Abstract:
The invention relates to a portable power tool system comprising a portable power tool ( 12   a - n ), especially an angle grinder, a protective hood unit ( 14   a - n ) and a protective hood anti-rotation lock ( 16   a - n ) for providing anti-rotational locking between the protective hood unit ( 14   a - n ) and the portable power tool ( 12   a - n ) in the event of a breakage of a tool ( 18   a - n ). According to the invention, the protective hood anti-rotation lock ( 16   a - n ) is adapted to provide anti-rotational locking between the protective hood unit ( 14   a - n ) and the portable power tool ( 12   a - n ) while at the same time securing the protective hood unit ( 14   a - n ) to the portable power tool ( 12   a - n ) in a working position of the protective hood unit ( 14   a - n ).

Description:
CROSS-REFERENCE TO A RELATED APPLICATION 
     The invention described and claimed hereinbelow is also described in German Patent Application DE 10 2006 053.4 filed on Nov. 13, 2006. The German Patent Application, whose subject matter is incorporated here by reference, provides the basis for a claim of priority of invention under 35 U.S.C. 119 (a)-(d). 
     BACKGROUND OF THE INVENTION 
     The present invention relates to a hand-held power tool system. 
     Publication EP 812 657 A1 makes known an angle grinder with an adjustable guard. In that case, the guard is adjustable in a rotating manner on a connection piece of a flange of the angle grinder, and is supported such that it may be detachably attached using a single form-fit locking means. The spindle of the angle grinder passes through the center of the flange. A cutting disk and/or grinding disk are/is installed on the free end of the spindle in a clampable, rotationally drivable manner for cutting and machining work pieces, which are partially enclosed by the guard. The guard must be positioned in a rotationally adjustable manner on the hand-held power tool such that the region of the grinding disk that faces the user is enclosed by the guard. At the same time, a region of the grinding disk that points away from the user extends past the flange, radially relative to the work piece engagement. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a hand-held power tool system with a hand-held power tool, in particular an angle grinder, a guard unit, and a guard anti-rotation lock unit, which is provided to prevent rotation between the guard unit and the hand-held power tool during breakdown of a tool. 
     It is provided that the guard anti-rotation lock unit is provided to prevent rotation between the guard unit and the hand-held power tool at the same time as the guard unit is being attached to the hand-held power tool when the guard unit is in a working position. In this context, “provided” is intended to mean, in particular, specially equipped and/or designed. In addition, the expression “working position of the guard unit” refers, in particular, to a position of the guard unit in which the guard unit is non-rotatably located on the hand-held power tool during regular working operation of the hand-held power tool, and a guard of the guard unit ensures advantageous protection for an operator against contact with a tool, in particular a disk-shaped, rotatably drivable tool, and/or from machining residue that is slung in the direction of the operator. In addition, a “breakdown of the tool” is intended to mean, in particular, a tool that bursts during operation of the hand-held power tool, in which case individual tool parts may be slung outwardly due to rotation of the tool. Due to the inventive design of the hand-held power tool system, it is possible to protect an operator of the hand-held power tool—in an effective and, in particular, reliable manner—from a tool that rotates during operation of the hand-held power tool, and, in particular, from pieces of the tool that are slung in the direction of the operator if the tool becomes damaged, e.g., if the tool should burst. Advantageously, a sizing of the guard anti-rotation lock unit is designed to absorb forces that occur when the tool becomes damaged, these forces being transferred from pieces of the burst tool that strike the guard unit to the guard unit itself, when the guard unit is in an anti-rotation lock position with the hand-held power tool. Advantageously, a position of the guard unit during breakdown of the tool is preferably maintained via the guard anti-rotation lock unit and an operation of the guard unit. In addition, in particular, a protective position and/or an anti-rotation lock position of the guard unit is designed as the working position of the guard unit, thereby making it possible for the anti-rotation lock position to be attained by an operator of the hand-held power tool system using a simple design. Particularly advantageously, the guard anti-rotation lock element is located, at least partially, on guard and/or a closing unit of the guard unit. A “closing unit” refers, in particular, to a unit that is preferably provided to attach the guard unit to the hand-held power tool, and that includes at least one closing element, e.g., a clamping band, a screw, a closing lever, etch, it being possible to attach the guard unit to the hand-held power tool using the closing unit in a form-fit and/or non-positive manner. In addition, “located” is intended to mean, in particular, that the guard anti-rotation lock unit and the guard and/or the closing unit include a common installation unit and that they may be installed in an operating position on the hand-held power tool in the same installation procedure. 
     A particularly stable anti-rotation lock between the guard unit and the hand-held power tool may be attained using a simple design when the guard anti-rotation lock includes a non-positive connection unit and/or form-fit connection unit, which are/is provided to establish a non-positive and/or form-fit connection between the guard unit and the hand-held power tool. 
     It is also provided that the guard anti-rotation lock unit includes at least one anti-rotation lock element located on the guard unit, and an anti-rotation lock element located on the hand-held power tool, which are located at least partially in an anti-rotation lock position when the guard unit is in the working position, thereby making it advantageously possible to realize an effective anti-rotation lock when the guard unit is in a working position, thereby providing a high standard of safety for an operator. 
     If, in addition, the anti-rotation lock element is formed at least partially by a detent element that is provided to block a motion of the guard unit in at least one direction, it is advantageously possible to prevent rotation of the guard unit—in particular if a tool should burst—and to make it easier, at least partially, for an operator of the hand-held power tool system to change the position of the guard unit. Preferably, a blocking direction of the detent element corresponds to a rotational direction of a tool, thereby making it possible for an advantageous anti-rotation lock to be attained if the tool should break down. 
     Furthermore, additional components, installation space, assembly effort and costs may be advantageously saved when the anti-rotation lock element is designed as a single piece with a closing unit and/or a guard of the guard unit. The term “single piece” is intended to mean, in particular, one piece, cast, and/or designed as one component. 
     When the closing unit includes at least one closing element on which the anti-rotation lock element is located, it is possible to provide an operator with an anti-rotation lock of the guard unit that is easy to install. 
