Abstract:
A guard device for a hand power tool, in the form of a sanding/grinding hand power tool, has a wheel guard enclosing at least part of a rotating tool in a radial direction; a guide for guiding the wheel guard along a work piece, and comprising a fastening device for mounting the wheel guard on the hand power tool, wherein the guide is joined with the wheel guard in torsion-resistant fashion, and the wheel guard is mounted in a fashion that allows it to move relative to the fastening device; and a depth-of-cut stop limiting the relative movement of the wheel guard and fastening device, and being lockable in position with positive engagement in preselected stepped positions.

Description:
BACKGROUND OF THE INVENTION 
   The invention is based on a guard device for a hand power tool, in particular for a sanding/grinding hand power tool, according to the preamble of claim  1 . 
   Guard devices for hand power tools, in particular for angle grinders, are known, the wheel guards of which offer a certain level of protection during sanding/grinding work, but which do not support a sufficient level of dust removal. This is due to the fact that, during operation and in the idle position, the wheel guard covers only part of the side of the tool and, in particular, a sanding disc/grinding wheel of the hand power tool. The removal of sanding/grinding dust using vacuum is therefore only slightly effective, despite the powerful external vacuum cleaners that are typically used 
   ADVANTAGES OF THE INVENTION 
   The invention is based on a guard device for a hand power tool, in particular for a sanding/grinding hand power tool, comprising a wheel guard that is provided to enclose at least part of a rotating tool in the radial direction, and comprising a guide means for guiding the wheel guard along a work piece, as well as a fastening device for mounting the wheel guard on the hand power tool. 
   It is proposed that the guide means are joined with the wheel guard in torsion-resistant fashion, and the wheel guard is mounted in a fashion that allows it to move relative to the fastening device. 
   With a guard device of this type, a tool of a hand power tool, in particular a sanding/grinding hand power tool, can be enclosed by the wheel guard completely or to a predetermined extent, and, in fact, independent of the tool position relative to a work piece. As a result of this, an operator is protected to a large extent from particles that are removed from a work piece by the tool, i.e., sanding/grinding dust in particular. Additionally, sanding/grinding dust removal can be managed particularly effectively and, in most cases, neither an internal ventilator nor an external vacuum cleaner is required to remove dust. Due to the fact that the wheel guard is mounted in a fashion that allows it to move relative to the fastening device, the wheel guard is also mounted in a fashion that allows it to move relative to the tool position. As a result, the wheel guard can always lie on the work piece while the hand power tool is being operated, regardless of how far the tool enters the work piece. The guide means, which are interconnected with the wheel guard in torsion-resistant fashion, thereby guides the wheel guard along the work piece, by way of which it is ensured that the wheel guard bears against the work piece during operation without being able to tilt relative to the guide means. The wheel guard can therefore be held in a position that is constant relative to the surface of the work piece, independent of the depth of penetration of the tool in the work piece. Particles can therefore effectively be prevented from escaping from between the wheel guard and the surface of the work piece. 
   The invention is capable of being used particularly advantageously with a wheel guard for an angle grinder, since an angle grinder is used in mobile fashion and in various positions, e.g., in an overhead position. When the tool is completely enclosed or enclosed to a predetermined extent by the wheel guard, the operator is protected to a large extent from sanding/grinding dust. 
   The wheel guard encloses the tool in essential regions and, in particular, at least partially in the radial direction. In the case of a disc-shaped, rotating tool, at least one segment of the arc of the periphery of the tool is completely enclosed in the radial direction. Particles of the work piece being worked thrown off by the tool, such as sanding/grinding dust, are therefore captured by the wheel guard in the region in which it encloses the tool in the radial direction. Advantageously, the wheel guard encloses at least 120°, in particular at least 180° of the periphery of the tool, in order to capture as much dust as possible. 
   In an advantageous embodiment of the invention, the guide means comprise at least one sliding shoe. The wheel guard can be guided safely on the work piece on a sliding shoe that extends advantageously in the working direction of the tool. When the sliding shoe is designed with a flat bearing surface or bearing edge, the wheel guard is guided particularly safely over a flat work piece. By minimizing the guide means on a glide shoe that is seated tightly on the wheel guard, the wheel guard can be produced in a particularly lightweight and weight-saving fashion. 
   A particularly simple mounting of the wheel guard in a fashion that allows it to move relative to the fastening device is obtained by mounting the wheel guard in a fashion that allows it to swivel relative to the fastening device. The two elements can be interconnected at one center of rotation. 
   A particularly good level of sanding/grinding dust removal can be achieved when the wheel guard—in a state in which it lies on a flat work piece in the operating position—is provided to enclose the tool together with the work piece to an extent that does not depend on the depth of penetration of the tool in the work piece. The work piece can be enclosed entirely or to a predetermined extent, so that, when the tool is pulled out of the work piece, for example, no dust or no additional dust leaves the wheel guard and enters the surroundings. 
