can be coupled to a power-tool parting device that has at least one cutting strand and at least one guide unit for guiding the cutting strand. 
     It is proposed that the portable power tool comprise at least one stowage device, which is provided to stow the power-tool parting device, at least when coupled to the coupling device. A “portable power tool” is to be understood here to mean, in particular, a power tool, in particular a hand-held power tool, that can be transported by an operator without the use of a transport machine. The portable power tool has, in particular, a mass of less than 40 kg, preferably less than 10 kg, and particularly preferably less than 5 kg. A “coupling device” is to be understood here to mean, in particular, a device provided to operatively connect the power-tool parting device to the portable power tool, by means of a positive and/or non-positive connection, for the purpose of working a workpiece. In particular, when the coupling device has been coupled to the power-tool parting device and the portable power tool is in an operating state, forces and/or torques can be transmitted from the drive unit of the portable power tool to the power-tool parting device, for the purpose of driving the cutting strand. The coupling device is therefore preferably realized as a tool receiver. The expression “provided to” is intended here to define, in particular, specially configured and/or specially equipped. The term “drive unit” is intended here to define, in particular, a unit provided to generate forces and/or torques for driving the cutting strand. Preferably, for the purpose of generating forces and/or torques by means of the drive unit, thermal energy, chemical energy and/or electrical energy is converted into energy of motion. In particular, the drive unit is realized such that it can be directly and/or indirectly coupled to the cutting strand. Particularly preferably, the drive unit comprises at least one rotor that has an armature shaft, and at least one stator. Preferably, the drive unit is realized as an electric motor. It is also conceivable, however, for the drive unit to be of another design, considered appropriate by persons skilled in the art. 
     A “cutting strand” is to be understood here to mean, in particular, a unit provided to locally undo an atomic coherence of a workpiece to be worked, in particular by means of a mechanical parting-off and/or by means of a mechanical removal of material particles of the workpiece. Preferably, the cutting strand is provided to separate the workpiece into at least two parts that are physically separate from each other, and/or to part off and/or remove, at least partially, material particles of the workpiece, starting from a surface of the workpiece. Particularly preferably, the cutting strand, in at least one operating state, is moved in a revolving manner, in particular along a circumference of the guide unit. A “guide unit” is to be understood here to mean, in particular, a unit provided to exert a constraining force upon the cutting strand, at least along a direction perpendicular to a cutting direction of the cutting strand, in order to define a possibility for movement of the cutting strand along the cutting direction. Preferably, the guide unit has at least one guide element, in particular a guide groove, by which the cutting strand is guided. Preferably, the cutting strand, as viewed in a cutting plane, is guided by the guide unit along an entire circumference of the guide unit, by means of the guide element, in particular the guide groove. Preferably, the guide unit is realized as a guide bar. The term “guide bar” is intended here to define, in particular, a geometric form that, as viewed in the cutting plane, has a fully closed outer contour, comprising at least two straight lines that are parallel to each other and at least two connecting portions, in particular arcs, that each interconnect mutually facing ends of the straight lines. The guide unit therefore has a geometric shape that, as viewed in the cutting plane, is composed of a rectangle and at least two circle sectors disposed on opposing sides of the rectangle. 
     The term “cutting plane” is intended here to define, in particular, a plane in which the cutting strand, in at least one operating state, is moved, relative to the guide unit, along a circumference of the guide unit, in at least two mutually opposite cutting directions. Preferably, during working of a workpiece, the cutting plane is aligned at least substantially transversely in relation to a workpiece surface that is to be worked. “At least substantially transversely” is to be understood here to mean, in particular, an alignment of a plane and/or of a direction, relative to a further plane and/or a further direction, that preferably deviates from a parallel alignment of the plane and/or of the direction, relative to the further plane and/or the further direction. It is also conceivable, however, for the cutting plane, during working of a workpiece, to be aligned at least substantially parallelwise in relation to a workpiece surface that is to be worked, in particular if the cutting strand is realized as an abrasive. “At least substantially parallelwise” is to be understood here to mean, in particular, an alignment of a direction relative to a reference direction, in particular in one plane, the direction deviating from the reference direction by, in particular, less than 8°, advantageously less than 5°, and particularly advantageously less than 2°. A “cutting direction” is to be understood here to mean, in particular, a direction along which the cutting strand is moved, in at least one operating state, as a result of a driving force and/or a driving torque, in particular in the guide unit, for the purpose of generating a cutting clearance and/or parting-off and/or removing material particles of a workpiece that is to be worked. Preferably, the cutting strand, when in an operating state, is moved, relative to the guide unit, along the cutting direction. 