     A particularly easy means for attaching and removing the guard unit to/from the hand-held power tool may be advantageously attained when the anti-rotation lock element is movably supported on a closing unit and/or a guard of the guard unit. The anti-rotation lock element is preferably located such that it may be moved manually by an operator to release the anti-rotation lock position into an unlocked position. This may be attained in a particularly advantageous manner when the anti-rotation lock element is supported on the closing unit and/or on the guard such that it may move at least partially around a swivel axis. 
     In an alternative embodiment of the present invention, it is provided that the guard anti-rotation lock unit includes at least one lever element on which the anti-rotation lock element is at least partially located, by way of which the anti-rotation lock element may be advantageously moved into an anti-rotation lock position and/or into an inactive position using the lever element. Particularly advantageously, the lever element is rotatably supported on the hand-held power tool and/or the guard unit. 
     It is further provided that the guard anti-rotation lock unit includes at least one moving element that moves the anti-rotation lock element into an anti-rotation lock position when the guard unit reaches its working position, thereby resulting in an at least partially automatic fixing mechanism or moving mechanism that is independent of an operator in order to attain an anti-rotation lock position of the anti-rotation lock element and result in in a high safety standard for the operator independently of a manual actuation by the operator of the guard anti-rotation lock unit. The moving element is advantageously designed as a spring element and/or further moving elements that appear reasonable to one skilled in the technical art, e.g., a moving element designed as a magnet. 
     In an advantageous refinement of the present invention, it is provided that the guard anti-rotation lock unit includes at least one release element, which is provided to move the anti-rotation lock element out of the anti-rotation lock position. As a result, a means for advantageously removing the guard unit after a working process or after operation of the hand-held machine system may be attained. The release element is advantageously supported on the guard unit such that it is at least partially movable—the release element being preloaded in particular with spring loading in the anti-rotation lock position—thereby making it possible to install the release element in a compact manner and to advantageously secure the anti-rotation lock element in the anti-rotation lock position. 
     Furthermore, additional components, installation space, assembly effort and costs may be advantageously saved when the release element is designed at least partially as a single piece with the locking unit. 
     Advantageously, the hand-held power tool includes a receiving unit for accommodating a tool, on which the anti-rotation lock element is located, thereby making it possible, in particular, to provide a space-saving, compact guard anti-rotation lock unit by the fact that the anti-rotation lock element of the hand-held power tool is located on a component that is preferably located such that it has direct contact with the guard unit when the guard unit is in a working position. 
     It is also provided that the anti-rotation lock element is movably located on the receiving unit, by way of which a particularly easy means for attaching and removing the guard unit to the hand-held power tool may be advantageously attained. 
     Preferably, additional components, installation space, assembly effort and costs may also be saved when the anti-rotation lock element located on the receiving unit is designed at least partially as a single piece with the receiving unit. 
     When the guard anti-rotation lock unit includes at least two anti-rotation lock elements, which are located one after the other in the circumferential direction on the guard unit, and/or at least two anti-rotation lock elements, which are located one after the other in a circumferential direction on the hand-held power tool, in particular on its receiving unit, it is possible to attain a reusable form-fit and/or non-positive connection between the guard unit and the hand-held power tool, and/or the guard unit may be installed on the hand-held power tool in different positions along the circumferential direction in a non-rotating manner, in particular if a tool should burst. The term “circumferential direction” is intended to mean, in particular, a circumferential direction of the guard unit, which is oriented essentially parallel to a direction of rotation of the tool when the guard unit is in an installed state. 
     Particularly advantageously, the present invention includes a hand-held power tool for a rotating, preferably disk-shaped tool, with a machine housing that includes a flange and/or a machine neck, on which a guard—that is composed of sheet metal in particular—is detachably clampable in order to cover the tool. The guard includes a guard body, which is composed of a circular, disk-shaped piece, in particular with an outer edge located at a right angle thereto, and with a central, circular recess, on the edge of which a guard connection piece and/or collar is formed and that includes an annular clamping band that may be tightened using a clamping means. An anti-rotation lock that acts between the machine neck and the guard is located between the guard and the machine neck and is designed as a profiled structure. The guard may be repeatedly coupled via the clamping band and/or the clamping means in its clamping position in a form-fit and/or non-positive manner with the machine neck, and is therefore capable of being fixed in a non-rotatable position and, to attain a release position, may be disengaged from the form-fit and/or non-positive connection, so that the guard may then be adjusted in a rotational manner. 