   Advantageously, an air-intake opening remains in the wheel guard or between the wheel guard and the work piece, the size of which is independent of the depth of penetration of the tool in the work piece. In this fashion, a constant flow of air—that is independent of the depth of penetration of the tool in the work piece—from the air-intake opening to a dust removal tube, and, therefore, constant dust removal, is made possible. 
   In a preferred embodiment of the invention, the guard device comprises a spring mechanism that presses the wheel guard against a work piece during operation. The wheel guard therefore lies on the work piece via the guide means, so that an undesired slit does not form between the wheel guard and the work piece through which the dust is carried out of the wheel guard. 
   A guard device, the wheel guard of which encloses the tool completely in the axial direction in the idle position, ensures a high level of work safety: an operator is protected effectively against injury caused by the tool. This also applies for a guard device, in the case of which the tool retracts completely into the wheel guard when it exits the work piece. Additionally, such a guard device ensures good protection against the release of sanding/grinding dust or particles. The dust rotating with the tool is drawn into the wheel guard along with the tool retracting into the wheel guard. 
   The wheel guard advantageously encloses two units that are movable relative to each other that, in mutual interplay, comprise an operating position and a tool replacement position, whereby at least one of the units, in the tool replacement position, exposes the tool in the axial direction to an extent that allows a tool to be replaced. With such an embodiment of the wheel guard, easy tool replacement is possible despite the fact that the tool is largely enclosed in the idle position. A design for this that is particularly simple is obtained by the fact that the two units are capable of being swiveled independently of each other around a common center of rotation relative to the fastening device. The two units are connected to the fastening device with a rivet or screw, for example. One of the units is a pivoted cover plate, for example. The arrangement of the pivoted cover plate to cover the axial side of the sanding disc/grinding wheel improves the work safety with the hand power tool and prevents sanding/grinding dust from escaping from the side, which makes it possible to replace the tool more quickly by swiveling the pivoted cover plate around a center of rotation. The pivoted cover plate can be closed particularly reliably and it is easy to open by means of the positive fastening system of the pivoted cover plate with lobes and snap-in tongues that snap in place together. 
   A further advantage is achieved in that the wheel guard comprises a window that allows an operator to see the tool and, in particular, on the side of the tool closest to a work piece. This makes it possible to control the position of the tool in the work piece particularly easily and effectively. 
   Advantageously, the wheel guard comprises an observation slit. It can be formed by means of an opening in the wheel guard, for example, or by means of a slant in a part of the wheel guard. The observation slit oriented toward the narrow side of the sanding disc/grinding wheel ensures a more controlled handling of the angle grinder with the wheel guard, mainly for exact placement of the sanding disc/grinding wheel in mortar joints. Visual control of the tool is particularly enhanced by means of the window in combination with an observation slit. The air-intake opening can be used as an observation slit. The air drawn in through the observation slit causes turbulence that essentially keeps the window free from dust. When the dust is removed from the opposite side of the window, e.g., by a dust removal tube located there, the air turbulence keeps the window essentially free from dust. 
   The guard device preferably comprises a dust removal tube, e.g., for connection to a dust removal device. Particles can be removed from the wheel guard particularly effectively through a dust removal tube. When the dust removal tube is mounted on the wheel guard, the dust removal tube is moved with the wheel guard. The dust removal tube is therefore in a constant position relative to the work piece, by way of which particularly good dust removal is possible. 
   The blow-off effect of the sanding/grinding dust is further improved by means of a damping plate located inside the wheel guard, since the air whirled by the rotating sanding disc/grinding wheel backs up there, and the air stream is directed out to the dust removal tube. The damping plate can be located on the side opposite the dust removal tube and it be integrally molded on the wheel guard, for example. 
   Depth-of-cut can be preselected particularly quickly by means of a depth-of-cut stop that snaps into place with positive engagement by pressing, sliding, or releasing the push button, and a preselected setting cannot be selected accidentally. 

   
     SUMMARY OF THE DRAWINGS 
     Further advantages result from the following description of the drawings. An exemplary embodiment of the invention is presented in the drawings. The drawings, the description, and the claims contain numerous features in combination. One skilled in the art will advantageously consider them individually as well and combine them into reasonable further combinations. 