     The cutting strand and the guide unit preferably together constitute a closed system. The term “closed system” is intended here to define, in particular, a system comprising at least two components that, by means of combined action, when the system has been demounted from a system such as, for example, a power tool, that is of a higher order than the system, maintain a functionality and/or are inseparably connected to each other when in the demounted state. Preferably, the at least two components of the closed system are connected to each other so as to be at least substantially inseparable by an operator. “At least substantially inseparable” is to be understood here to mean, in particular, a connection of at least two components that can be separated from each other only with the aid of parting tools such as, for example, a saw, in particular a mechanical saw, etc. and/or chemical parting means such as, for example, solvents. A “stowage device” is to be understood here to mean, in particular, a device provided to stow the power-tool parting device, when coupled to the coupling device, the power-tool parting device being covered by components of the stowage device and/or of the power-tool housing of the portable power tool. The term “covered” is intended here to define, in particular, a disposition of the power-tool parting device, when the power-tool parting device is in a stowed state, relative to components of the stowage device and/or of the power-tool housing, a total extent of the power-tool parting device, along at least a direction running in the cutting plane, being less than an extent of components of the stowage device and/or of the power-tool housing along the same direction. In particular, the power-tool parting device, when in a stowed state, relative to a total surface are of the power-tool parting device, as viewed in the cutting plane, is more than 20%, preferably more than 30%, and particularly preferably more than 50% covered by components of the stowage device and or of the power-tool housing. Preferably, when the power-tool parting device is in a stowed state, operator contact with cutting elements of the cutting strand can be prevented insofar as possible. When the power-tool parting device is in a stowed state, the cutting elements of the cutting strand are preferably disposed so as to be at least substantially non-contactable by an operator, at least in a partial region of the power-tool parting device. Particularly preferably, operation, in particular a revolving motion of the cutting strand in the guide unit, is prevented when the power-tool parting device is in a stowed state. Preferably, when the power-tool parting device is in a stowed state, it is not possible to perform work on a workpiece by means of the power-tool parting device. Advantageously, the design according to the disclosure makes it possible to achieve a high degree of protection for an operator against injury, when the power-tool parting device is in a stowed state in the stowage device. Moreover, advantageously, a compact portable power tool can be achieved. 
     It is furthermore proposed that the portable power tool comprise a power-tool housing, having at least one side wall that faces toward the stowage device and that, together with a tool covering element of the stowage device, delimits a receiving opening of the stowage device in which the power-tool parting device can be stowed. Preferably, the power-tool parting device, when swiveled into the receiving opening, is disposed, at least in a partial region, as viewed along a direction running at least substantially perpendicularly in relation to the cutting plane of the cutting strand, between the power-tool housing and the tool covering element. Particularly preferably, the power-tool parting device, when swiveled into the receiving opening, as viewed along the direction running at least substantially perpendicularly in relation to the cutting plane, is covered on one side by the power-tool housing and on a further side by the tool covering element. Preferably, the power-tool parting device, when swiveled into the receiving opening, is covered on at least three sides by the power-tool housing and/or the tool covering element. Advantageously, safe stowage of the power-tool parting device can be achieved. 
     Advantageously, the tool covering element is at least partially integral with the power-tool housing. “Integral with” is to be understood to mean, in particular, connected at least in a materially bonded manner, for example by a welding process, an adhesive process, an injection process and/or another process considered appropriate by persons skilled in the art, and/or, advantageously, formed in one piece such as, for example, by being produced from a casting and/or by being produced in a single or multi-component injection process and, advantageously, from a single blank. Advantageously, it is possible to achieve assembly work in assembling of the portable power tool. 