     Further advantages result from the description of the drawing, below. Exemplary embodiments of the present invention are shown in the drawing. The drawing, the description, and the claims contain numerous features in combination. One skilled in the art will also advantageously consider the features individually and combine them to form further reasonable combinations. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows an exploded view of an inventive hand-held power tool system, 
         FIGS. 2   a ,  2   b  show the guard anti-rotation lock unit in  FIG. 1  with an anti-rotation lock element that is movably supported on the clamping band, in a schematic partial view from above, in a first variant ( FIG. 2   a ) and in a second variant ( FIG. 2   b ), 
         FIG. 3  shows the guard anti-rotation lock unit with an alternative anti-rotation lock element that is movably supported on the clamping band, in a schematic cross-sectional view, 
         FIGS. 4   a  and  4   b  show a guard anti-rotation lock unit with an anti-rotation lock element designed as a single piece with a clamping band, and with a positioning unit, in a schematic partial view from above ( FIG. 4   a ) and in a schematic side view ( FIG. 4   b ), 
         FIG. 5  shows a guard anti-rotation lock unit with an anti-rotation lock element designed as a single piece with a clamping band, in the region of a closing element, in a schematic partial view, 
         FIG. 6  shows the guard anti-rotation lock unit of an anti-rotation lock element designed as a single piece with a closing element, in a schematic partial view, 
         FIGS. 7   a ,  7   b ,  7   c  show the hand-held power tool system with a positioning unit and the guard anti-rotation lock unit, and a closing unit designed as an alternative to that shown in  FIG. 6 , and in a schematic partial view ( FIG. 7   a ), in a side view ( FIG. 7   b ), and in a further alternative embodiment, in a side view ( FIG. 7   c ), 
         FIGS. 8   a ,  8   b  show a guard anti-rotation lock unit with an anti-rotation lock element that is movably supported on a closing element, in a schematic side view ( FIG. 8   a ), and in a perspective view ( FIG. 8   b ), 
         FIG. 9  shows a guard anti-rotation lock unit with an anti-rotation lock element that is movably supported on a receiving unit, in an exploded view, 
         FIG. 10  shows a guard anti-rotation lock unit, which is located as a single piece on a guard of a guard unit, in a perspective view, 
         FIG. 11  shows a guard anti-rotation lock unit with anti-rotation lock elements designed as a single piece with a guard, which is held in an anti-rotation lock position using a spring element, in a schematic partial view, 
         FIG. 12  shows a guard anti-rotation lock unit with an anti-rotation lock that is based on a non-positive connection, in an exploded view, 
         FIGS. 13   a  and  13   b  show a guard anti-rotation lock unit with a release element located on the guard, in a schematic cross-sectional view ( FIG. 13   a ), and in a perspective partial view ( FIG. 13   b ), 
         FIG. 14  shows a guard anti-rotation lock unit with an anti-rotation lock element and a release element located on the guard, in a schematic top view, and 
         FIG. 15  shows a guard anti-rotation lock unit—that is an alternative to that shown in FIG.  14 —with an anti-rotation lock element and a release element located on the guard, in a schematic top view. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       FIG. 1  shows a hand-held power tool system  10   a  with a hand-held power tool  12   a  designed as an angle grinder, and with a guard unit  14   a  and a guard anti-rotation lock unit  16   a . To accommodate guard unit  14   a  and/or a tool  18   a , which is designed as a cutting disk, hand-held power tool  12   a  includes a receiving unit  60   a , which is screwed together with hand-held power tool housing  66   a  of hand-held power tool  12   a . A drive shaft  70   a  extends out of receiving unit  60   a  on a side  68   a  facing away from hand-held power tool housing  66   a . Drive shaft  70   a  is connectable at its free end  72   a  with disk-shaped tool  18   a  and is rotationally drivable around an axis  74   a . Guard unit  14   a  includes a guard  22   a  and a closing unit  20   a , on which guard anti-rotation lock unit  16   a  is located. Guard  22   a  extends around an angular range of tool  18   a  of approximately 180° and, to this end, includes a semi-disk shaped guard body  76   a  and a guard edge  78   a , which is initially oriented perpendicularly to semi-disk shaped body  76   a  and is finally oriented parallel to semi-disk shaped guard body  76   a , inwardly in a radial direction  80   a . Guard anti-rotation lock unit  16   a  is provided to prevent rotation between guard unit  14   a  and hand-held power tool  12   a  or receiving unit  60   a  during breakdown of tool  18   a , e.g., if tool  18   a  should burst. The anti-rotation lock between guard unit  14   a  and hand-held power tool  12   a  takes place at the same time as guard unit  14   a  is attached to hand-held power tool  12   a , when guard unit  14   a  is in a working position. 
     Guard unit  22   a  also includes a guard collar  82   a , which is oriented essentially perpendicularly to semi-disk shaped guard body  76   a  ( FIGS. 1 ,  2   a , and  2   b ). Guard collar  82   a  is enclosed outwardly in radial direction  80   a  by a clamping band  84   a  of closing unit  20   a . Guard collar  82   a  and clamping band  84   a  are interconnected via a welded connection. Guard collar  82   a —together with clamping band  84   a —is provided to attach guard unit  14   a  to hand-held power tool  12   a  and/or to receiving unit  60   a , which includes a cylindrical receiving flange  86   a  for this purpose. Along a circumferential direction  62   a ,  64   a  of clamping band  84   a , clamping band  84   a  includes two end regions  88   a ,  90   a  in a region that faces away from guard  22   a  and extends outwardly in radial direction  80   a . End regions  88   a ,  90   a  each include a recess  92   a , through which a clamping element  46   a —designed as a clamping screw—of closing unit  20   a  extends. The clamping screw may be fastened in recesses  92   a  of clamping band  84   a  using a nut  94   a . Guard  22   a  is attached in a working position to receiving unit  60   a  and/or on receiving flange  86   a  via closing unit  20   a  using a frictional connection between guard collar  82   a  and clamping band  84   a  and receiving flange  86   a , so that guard unit  14   a  is positioned in a non-rotatable manner during regular operation of hand-held power tool  10   a . In an alternative design of the closing unit, it is basically feasible to use—instead of the clamping screw—further closing elements  46   a , e.g., a clamping lever and/or form-fit elements, etc. 
     Guard anti-rotation lock unit  16   a  prevents guard unit  14   a  from accidentally rotating if tool  18   a  should become damaged, in particular if tool  18   a  should burst. To this end, guard anti-rotation lock unit  16   a  includes a form-fit unit  26   a , which is provided to establish a form-fit connection between guard unit  14   a  and receiving flange  86   a  of hand-held power tool  12   a , a form-fit connection being established at the same time that guard unit  14   a  is attached to receiving flange  86   a  in a working position. To establish the form-fit connection, form-fit unit  26   a  and/or guard anti-rotation lock unit  16   a  include three anti-rotation lock elements  28   a ,  30   a ,  32   a —each of which is designed as a form-fit element, and which are located on clamping band  84   a  of closing unit  20   a —and several anti-rotation lock elements  34   a ,  36   a  formed by form-fit elements, and which are designed as a single piece with receiving unit  60   a . Anti-rotation lock elements  34   a ,  36   a  located on receiving unit  60   a  are designed as detent recesses, and they are located one after the other in circumferential direction  62   a ,  64   a  around receiving flange  60   a . Anti-rotation lock elements  34   a ,  36   a  are designed open in a direction  96   a  that extends away from receiving unit  60   a  in the direction of tool  18   a  and parallel to axis  74   a , and which are located on a main element  98   a  of receiving unit  60   a , which is oriented essentially perpendicularly to axis  74   a . The location of anti-rotation lock elements  34   a ,  36   a  makes it possible to attach guard unit  14   a  to hand-held power tool  12   a  in different working positions in circumferential direction  62   a ,  64   a.    