       FIG. 1  is a top view of a hand power tool having a guard device according to the invention, in the working position, 
       FIG. 2  is a view of the hand power tool in  FIG. 1  from above, 
       FIG. 3  is a view of the hand power tool in  FIG. 1  from the opposite side, 
       FIG. 4  is the view according to  FIG. 3  rotated by 90° around the vertical axis, 
       FIG. 5  is the view according to  FIG. 1  in the idle position, 
       FIG. 6  is the view according to  FIG. 5  from the opposite side, 
       FIG. 7  is the side view of a further exemplary embodiment of a hand power tool having a guard device according to the invention, in the idle position, 
       FIG. 8  is the view according to  FIG. 7  from the opposite side, 
       FIG. 9  is the view according to  FIG. 8  rotated 90° around the longitudinal axis, 
       FIG. 10  is the view according to  FIG. 7  in the working position, 
       FIG. 11  is a detailed view of the dust removal tube according to  FIGS. 7 and 10 , 
       FIG. 12  is a spatial representation according to  FIG. 1 , 
       FIG. 13  is a spatial view from below according to  FIGS. 1 and 2 , 
       FIG. 14  is a view of the adjustable stop for limiting the depth of cut, 
       FIG. 15  is a detailed view of the depth-of-cut stop, 
       FIG. 16  shows a section of the pivoted cover plate, 
       FIG. 17  is a bottom view of the angle grinder wheel guard according to  FIG. 1 , 
       FIG. 18  shows a side shell of the wheel guard as seen from the outside, 
       FIG. 19  shows the housing shell according to  FIG. 18  as seen from the inside, 
       FIG. 20  is a spatial representation of the anterior region of the sanding/grinding machine comprising dust removal tube extending at a slant relative to the sanding tool. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1  is the side view of an angle grinder  20 , the motor housing  22  of which extends substantially upward at a right angle and contains a not-shown motor. 
   As viewed downward at a right angle, a gearbox housing  24  adjoins the motor housing  22 , the driven shaft  26  ( FIG. 13 ) of which said gearbox housing extends at a right angle to the plane of the drawing and has a tool mounted on its exposed end. The tool is a sanding disc/grinding wheel  28 . It rotates in the direction of rotation  29  in the clockwise direction and plunges into a work piece  30 , in which it cuts a groove  32  coming from the right. 
   As shown on the left side, a sliding button  34  of an on-and-off switch is mounted on the motor housing  22 . 
   A guard device  33  is mounted on the angle grinder  20 . It comprises a fastening device and a wheel guard  40 . The fastening device is designed as a swiveling arm  38 . The swiveling arm  38  is mounted via a well-fitting mounting opening  36  ( FIG. 18 ) on a cylindrically-shaped, axial extension of the gearbox housing  24 , i.e., the neck  25 . The swiveling arm  38 , in turn, is mounted on the wheel guard  40  and is capable of being swiveled upward and downward around a center of rotation  42  relative to the wheel guard  40 . The swiveling arm  38  and the wheel guard  40  are reliably guided in opposition to each other by means of a guide bolt  46  seated on the wheel guard  40  in a guide slot  44  of the swiveling arm  38 . As shown on the left side, the swiveling arm  38  has a knob  48  mounted on it, by way of which the angle grinder  20  with the wheel guard  40  can be guided on a work piece  30 . Additionally, the knob  48  is grasped to manually adjust the depth of cut, whereby the swiveling arm  38  can be adjusted upward and downward. The wheel guard  40  is seated on the work piece  30  with a guide means, i.e., a rail  50  designed in the shape of a runner, located on its bottom side. The guide means ensures that the wheel guard  40  remains perpendicular to the surface of the work piece. 
   As shown on the bottom left, the wheel guard  40  has a dust removal tube  52  mounted on it directly adjacent to the rail  50 . Dust created during sanding is removed through said dust removal tube, e.g., via an inserted tube piece and a dust suctioning device attached thereto. The dust removal tube  52  is situated at a 45° angle relative to the axis of rotation of the sanding disc/grinding wheel  28 . 
   As shown on the bottom right, the wheel guard  40  is angled at a slant in the upward direction, so that an observation opening  54  is formed, through which the tool operator can control the engagement of the sanding disc/grinding wheel  28  in the work piece  30  and/or the groove  32 . As shown at the top right, a handle  56  projects out of the wheel guard  40  at an angle, by way of which the unit comprising angle grinder  20  and wheel guard  40  can be comfortably guided along the work piece  30 . 
   A spring mechanism is located between the swiveling arm  38  and the wheel guard  40  at the center of rotation  42 . The spring mechanism comprises a preloaded leg spring  58  that tries to press the swiveling arm  38  upward. As a result, the angle grinder  20  must be moved relative to the wheel guard  40  according to  FIG. 1  in a counterclockwise direction against the spring force of the leg spring  58  in order to reach its working position in which the sanding disc/grinding wheel  28  protrudes downward out of the pass-through slot  73  ( FIG. 17 ) and/or past the rail  50  so that it can penetrate the work piece  30 . 