     It is additionally proposed that the coupling device be mounted so as to be movable relative to the power-tool housing, at least when coupled to the power-tool parting device. The expression “mounted so as to be movable” is intended here to define, in particular, a mounting of the coupling device on the portable power tool, at least when coupled to the power-tool parting device, the coupling device, in particular decoupled from an elastic deformation of the coupling device, having a capability to move along at least a travel distance greater than 1 mm, preferably greater than 10 mm, and particularly preferably greater than 50 mm, and/or a capability to move about at least one axis by an angle greater than 10°, preferably greater than 45°, and particularly preferably greater than 60°. Particularly preferably, the coupling device has a capability to move along at least one travel distance and/or about one axis that is independent of a pure closing movement of the coupling device for the purpose of operatively connecting the power-tool parting device to the portable power tool, and/or of an opening movement of the coupling device for the purpose of releasing the operative connection of the power-tool parting device to the portable power tool. Advantageously, by means of the design according to the disclosure, the coupling device can be moved, for example translationally and/or rotationally, into a position suitable for performing work on a workpiece. Advantageously, therefore, a high degree of flexibility can be achieved in working of a workpiece. 
     Preferably, the coupling device is mounted such that it can be swiveled, at least relative to the power-tool housing. Preferably, the power-tool parting device, when coupled to the coupling device, can be swiveled, about a swivel axis running at least substantially perpendicularly in relation to the cutting plane of the cutting strand, into the receiving opening of the stowage device, by means of the coupling device. It is also conceivable, however, for the coupling device, alternatively or additionally, to be mounted such that it can be swiveled, relative to the power-tool housing, abut another swivel axis, considered appropriate by persons skilled in the art. Advantageously, in the case of the portable power tool, it is possible to achieve a pocket-knife principle for stowage of the power-tool parting device. When the power-tool parting device is in a in-in state therefore, the cutting elements of the cutting strand of the power-tool parting device can advantageously be covered, at least partially, by components of the stowage device and/or of the power-tool housing. 
     It is additionally proposed that the portable power tool at least one drive unit and at least one open-loop and/or closed-loop control unit, which is provided to control the drive unit, by open-loop and/or closed-loop control, in dependence on a angular position of the coupling device, relative to the power-tool housing of the portable power tool. An “open-loop and/or closed-loop control unit” is to be understood to mean, in particular, a unit having at least one control device. A “control device” is to be understood to mean, in particular, a unit having at least one processor unit and having at least one memory unit, and having an operating program stored in the memory unit. Particularly preferably, a transmission of a driving torque from the drive unit to the cutting strand is interrupted as soon as the coupling device is swiveled about the swivel axis. Preferably, a supply of energy to the drive unit is prevented, by means of the open-loop and/or closed-loop control unit, when the power-tool parting device is in a in-in state, in order to prevent a driving torque of the drive unit and/or of the transmission unit from being transmitted to the cutting strand. It is also conceivable, however, for the transmission of a driving torque from the drive unit to the cutting strand to be interrupted by means of a mechanical unit. Advantageously, it is possible to achieve a high degree of operating comfort for an operator. 
     Advantageously, the portable power tool has at least one locking unit, which is provided to fix the coupling device, at least when coupled to the power-tool parting device, in an angular position relative to the power-tool housing. The coupling device can thus advantageously be fixed, by an operator, in a required position relative to the power-tool housing. In addition, advantageously, work can be performed on a workpiece in various angular positions of the coupling device relative to the power-tool housing. 
     The disclosure is additionally based on a power-tool parting device for a portable power tool according to the disclosure, having at least one guide unit and at least one cutting strand, which together constitute a closed system. Advantageously, it is possible to achieve a versatile tool for performing work on workpieces. 
     The disclosure is furthermore based on a power-tool system having at least one portable power tool according to the disclosure and having at least one power-tool parting device according to the disclosure. Particularly preferably, the power-tool parting device, when coupled to the coupling device, can be swiveled, about a swivel axis running at least substantially perpendicularly in relation to a cutting plane of the cutting strand, into the receiving opening of the stowage device, by means of the coupling device. Through simple design means, a stowage device for secure stowage of the power-tool parting device can be achieved. 