     The three anti-rotation lock elements  28   a ,  30   a ,  32   a  of guard unit  14   a  are located one after the other in circumferential direction  62   a ,  64   a , and are designed as detent elements  38   a ,  40   a ,  42   a , which block a motion of guard unit  14   a  in one direction, when guard unit  14   a  is in an installed state ( FIG. 2   a ). A blocking direction is a rotational direction of tool  18   a  that ensures that, if tool  18   a  should burst, guard unit  14   a  remains attached in its protective position. To this end, detent elements  38   a ,  40   a ,  42   a  are cut at an angle and have an essentially triangular cross-sectional area, so that, when a fastening means and/or the clamping screw are/is loosened, guard  22   a  may be rotated in a direction that is opposite to the rotational direction of tool  18   a  during operation of hand-held power tool  12   a  ( FIG. 2   a ). As an alternative, anti-rotation lock elements  28   a ,  30   a ,  32   a  in  FIG. 2   b  are provided with an essentially rectangular cross-sectional area that serves to prevent guard  22   a  from rotating in either direction of circumferential direction  62   a ,  64   a.    
     Anti-rotation lock elements  28   a ,  30   a ,  32   a  are movably supported on clamping band  84   a . To this end, guard anti-rotation lock unit  16   a  includes a lever element  52   a  that is located on clamping band  84   a  such that it may swivel around swivel axis  50   a . When guard unit  14   a  is installed on hand-held power tool  12   a , swivel axis  50   a  of lever element  52   a  is oriented essentially perpendicular to axis  74   a  and extends away from axis  74   a  in a radial direction  80   a . Anti-rotation lock elements  28   a ,  30   a ,  32   a  are located on an end  100   a  of lever element  52   a  facing away from swivel axis  50   a  and extend in the manner of projections along a swivel direction  102   a  around swivel axis  50   a  on lever element  52   a . When guard unit  14   a  is in a working position, anti-rotation lock elements  28   a ,  30   a ,  32   a  are located on a side of lever element  52   a  facing anti-rotation lock elements  34   a ,  36   a.    
     Guard anti-rotation lock unit  16   a  also includes a moving element  54   a , which is designed as a spring element  56   a  and moves lever element  52   a  and/or anti-rotation lock elements  28   a ,  30   a ,  32   a  into an anti-rotation lock position when guard unit  14   a  reaches a working position, during installation on hand-held power tool  12   a . As a result, anti-rotation lock elements  28   a ,  30   a ,  32   a  are always in the anti-rotation lock position as soon as guard unit  14   a  is installed in the working position. Spring element  56   a  bears against a support element  104   a  of clamping band  84   a . Support element  104   a  is located along axis  74   a  on a region  106   a  facing away from anti-rotation lock elements  28   a ,  30   a ,  32   a , and a spring force of lever element  52   a  presses along axis  74   a  in a direction  108   a  facing away from tool  18   a . To release the anti-rotation lock position of anti-rotation lock elements  28   a ,  30   a ,  32   a , lever element  52   a  includes a release element  58   a , which is designed as a tab, and which is located on end  100   a  of lever element  52   a  facing away from swivel axis  50   a  and extends outwardly on lever element  52   a  along radial direction  80   a , so that an operator may move lever element  52   a —using the tab—along with anti-rotation lock elements  28   a ,  30   a ,  32   a , out of the anti-rotation lock position along swivel direction  102   a . It is also feasible, in principle, for closing unit  20   a  to be closable only when anti-rotation lock elements  28   a ,  30   a ,  32   a  are located in an anti-rotation lock position. To remove and/or change the position of guard unit  14   a  in circumferential direction  62   a ,  64   a , closing unit  20   a  must be released and, if rotation is locked in both directions, guard anti-rotation lock unit  16   a  must also be moved out of its anti-rotation lock position, so that anti-rotation lock elements  28   a ,  30   a ,  32   a  are disengaged from recesses in receiving unit  60   a  and guard unit  14   a  may rotate and/or be removed relative to hand-held power tool  12   a.    
     Hand-held power tool system  10   a  also includes a coding device  110   a , which is provided to prevent tools  18   a  and/or tools  18   a  together with guard unit  14   a  from being installed on unsuitable hand-held power tools  12   a . To this end, clamping band  84   a  includes a coding element  112   a  of coding device  110   a , which is designed as a single piece with clamping band  84   a . Coding device  112   a  is designed as a pressed-out region that extends inwardly in radial direction  80   a  and has a rectangular shape. Correspondingly, receiving flange  86   a  includes a coding element  114   a  of coding device  110   a , which is designed as a recess into which coding means  112   a  of clamping band  84   a  may be inserted when guard unit  14   a  is installed on hand-held power tool  12   a . After guard unit  14   a  has been inserted onto receiving unit  60   a , guard unit  14   a  may be rotated into a working position. To this end, receiving flange  86   a  includes a groove  116   a  that extends in circumferential direction  62   a ,  64   a , in which coding element  112   a  is guided when guard unit  14   a  is rotated into the working position. 
     Alternative exemplary embodiments are shown in  FIGS. 3 through 15 . Components, features, and functions that are essentially the same are labelled with the same reference numerals. To distinguish the exemplary embodiments from each other, the reference numerals of the exemplary embodiments are appended with the letters a through n. The description below is essentially limited to the differences from the exemplary embodiment in  FIGS. 1 and 2 . With regard for the components, features, and functions that remain the same, reference is made to the description of the exemplary embodiment in  FIGS. 1 and 2 . 
       FIG. 3  shows a hand-held power tool system  10   b  in a partial cross section with a receiving unit  60   b  of a hand-held power tool  12   b , and with a clamping band  84   b  of a guard unit  14   b , and a guard anti-rotation lock unit  16   b . Guard anti-rotation lock unit  16   b  is provided to prevent rotation between guard unit  14   b  and hand-held power tool  12   b  at the same as guard unit  14   b  reaches a working position during installation. To this end, guard anti-rotation lock unit  16   b  includes an anti-rotation lock element  28   b  located on clamping band  84   b  of a closing unit  20   b , and several anti-rotation lock elements  34   b ,  36   b  located on receiving unit  60   b . Anti-rotation lock elements  34   b ,  36   b  located on receiving unit  60   b  are designed as recesses, which are located one after the other in a circumferential direction  62   b ,  64   b  on a receiving flange  86   b  of receiving unit  60   b . The recesses extend radially inwardly from a radially outwardly oriented surface  118   b  of receiving flange  86   b . Anti-rotation lock element  28   b  located on closing unit  20   b  is located on a lever element  52   b  of guard anti-rotation lock unit  16   b . Lever element  52   b  is swivelably supported on clamping band  84   b . Swivel axis  50   b  of lever element  52   b  is oriented essentially perpendicularly to a circumferential direction  62   b ,  64   b  of clamping band  84   b . To fix lever element  52   b  together with anti-rotation lock element  28   b  in an anti-rotation lock position, lever element  52   b  bears against clamping band  84   b  via a moving element  54   b  designed as a spring element  56   b . Spring element  56   b  is designed as a tension spring that is located in radial direction  80   b  between clamping band  84   b  and an inward—in radial direction  80   b —surface of lever element  52   b . Lever element  52   b , together with anti-rotation lock element  28   b , is moved and/or pulled inwardly by spring element  56   b  around swivel axis  50   b , and it is brought into an anti-rotation lock position, i.e., in engagement with anti-rotation lock elements  34   b ,  36   b  of receiving flange. Clamping band  84   b  also includes a recess  122   b , through which anti-rotation lock element  28   b  engages with receiving flange  86   b  in an anti-rotation lock position. On an end  120   b  facing away from anti-rotation lock element  28   b , lever element  52   b  includes a release element  58   b  designed as a tab, via which lever element  52   b  may be moved by an operator from its anti-rotation lock position against a spring force of spring element  56   b . An operator may release a clamping closing element  46   b , which is designed as a clamping screw, only after lever element  52   b  has been moved out of its anti-rotation lock position. 
       FIG. 4   a  shows a hand-held power tool system  10   c  with a guard anti-rotation lock unit  16   c , as a partial cross-section, with an anti-rotation lock element  28   c  of a guard unit  14   c  whose design is an alternative to that shown in  FIG. 3 . Guard anti-rotation lock unit  16   c  is provided to prevent rotation between guard unit  14   c  and a not-shown hand-held power tool at the same as guard unit  14   c  reaches a working position during installation. Anti-rotation lock element  28   c  is designed as a hook-shaped detent element  38   c . In addition, detent element  38   c  is designed as a single piece with a clamping band  84   c  of a closing unit  20   c . Detent element  38   c  of clamping band  84   c  is located such that it is bent inwardly. Detent element  38   c  therefore prevents rotation in a manner analogous to that described with reference to  FIG. 2   a  and enables rotation in a direction opposite to a rotational direction of the tool when closing element  46   c —which is designed as a clamping screw—of closing unit  20   c  is loosened. 
     To make it easier for an operator to attach guard unit  14   c  and/or to change the position of installed guard unit  14   c  on a receiving flange, hand-held power tool system  10   c  includes a positioning device  124   c . Guard unit  14   c  includes a positioning element  126   c  of positioning device  124   c , which is designed as a single piece with clamping band  84   c  ( FIGS. 4   a  and  4   b ). Positioning element  126   c  is located in an edge region  128   c  of clamping band  84   a . When guard unit  14   c  is installed, edge region  128   c  faces away from the tool. Positioning element  126   c  is designed as a segment in circumferential direction  62   c ,  64   c . Positioning element  126   c  is punched out of clamping band  84   c  along two sides  130   c ,  132   c  that face clamping band  84   a , and it is located in an end region  134   c  in circumferential direction  62   c ,  64   c  on clamping band  84   c  ( FIG. 4   b ). On a free end  136   c  in circumferential direction  62   c ,  64   c , positioning element  126   c  includes a pressed-out region that extends inwardly in radial direction  80   c  and has a contour that is essentially identical in shape to a contour of a not-shown positioning element of a receiving flange. 
       FIG. 5  shows a hand-held power tool system  10   d  with a guard anti-rotation lock unit  16   d  in a partial cross-sectional view. Guard anti-rotation lock unit  16   d  is provided to prevent rotation between a guard unit  14   d  and a hand-held power tool  12   d —which is not shown in detail—at the same time as guard unit  14   d  reaches a working position during installation. Guard anti-rotation lock unit  16   d  differs from the exemplary embodiment shown in  FIGS. 4   a  and  4   b  in that an anti-rotation lock element  28   d  of guard anti-rotation lock unit  16   d  is located in an end region  90   d —located in circumferential direction  62   d ,  64   d —of a clamping band  84   d  of a closing unit  20   d . Anti-rotation lock element  28   d  is designed as a single piece with clamping band  84   d  and is bent inwardly relative to clamping band  84   d . Guard anti-rotation lock unit  16   d  also includes several anti-rotation lock elements  34   d ,  36   d  designed as a detent recess in a receiving unit  60   d  of hand-held power tool  12   d . Guard anti-rotation lock unit  16   d  functions in a manner analogous to that described with reference to  FIGS. 2   a ,  4   a , and  4   b . Closing unit  20   d  also includes a closing element  46   d ,  48   d  on each of the end regions  88   d ,  90   d  of clamping band  84   d , along circumferential direction  62   d ,  64   d . Closing elements  46   d ,  48   d  are designed as a screw and a closing lever. The screw connects one of the end regions  88   d  of clamping band  84   d  with the clamping lever located on further end region  90   d . The screw is rotatably supported at end region  88   d , and it extends in circumferential direction  64   d  away from end region  88   d  in the direction toward the closing lever to a bearing point and/or a rotation axis  138   d  of the closing lever with end region  90   d . A guard is attached in a working position via closing unit  20   d  on receiving unit  60   d  and/or on receiving flange  86   d  of receiving unit  60   d  via a frictional connection between a guard collar and/or clamping band  84   d  and receiving flange  86   d . In addition, an operator may adjust an effective fastening force using the screw when fastening between guard unit  14   d  and receiving flange  86   f.    