     The power-tool parting device according to the disclosure and/or the power tool according to the disclosure are not intended in this case to be limited to the application and embodiment described above. In particular, the power-tool parting device according to the disclosure and/or the power tool according to the disclosure may have individual elements, components and units that differ in number from the number stated herein, in order to fulfill a principle of function described herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further advantages are given by the following description of the drawing. The drawing shows an exemplary embodiment of the disclosure. The drawing, the description and the claims contain numerous features in combination. Persons skilled in the art will also expediently consider the features individually and combine them to create appropriate further combinations. 
       In the drawing: 
         FIG. 1  shows a portable power tool according to the disclosure, having a power-tool parting device according to the disclosure, in a schematic representation,  FIG. 2  shows the power tool according to the disclosure, during an operation of swiveling the power-tool parting device according to the disclosure into a receiving opening of a stowage device of the power tool according to the disclosure, in a schematic representation,  FIG. 3  shows the power-tool parting device according to the disclosure, coupled to a coupling device, in a relative angular position in relation to a power-tool housing of the power tool according to the disclosure, in a schematic representation,  FIG. 4  shows a detail view of a transmission unit of the power tool according to the disclosure, in a schematic representation,  FIG. 5  shows a detail view of the power-tool parting device according to the disclosure, in a schematic representation,  FIG. 6  shows a section view, along the line VI-VI from  FIG. 5 , of the power-tool parting device according to the disclosure, in a schematic representation, 
         FIG. 7  shows a detail view of cutter carrying elements a cutting strand of the power-tool parting device according to the disclosure, in a schematic representation,  FIG. 8  shows a further detail view of one of the cutter carrying elements of the cutting strand of the power-tool parting device according to the disclosure, in a schematic representation, and  FIG. 9  shows a detail view of a disposition of the cutter carrying elements in a guide unit of the power-tool parting device according to the disclosure, in a schematic representation. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a portable power tool  10  having a power-tool parting device  14 , which together constitute a power-tool system. The portable power tool  10  has a coupling device  12  for positive and/or non-positive coupling to the power-tool parting device  14 . The coupling device  12  in this case can be realized as a bayonet closure and/or as another coupling device considered appropriate by persons skilled in the art. The coupling device  12  is additionally provided to operatively connect the power-tool parting device  14  to the portable power tool  10 . The coupling device  12  is therefore provided, when in at least one operating state, to be coupled to the power-tool parting device  14 , which comprises at least one cutting strand  16 , and a guide unit  18  for guiding the cutting strand  16 . The portable power tool  10  has a power-tool housing  22 , which encloses a drive unit  30  and a transmission unit  34  of the portable power tool  10 . The drive unit  30  and the transmission unit  38  are operatively connected to each other for the purpose of generating a driving torque that can be transmitted to the power-tool parting device  14 , in a manner already known to persons skilled in the art. In this case, the drive unit  30  and/or the transmission unit  38  are provided, when in a mounted state, to be coupled to a cutting strand  16  by means of the coupling device  12 . The transmission unit  38  of the portable power tool  10  is realized as a bevel gear transmission. The drive unit  30  is realized as an electric motor unit. It is also conceivable, however, for the drive unit  30  and/or the transmission unit  38  to be of a different design, considered appropriate by persons skilled in the art. The drive unit  30  is provided to drive the cutting strand  16  of the power-tool parting device  14 , at least in one operating state, at a cutting speed of less than 6 m/s. The portable power tool  10  in this case has at least one operating mode in which it is possible for the cutting strand  16  to be driven in the guide unit  18  of the power-tool parting device  14 , along a cutting direction  40  of the cutting strand  16 , at a cutting speed of less than 6 m/s. 
     Furthermore, the portable power tool  10  has a stowage device  20 , which is provided to stow the power-tool parting device  14  when coupled to the coupling device  12 . The power-tool parting device  14  in this case is connected to the coupling device  12  in a positive and/or non-positive manner. The power-tool housing  22  of the portable power tool  10 , for the purpose of stowing the power-tool parting device  14 , when coupled to the coupling device  12 , has a side wall  24 , which faces toward the stowage device  20  ( FIGS. 3 and 4 ) and which, together with a tool covering element  26  of the stowage device  20 , delimit a receiving opening  28  of the stowage device  20  in which the power-tool parting device  14  can be stowed. The receiving opening  28  is provided to accommodate the power-tool parting device  14  when the power-tool parting device  14  is in a in-in state. The power-tool parting device  14 , when in a in-in state, is disposed with a partial region in the receiving opening  28  ( FIG. 2 ). 