       FIG. 6  shows a partial cross-sectional view of a hand-held power tool system  10   e  with a guard anti-rotation lock unit  16   e . Guard anti-rotation lock unit  16   d  is provided to prevent rotation between a guard unit  14   d  and a hand-held power tool  12   e  not shown in detail at the same time as guard unit  14   e  reaches a working position during installation, and, to this end, includes an anti-rotation lock element  28   e  designed as a detent cam, which is designed as a single piece with a closing element  46   e  of a closing unit  20   e . Closing unit  20   e  is designed as described with reference to  FIG. 5 , with anti-rotation lock element  28   e  being located on a clamping lever and extending—when closing unit  20   e  is in a closed state—inwardly in a radial direction  80   e . When anti-rotation lock element  28   e  is located in an anti-rotation lock position and/or when guard unit  14   e  is installed in a working position on hand-held power tool  12   e , anti-rotation lock element  28   e  extends into one of several anti-rotation lock elements  34   e ,  36   e  designed as recesses, which are located in a receiving flange  86   e  of a receiving unit  60   e  as described with reference to  FIG. 3 . Clamping band  84   e  also includes a recess  122   e , through which anti-rotation lock element  28   e  extends to attain an anti-rotation lock position. 
       FIG. 7   a  shows a partial cross-sectional view of a hand-held power tool system  10   f  with a guard anti-rotation lock unit  16   f . Guard anti-rotation lock unit  16   f  is provided to prevent rotation between a guard unit  14   f  and a hand-held power tool  12   f  not shown in detail at the same time as guard unit  14   f  reaches a working position during installation, and, to this end, includes an anti-rotation lock element  28   f  designed as a detent cam, which is designed as a single piece with a closing element  46   f  of a closing unit  20   f . Closing element  46   f  is designed as a clamping lever, which is rotatably supported at an end region  88   f —designed as an eyelet—of a clamping band  84   f . The clamping lever includes a recess  140   f , through which a further end region  90   f  of clamping band  84   f  extends. End region  90   f  has a contour that increases continually and outwardly, as viewed from clamping band  84   f , so that, when closing unit  20   f  is closed, a clamping band diameter is reduced and an effective non-positive connection may be established between guard unit  14   f  and a receiving unit  60   f . A design of clamping band  84   f  and receiving unit  60   f  to attain an anti-rotation lock position is similar to that described with reference to  FIG. 6 . Hand-held power tool system  10   f  shown in  FIGS. 7   a  and  7   b  also includes a positioning device  124   f , which is designed as described with reference to  FIGS. 4   a  and  4   b.    
       FIG. 7   c  shows an embodiment of a positioning device  124   f  that is an alternative to the design shown in  FIGS. 7   a  and  7   b . A positioning element  126   f  extends on clamping band  84   f  perpendicularly to a circumferential direction  62   f ,  64   f  of clamping band  84   f  and faces away from a tool when guard unit  14   f  is in an installed state. For locking into position, positioning elements  142   f  of positioning device  124   f  that are designed as grooves are located on receiving unit  60   f . Positioning elements  142   f  are located one after the other in a circumferential direction  62   f ,  64   f  around a receiving flange  86   f  on a main element  98   f  of receiving unit  60   f.    
       FIGS. 8   a  and  8   b  show a partial cross-sectional view of a hand-held power tool system log with a guard anti-rotation lock unit  16   g . Guard anti-rotation lock unit  16   g  is provided to prevent rotation between a guard unit  14   g  and a hand-held power tool  12   g  not shown in detail at the same time as guard unit  14   g  reaches a working position during installation, and, to this end, includes an anti-rotation lock element  28   g  designed as a detent cam, which is movably supported on a closing element  46   g  of a closing unit  20   g . To this end, anti-rotation lock element  28   g  includes a recess  144   g , through which closing element  46   g  extends. Closing element  46   g  is designed as a clamping screw, similar to that shown in  FIG. 1 . Motion in an anti-rotation lock position takes place when a guard unit  14   g  is attached in a working position in that anti-rotation lock element  28   g  is moved into the anti-rotation lock position via a frictional connection with the clamping screw ( FIG. 8   b ). As an alternative, a form-fit connection between the clamping screw and anti-rotation lock element  28   g  is also feasible. In addition, a receiving flange  86   g  includes several anti-rotation lock elements  34   g  designed as recesses, only one of which is shown in  FIG. 8   a . The recesses are located in a receiving flange  86   g  along a circumferential direction  62   g ,  64   g , on after the other, in an edge region  146   g  located outwardly in radial direction  80   g.    
       FIG. 9  shows a hand-held power tool system  10   h  with a guard anti-rotation lock unit  16   h , a receiving unit  60   h , and a guard unit  14   h . Guard anti-rotation lock unit  16   h  is provided to prevent rotation between a guard unit  14   h  and a hand-held power tool  12   h  at the same time as guard unit  14   h  reaches a working position during installation, and, to this end, includes an anti-rotation lock element  34   h , which is movably supported on receiving unit  60   h . Anti-rotation lock element  34   h  is located on a main element  98   h  of receiving unit  60   h  and extends outwardly away from a receiving flange  86   h  in a radial direction  80   h . To ensure that guard unit  14   h  remains in an anti-rotation lock position on receiving flange  86   h  when in a working position, anti-rotation lock element  34   h  is held in an anti-rotation lock position by a not-shown spring element. Moreover, anti-rotation lock element  34   h  is designed as a single piece with a lever element  52   h , with which an operator may manually release anti-rotation lock element  34   h  from the anti-rotation lock position. A clamping band  84   h  of a closing unit  20   h  also includes several anti-rotation lock elements  28   h ,  30   h  designed as recesses, which are located one after the other in a circumferential direction  62   h ,  64   h  on clamping band  84   h . When guard unit  14   h  is in an installed state, the recesses are located in an edge region  128   h  of clamping band  84   h  that faces main element  98   h.    