     The power-tool parting device  14  in this case, when disposed in the receiving opening  28 , in a partial region, as viewed along a direction running at least substantially perpendicularly in relation to a cutting plane of the cutting strand  16 , is disposed between the side wall  24  of the power-tool housing  22  and the tool covering element  26 . The tool covering element  26 , as viewed in a plane perpendicular to the cutting plane of the power-tool parting device  14  coupled to the coupling device  12 , is formed on to the power-tool housing  22  in an L shape ( FIGS. 3 and 4 ). It is also conceivable, however, for the tool covering element  26  to be formed on to the power-tool housing  22  in another configuration, considered appropriate by persons skilled in the art. It is additionally conceivable for the tool covering element  26  to be realized by means of a component that is separate from the power-tool housing  22 , and that is connected to the power-tool housing  22  by means of a positive and/or non-positive connection. An outer wall  42  of the tool covering element  26 , which is disposed on a side of the tool covering element  26  that faces away from the power-tool housing  22 , at an end  44  of the power-tool housing  22  that faces away from the coupling device  12 , runs in the direction of the power-tool housing  22 , starting from the side of the tool covering element  26  that faces away from the power-tool housing  22 , and is connected to the power-tool housing  22  in a materially bonded manner. It is also conceivable, however, for the tool covering element  26  of the side of the tool covering element  26  that faces away from the power-tool housing  22  merely to run parallelwise in relation to the side wall  24  of the power-tool housing  22  that faces towards the tool covering element  26 . 
     For the purpose of stowing the power-tool parting device  14 , the coupling device  12 , when coupled to the power-tool parting device  14 , is mounted so as to be movable relative to the power-tool housing  22  ( FIG. 2 ). The coupling device  12  has a possibility for movement along a travel distance and/or about an axis that is independent of a pure closing movement of the coupling device  12  for the purpose of operatively connecting the power-tool parting device  14  to the portable power tool  10 , and/or of an opening movement of the coupling device  12  for the purpose of releasing the operative connection of the power-tool parting device  14  to the portable power tool  10 . The coupling device  12  in this case can be moved manually, as the result of application of force, by an operator, upon the coupling device  12 , into a position required by the operator and/or for the purpose of stowing the power-tool parting device  14  in the receiving opening  28  of the stowage device  20 . It is also conceivable, however, for the portable power tool  10  to comprise a coupling-device drive unit (not represented in greater detail here), which is provided to drive the coupling device  12  to execute a movement that is independent of the opening movement and/or the closing movement. The coupling-device drive unit can be realized, for example, as an electric motor unit, or as another coupling-device drive unit considered appropriate by persons skilled in the art. 
     The coupling device  12  is mounted such that it can be swiveled relative to the power-tool housing  22 . In this case, the coupling device  12  is mounted such that it can be swiveled about a swivel axis  36  running substantially perpendicularly in relation to a drive-unit longitudinal axis  46  of the drive unit  30 . The coupling device  12  can be moved by an operator into a required angular position of the coupling device  12  relative to the power-tool housing  22 . The angular position of the  12  relative to the power-tool housing  22  in this case lies in an angular range of 180°, by which the coupling device  12  can be swiveled about the swivel axis  36 . The portable power tool  10  comprises a locking unit  34 , which is provided to fix the coupling device  12 , when coupled to the power-tool parting device  14 , and when decoupled from the power-tool parting device  14 , in an angular position relative to the power-tool housing  22 . The locking unit  34  is provided to fix the coupling device  12  in the required angular position, relative to the power-tool housing  22 , by means of positive-fit elements (not represented in greater detail here) and/or non-positive-fit elements (not represented in greater detail here) of the locking unit  34 . For the purpose of actuating the positive-fit elements and/or non-positive-fit elements, the locking device  34  has an operating element  48 . The operating element  48  is realized as an operating lever. It is also conceivable, however, for the operating element  48  to be of a different design, considered appropriate by persons skilled in the art. 
     In addition, when the power-tool parting device  14  is coupled to the coupling device  12 , the swivel axis  36  runs substantially perpendicularly in relation to the cutting plane of the cutting strand  16 . The power-tool parting device  14 , therefore, when coupled to the coupling device  12 , can be swiveled by means of the coupling device  12 , about the swivel axis  36  that runs substantially perpendicularly in relation to the cutting plane of the cutting strand  16 , into the receiving opening  28  of the stowage device  20  ( FIG. 2 ). An operator actuates the operating element  48  of the locking unit  34  in order to undo a fixing of the coupling device  12  in an angular position relative to the power-tool housing  22 . The operator can then swivel the coupling device  12  about the swivel axis  36 , in order to swivel the power-tool parting device  14  into the receiving opening  28  of the stowage device  20 , for the purpose of stowage. For the purpose of maintaining a position of the power-tool parting device  14  in the receiving opening  28 , the operator actuates the operating element  48  of the locking unit again, in order the coupling device  12  in the angular position relative to the power-tool housing  22 , which angular position corresponds to a position of the power-tool parting device  14  when swiveled into the receiving opening  28 . 
     The portable power tool  10  additionally has an open-loop and/or closed-loop control unit  32 , which is provided to control the drive unit  30  by open-loop and/or closed-loop control in dependence on an angular position of the coupling device  12  relative to the power-tool housing  22  of the portable power tool  10 . 
     In this case, transmission of a driving torque from the drive unit  30  and/or the transmission unit  38  to the cutting strand  16  is interrupted, by means of the open-loop and/or closed-loop control unit  32 , as soon as the coupling device  12  is swiveled about the swivel axis  36 . The interruption of transmission of a driving torque in this case may be effected mechanically, electrically and/or electronically, the open-loop and/or closed-loop control unit  32  emitting a pulse to effect interruption. When the power-tool parting device  14  has been swiveled into the receiving opening  28 , the drive unit  30  is mechanically, electrically and/or electronically disconnected from an energy supply by means of the open-loop and/or closed-loop control unit  32 . The open-loop and/or closed-loop control unit  32  is additionally provided to alter a of the drive unit  30  in dependence on an angular position of the coupling device  12 , in the angular range of 180°, relative to the power-tool housing  22 . The open-loop and/or closed-loop control unit  32  in this case is provided to intervene in a motor control system, for controlling the drive unit  30 , in order to alter the drive direction. 
     For the purpose of driving the cutting strand  16 , or for the purpose of transmitting forces and/or torques from the drive unit  30  and/or the transmission unit  38  to the cutting strand  16 , the drive unit  30  has an armature shaft (not represented in greater detail here), which is connected in a rotationally fixed manner to a pinion gear  50  ( FIG. 4 ) of the drive unit  30  and/or of the transmission unit  38 . When in an operating state, the pinion gear  50  meshes with a toothed wheel  52  of the transmission unit  52 . The toothed wheel  52  in this case is realized as a ring gear. It is also conceivable, however, for the toothed wheel  52  to be of another design, considered appropriate by persons skilled in the art. The toothed wheel  52  is connected to an output shaft  54  of the transmission unit  38  in a rotationally fixed manner. On a side that, when in a mounted state, faces toward the cutting strand  16 , the output shaft  54  has a toothed end  56 , which is provided to be directly and/or indirectly coupled to the cutting strand  16 , for the purpose of driving the cutting strand  16 . The toothed end  56  is realized as a hexagon. 