       FIG. 10  shows a hand-held power tool system  10   i  with a guard anti-rotation lock unit  16   i , a receiving unit  60   i —which is shown only partially—and a guard unit  14   i . Guard anti-rotation lock unit  16   i  is provided to prevent rotation between a guard unit  14   i  and a hand-held power tool at the same time as guard unit  14   i  reaches a working position during installation, and, to this end, includes three anti-rotation lock elements  28   i ,  30   i ,  32   i , which are designed as one piece with a guard  22   i  of guard unit  14   i . The three anti-rotation lock elements  28   i ,  30   i ,  32   i  of guard unit  14   i  are designed as toothing, and they are located one after the other in circumferential direction  62   i ,  64   i . The toothing is located on an edge region  148   i  of a guard body  76   i  of guard  22   i  that faces guard collar  82   i , and extend away from guard  22   i  inwardly in radial direction  80   i  within a plane of guard body  76   i , thereby being oriented essentially perpendicularly to a circumferential direction  62   i ,  64   i  of guard collar  82   i . The toothing is formed as a single piece with guard  22   i  using a stamping-bending process. In addition, a receiving flange  86   i  of the hand-held power tool includes several anti-rotation lock elements  34   i ,  36   i , which are designed as form-fit elements and are designed as a single piece with receiving flange  86   i . Anti-rotation lock elements  34   i ,  36   i  located on receiving flange  86   i  form a toothing that extends in the circumferential direction. Anti-rotation lock elements  34   i ,  36   i  are located on a side  68   i  of receiving flange  86   i  in an outer—in radial direction  80   i —edge region  152   i . Side  68   i  faces a tool during operation of the hand-held power tool. As soon as guard unit  14   i  is located in a working position during installation on the hand-held power tool, anti-rotation lock elements  28   i ,  30   i ,  32   i ,  34   i ,  36   i  also engage with each other and/or are located in an anti-rotation lock position, and guard  22   i  is secured against accidentally rotating if a tool should burst during operation. Anti-rotation lock elements  28   i ,  30   i ,  32   i  of guard  22   i  engage in anti-rotation lock elements  34   i ,  36   i  during a procedure of inserting guard unit  14   i  on receiving unit  60   i  in a direction  108   i  of a hand-held power tool housing. 
       FIG. 11  shows a hand-held power tool system  10   j  with a guard anti-rotation lock unit  16   j , a receiving unit  60   j , and a guard unit  14   j . Guard anti-rotation lock unit  16   j  includes a form-fit unit  26   j , which is provided to prevent guard  22   j  from rotating on a hand-held power tool at the same time as guard unit  14   j  is being attached to the hand-held power tool. Several anti-rotation lock elements  28   j  are located on a guard collar  82   j  of guard  22   j  of guard unit  14   j , which extend away from guard collar  82   j  in a direction  150   j  facing away from guard  22   j . Only one of the anti-rotation lock elements  28   j  is shown. In an alternative embodiment of the present invention, anti-rotation lock elements  28   j  may basically also be located on clamping band  84   j , instead of on guard collar  82   j . Anti-rotation lock elements  28   j  are designed as single pieces with guard collar  82   j  and are located one after the other in a circumferential direction on guard collar  82   j . Receiving unit  60   j  also includes several anti-rotation lock elements  34   j , which are designed as single pieces with receiving unit  60   j . Anti-rotation lock elements  34   j  are designed as recesses and are located one after the other in the circumferential direction around a receiving flange  86   j  on a main element  98   j  of receiving unit  60   j . To prevent the anti-rotation lock position of guard  22   j  from accidentally coming loose from the hand-held power tool, receiving unit  60   j  includes an edge element  154   j  in the region of anti-rotation lock elements  34   j . Edge element  154   j  is oriented essentially parallel to a surface  118   j  of receiving flange  86   j  that points in radial direction  80   j , and is designed as a single piece with receiving unit  60   j . In addition, edge element  154   j  is located at a distance from surface  118   j  on receiving unit  60   j . Anti-rotation lock elements  34   j  are located between edge element  154   j  and surface  118   j . On an end  156   j  of edge element  154   j  facing anti-rotation lock elements  34   j , edge element  154   j  includes a support element  158   j , which extends inwardly in a radial direction  80   j . A moving element  54   j , which is designed as a spring element  56   j  and is located on guard unit  14   j , bears against support element  158   j  during installation and when guard unit  14   j  is in a working position. To this end, guard unit  14   j  also includes an edge element  160   j , which extends outwardly from guard collar  82   j  in radial direction  80   j  and is located on an edge region of guard collar  82   j  facing anti-rotation lock elements  34   j . Spring element  56   j  is located on edge element  160   j . To remove guard unit  14   j , it must be lifted, in order to disengage anti-rotation lock elements  28   j ,  34   j , and so that it may be subsequently rotated, thereby separating the two edge elements  154   j ,  160   j  in the circumferential direction, so that guard unit  14   j  may be removed by an operator. 
       FIG. 12  shows a hand-held power tool system  10   k  with a guard anti-rotation lock unit  16   k , a receiving unit  60   k , and a guard unit  14   k . Guard anti-rotation lock unit  16   k  includes a non-positive connection unit  24   k , which is provided to prevent guard  22   k  from rotating on a hand-held power tool at the same time as guard unit  14   k  is being attached to the hand-held power tool. To this end, a receiving unit  60   k  and a guard collar  82   k  each include an anti-rotation lock element  28   k ,  34   k , each of which is designed as a coated surface with a high friction coefficient. It is also basically feasible for the surfaces of guard collar  82   k  and receiving flange  86   k  to have a desired friction coefficient due to the material selected and/or a surface treatment. When guard unit  14   k  is in an installed state and/or a working position, guard unit  14   k  is attached to receiving unit  60   k  in a non-positive manner via a closing unit  20   k . When guard unit  14   k  is in an installed state, the coated surfaces bear against each other, so that, if a tool should burst, an anti-rotation lock results due to a frictional connection between the two coated surfaces and/or between guard unit  14   k  and the hand-held power tool. 
       FIGS. 13   a  and  13   b  show a partial cross-sectional view of a hand-held power tool system  10   l  with a guard anti-rotation lock unit  16   l , a receiving unit  60   l , and a guard unit  14   l . Guard anti-rotation lock unit  16   l  includes a form-fit unit  26   l , which is provided to prevent guard  11   l  from rotating on a hand-held power tool at the same time as guard unit  14   l  is being attached to the hand-held power tool. To this end, receiving unit  60   l  includes several anti-rotation lock elements  34   l ,  36   l  of guard anti-rotation lock unit  16   l , which are located one after the other in circumferential direction  62   l ,  64   l , and which form a toothing and extend away from side  68   l  in an outer—in radial direction  80   l —edge region  146   l . When hand-held power tool  10   l  is in an installed state, side  68   l  faces a tool. A further anti-rotation lock element  28   l , which is designed as a toothing that corresponds to anti-rotation lock elements  34   l ,  36   l  of receiving unit  60   l , is located on guard unit  14   l . Anti-rotation lock element  28   l  is designed as a single piece with a release element  58   l , which is supported on guard  22   l  such that it is movable in radial direction  80   l . Release element  58   l  is integrally formed with an outer contour of guard  22   l . Release element  58   l  is located such that it is separated from a guard edge  78   l  of guard  22   l  in radial direction  80   l , thereby making it possible for release element  58   l  to move into an anti-rotation lock position and/or out of the anti-rotation lock position. For engagement in anti-rotation lock elements  34   l ,  36   l  of receiving unit  60   l  , a guard collar  82   l  includes a recess  162   l , through which release element  58   l  extends, together with anti-rotation lock element  28   l . To move release element  58   l  together with anti-rotation lock element  28   l  into an anti-rotation lock position at the same time as guard  14   l  reaches a working position, and/or to hold it in the anti-rotation lock position, guard anti-rotation lock unit  16   l  includes a moving element  54   l  designed as a spring element  56   l , which presses release element  58   l  inwardly in radial direction  80   l  against a guard collar  82   l . An anti-rotation lock position of anti-rotation lock element  28   l  with anti-rotation lock elements  34   l ,  36   l  of receiving unit  60   l  is reached when release element  58   l  is located in an outer—in radial direction  80   l —end position. To release the anti-rotation lock, an operator presses release element  58   l  inwardly against a spring force of spring element  56   l , and anti-rotation lock element  28   l  of guard unit  14   l  is slid out of engagement with anti-rotation lock elements  34   l ,  36   l  of receiving unit  60   l . The position of guard unit  14   l  on the hand-held power tool may therefore be changed. 
       FIG. 14  shows a hand-held power tool system  10   m  with a guard anti-rotation lock unit  16   m , a receiving unit  60   m , and a guard unit  14   m , in a partial cross-section. Guard anti-rotation lock unit  16   m  includes a form-fit unit  26   m , which is provided to prevent guard  22   m  from rotating on a hand-held power tool at the same time as guard unit  14   m  is being attached to the hand-held power tool. To this end, a receiving unit  60   m  includes several anti-rotation lock elements  34   m ,  36   m  of guard anti-rotation lock unit  16   m , which are located one after the other in circumferential direction  62   m ,  64   m , and which are formed by recesses and are located in an outer—in radial direction  80   m —edge region  146   m . Guard anti-rotation lock unit  16   m  also includes further anti-rotation lock elements  28   m ,  30   m ,  32   m , which are designed as single pieces with a release element  58   m , which is located on a side  164   m  of a guard body  76   m  of a guard  22   m  that faces away from a tool. When guard unit  14   m  is in a working position, release element  58   m  is located tangentially to receiving unit  60   m  on guard  22   m . Anti-rotation lock elements  28   m ,  30   m ,  32   m  extend—on a side  166   m  of release element  58   m  facing receiving unit  60   m —inwardly in radial direction  80   m . Release element  58   m  includes two recesses  168   m , which are designed as slots, by way of which release element  58   m  is supported on guard  22   m  such that it may move inwardly or outwardly. To this end, screws  170   m —which are screwed together with guard  22   m —are supported in recesses  168   m . To move or hold release element  58   m  in an anti-rotation lock position, guard anti-rotation lock unit  16   m  includes a moving element  54   m , which is designed as a spring element  56   m  and bears against guard  22   m . Release element  58   m  extends with both end regions  172   m  beyond guard body  76   m , thereby making it possible for an operator to easily move release element  58   m  out of its anti-rotation lock position. The operator may actuate it on either end region  172   m . A design of anti-rotation lock elements  28   m ,  30   m ,  32   m  of guard unit  14   m  and the recesses of receiving unit  60   m  also makes it possible for guard unit  14   m  to be easily inserted onto the hand-held power tool in that, when one of the anti-rotation lock elements  28   m ,  30   m ,  32   m  of guard unit  14   m  engages, guard  22   m  is centered in the working position with the aid of spring element  56   m.    
       FIG. 15  shows a hand-held power tool system  10   n  that is an alternative to that shown in  FIG. 14 . Hand-held power tool system  10   n  differs from that shown in  FIG. 14  in that a release element  58   n  of a guard anti-rotation lock unit  16   n  is designed as a single piece with an anti-rotation lock element  28   n  and is rotatably supported via a pivot bearing  174   n  on a guard body  76   n  of a guard  22   n . A rotation axis of release element  58   n  is oriented essentially perpendicularly to a guard body  76   m . Release element  58   n  is held—together with anti-rotation lock element  28   m —in an anti-rotation lock position with release unit  60   m  via a moving element  54   m , which is designed as a spring element  56   m .