       FIG. 5  shows the power-tool parting device  14  when decoupled from the coupling device  12  of the portable power tool  10 . The power-tool parting device  14  comprises the cutting strand  16  and the guide unit  18 , which together constitute a closed system. The guide unit  18  is realized as a guide bar. The guide unit  18 , as viewed in the cutting plane of the cutting strand  16 , additionally has two convex ends  58 ,  60 . The convex ends  58 ,  60  of the guide unit  18  are disposed at sides of the guide unit  18  that face away from each other. The cutting strand  16  is guided by means of the guide unit  18 . For this purpose, the guide unit  18  has at least one guide element  62  ( FIG. 9 ), by means of which the cutting strand  16  is guided. The guide element  62  in this case is realized as a guide groove  64 , which extends, in the cutting plane of the cutting strand  16 , along an entire circumference of the guide unit  18 . The cutting strand  16  in this case is guided by means of edge regions of the guide unit  18  that delimit the guide groove  64 . It is also conceivable, however, for the guide element  62  to be realized in another manner, considered appropriate by persons skilled in the art, such as, for example, as a rib-type element, formed on to the guide unit  18 , that engages in a recess on the cutting strand  16 . The cutting strand  16 , as viewed in a plane running perpendicularly in relation to the cutting plane, is surrounded on three sides by the edge regions that delimit the guide groove  64  ( FIG. 9 ). During operation, the cutting strand  16  is moved in a revolving manner along the circumference of the guide unit  18 , in the guide groove  64 , relative to the guide unit  18 . 
     The power-tool parting device  14  additionally has a torque transmission element  66 , for driving the cutting strand  16 , that is at least partially mounted by means of the guide unit  18 . The torque transmission element in this case has a coupling recess  68  that, in a mounted state, is coupled to the toothed end  56  of the output shaft  54  ( FIG. 4 ). It is also conceivable, however, for the torque transmission element  66 , when in a coupled state, to be directly coupled to the pinion gear  50  of the drive unit  30  and/or to the toothed wheel  52  of the transmission unit  38 , for the purpose of driving the cutting strand  16 . The coupling recess  68  is disposed concentrically in the torque transmission element  66 . The coupling recess  68  is realized as an internal hexagon. It is also conceivable, however, for the coupling recess  68  to be of another design, considered appropriate by persons skilled in the art. 
     When the torque transmission element  66  is not coupled to the toothed end  56  of the output shaft  54 , the torque transmission element  66  is disposed so as to be movable, transversely in relation to the cutting direction  40  of the cutting strand  16  and/or along the cutting direction  40 , in the guide unit  18  ( FIG. 6 ). The torque transmission element  66  in this case is disposed, at least partially, between two outer walls  70 ,  72  of the guide unit  18 . The outer walls  70 ,  72  run at least substantially parallelwise in relation to the cutting plane of the cutting strand  16 . In outer faces  74 ,  76  of the outer walls  70 ,  72 , the guide unit  18  has a respective recess  78 ,  80 , in which the torque transmission element  66  is disposed, at least partially. 
     The torque transmission element  66  is disposed with a partial region in the recesses  78 ,  80  of the outer walls  70 ,  72 . The torque transmission element  66  in this case, at least in the partial region disposed in the recesses  78 ,  80 , has an extent, along a rotation axis  82  of the torque transmission element  66 , that closes in a flush manner with one of the outer faces  74 ,  76  and/or with both outer faces  74 ,  76  of the guide unit  18 . In addition, the partial region of the torque transmission element  66  that is disposed in the recesses  78 ,  80  of the outer faces  74 ,  76  of the guide unit  18  has an outer dimension, extending at least substantially perpendicularly in relation to the rotation axis  82  of the torque transmission element  66 , that is at least 0.1 mm smaller than an inner dimension of the recesses  78 ,  80  that extends at least substantially perpendicularly in relation to the rotation axis  82  of the torque transmission element  66 . The partial region of the torque transmission element  66  that is disposed in the recesses  78 ,  80  is disposed, respectively, along a direction running perpendicularly in relation to the rotation axis  82 , at a distance from an edge of the outer walls  70 ,  72  that delimits the respective recess  78 ,  80 . The partial region of the torque transmission element  66  that is disposed in the recesses  78 ,  80  therefore has a clearance within the recesses  78 ,  80 . 
       FIG. 7  shows a detail view of cutter carrying elements  84 ,  86  of the cutting strand  16  of the power-tool parting device  14 . The cutting strand  16  comprises a multiplicity of interconnected cutter carrying elements  84 ,  86 , which are in each case connected to each other by means of a connecting element  88 ,  90  of the cutting strand  16  that closes at least in a substantially flush manner with one of two outer faces  92 ,  94  of one of the interconnected cutter carrying elements  84 ,  86  (cf. also  FIG. 9 ). The connecting elements  88 ,  90  are realized in the form of pins. When the cutting strand  16  is disposed in the guide groove  64 , the outer faces  92 ,  94  run at least substantially parallelwise in relation to the cutting plane of the cutting strand  16 . Persons skilled in the art will select an appropriate number of cutter carrying elements  84 ,  86  for the cutting strand  16  according to the application. The cutter carrying elements  84 ,  86  are each respectively integral with one of the connecting elements  88 ,  90 . The cutter carrying elements  84 ,  86  additionally have a respective connecting recess  96 ,  98 , for receiving one of the connecting elements  88 ,  90  of the interconnected cutter carrying elements  84 ,  86 . The connecting elements  88 ,  90  are guided by means of the guide unit  18  ( FIG. 9 ). In this case, when the cutting strand  16  is in a mounted state, the connecting elements  88 ,  90  are disposed in the guide groove  64 . The connecting elements  88 ,  90 , as viewed in a plane running perpendicularly in relation to the cutting plane, can be supported on two side walls  100 ,  102  of the guide groove  64 . The side walls  100 ,  102  delimit the guide groove  64  along a direction running perpendicularly in relation to the cutting plane. In addition, the side walls  100 ,  102  of the guide groove  64 , as viewed in the cutting plane, starting from the guide unit  18 , extend outwardly, perpendicularly in relation to the cutting direction  40  of the cutting strand  16 . 
     The cutter carrying elements  84 ,  86  of the cutting strand  16  have a respective drive recess  104 ,  106  that, in a mounted state, is in each case disposed on a side  108 ,  110  of the respective cutter carrying element  84 ,  86  that faces toward the torque transmission element  66 . The torque transmission element  66 , in at least one operating state, engages in the drive recesses  104 ,  106 , for the purpose of driving the cutting strand  16 . The torque transmission element  66  in this case is realized as a toothed wheel. The torque transmission element  66  therefore comprises teeth  112 ,  114 , which are provided to engage in the drive recesses  104 ,  106  of the cutter carrying elements  84 ,  86 , in at least one operating state, for the purpose of driving the cutting strand  16 . In addition, the sides  108 ,  110  of the cutter carrying elements  84 ,  86  that face toward the torque transmission element  66  are realized in the form of an arc. The sides  108 ,  110  of the cutter carrying elements  84 ,  86  that face toward the torque transmission element  66  when in a mounted state are each realized in the form of an arc in partial regions  116 ,  118 ,  120 ,  122 , as viewed between a central axis  124  of the respective connecting element  86 ,  88  and a central axis  126 ,  128  of the respective connecting recess  96 ,  98 . The arc-shaped partial regions  116 ,  118 ,  120 ,  122  are realized such that in each case they adjoin the drive recesses  104 ,  106 , in which the torque transmission element  66  engages. In this case, the arc-shaped partial regions  116 ,  118 ,  120 ,  122  have a radius corresponding to a radius of a course of the guide groove  64  at the convex ends  58 ,  60 . The partial regions  116 ,  118 ,  120 ,  122  are concave in form ( FIG. 8 ). 
     The cutting strand  16  additionally has cutting elements  130 ,  132 . The cutting elements  130 ,  132  are integral, respectively, with one of the cutter carrying elements  84 ,  86 . The number of cutting elements  130 ,  132  depends on the number of cutter carrying elements  84 ,  86 . Persons skilled in the art will select a suitable number of cutting elements  130 ,  132  according to the number of cutter carrying elements  84 ,  86 . The cutting elements  130 ,  132  are provided to effect parting-off and/or removal of material particles of a workpiece that is to be worked (not represented in greater detail here). The cutting elements  130 ,  132  can be realized, for example, as full cutters, half cutters or as other kinds of cutters, considered appropriate by persons skilled in the art, which are provided to effect parting-off and/or removal of material particles of a workpiece that is to be worked. The cutting strand  16  is continuous. The cutting strand  16  is thus realized as a cutting chain. The cutter carrying elements  84 ,  86  in this case are realized as chain links, which are connected to each other by means of the pin-type connecting elements  88 ,  90 . It is also conceivable, however, for the cutting strand  16 , the cutter carrying elements  84 ,  86  and/or the connecting elements  88 ,  90  to be of another design, considered appropriate by persons skilled in the art.