   If the angle grinder  20  with the wheel guard  40  is lifted off of the work piece  30 , the leg spring  58  pulls the wheel guard  40  downward relative to the swiveling arm  38 , so that the sanding disc/grinding wheel  28  disappears completely inside the wheel guard  40 . 
   The usual method of working with the angle grinder  20  is directed in the advancing direction  57 , so that the movement of the work piece  30  relative to the sanding disc/grinding wheel  28  is opposite to the direction of rotation  29  of the sanding disc/grinding wheel  28 . 
   The view from the top shown in  FIG. 2  shows the slanted arrangement of the handle  56  on the wheel guard  40 , and the slanted extension of the dust removal tube  52 . Moreover, the neck  25  of the gearbox housing  24  is shown, which said neck engages in the mounting opening  36  of the swiveling arm  38 . 
     FIG. 3  shows the angle grinder  20  with wheel guard  40  according to  FIG. 1  from the opposite side, also in the working position, with the sanding disc/grinding wheel  28  protruding far downward. A guide rule  60  is shown in  FIG. 3 , on which the knob  48  is guided and which can be locked in position by rotating it around its longitudinal axis. Furthermore, a depth-of-cut stop  62  is shown below the knob  48 , which said depth-of-cut stop is also capable of being displaced in the guide rule  60  and which is capable of being locked in position with positive engagement in preselected, stepped positions by the press of a button. The depth-of-cut stop  62  is captively secured on the guide rule  60  ( FIGS. 14 ,  15 ). 
   The guard device  33  comprises two units capable of being moved opposite to one another, i.e., the wheel guard  40  and a pivoted cover plate  64 . The pivoted cover plate  64  is located on the opposite side of the swiveling arm  38  and is intended to cover the sanding disc/grinding wheel  68 . The pivoted cover plate  64  is capable of being swiveled together with the wheel guard  40  around the center of rotation  42 . To replace the sanding disc/grinding wheel  28 , the pivoted cover plate  64  is swiveled toward the upper left—as viewed in this drawing—from the operating position into a tool replacement position. In this outwardly swiveled tool replacement position, the exposed end of the driven shaft  26  and/or the retaining nut  27  ( FIG. 13 ) are easily accessible, so that, after the retaining nut  27  is loosened, the sanding disc/grinding wheel  28  can be removed in the axial direction out of the plane of the drawing. 
   In its lower region, the pivoted cover plate  64  comprises a window  66  in a rectangular opening. Located between the window  66  and the rail  50  is a lateral air-intake opening  68  through which air can pass that replaces the air blown out by the rotating sanding disc/grinding wheel  28  to remove sanding/grinding dust. Relative to the sanding disc/grinding wheel  28 , the air-intake opening  68  is located opposite from the dust removal tube  52 . In a state lying on the flat work piece  30  in the operating position, the air-intake opening  68  has a size that does not depend on the depth of penetration of the sanding disc/grinding wheel  68  in the work piece  30 , since the rail  50 —which, together with the wheel guard  40 , borders the air-intake opening  68 —always lies flat on the work piece  30  independent of the depth of penetration of the sanding disc/grinding wheel  28  in the work piece  30 . 
   The window  66  is inserted in frame segments  70  fastened to the pivoted cover plate  64 , and it engages with the pivoted cover plate  64  in captive fashion with a snap-in tongue  72  extending above it. 
     FIG. 4  shows a side view, rotated by 90°, of the angle grinder  20  according to  FIG. 3 , whereby, in contrast to the preceding figures, the design of the guide rule  60  comprising a central slot  61 —for swiveling the knob  48  vertically and/or for moving the depth-of-cut stop  62  with its push button  63 —is shown. The sanding disc/grinding wheel  28  is also shown penetrating the groove  32 , which said groove is designed as a mortar joint. The rest of the details explained hereinabove are labelled with reference numerals but will not be explained once more. 
     FIG. 5  shows the angle grinder  20  according to  FIG. 1  with the wheel guard  40  in the idle position, in which the sanding disc/grinding wheel  28  has disappeared inside the wheel guard  40 , because the swiveling arm  38  has been moved upward relative to the wheel guard  40 . This is made particularly clear when the relative position of the guide bolt  46  to the guide slot  44  according to  FIG. 5  is compared with said relative position of the guide bolt to the guide slot in FIG.  1 . 
     FIG. 6  shows how the sanding disc/grinding wheel  28 —located behind the rail  50 —is, positioned within the contour of the wheel guard  40 . 
   In  FIGS. 5 and 6 , the idle position of the wheel guard  40  is recognizable by the fact that the knob  48 —as viewed here—is seated against the upper stop of the guide rule  60 . 
     FIGS. 7 and 8  show an exemplary embodiment that is slightly modified as compared with  FIGS. 1 through 6 , comprising a guard device  133 , in the case of which a dust removal tube  152  projecting out of the wheel guard  140  at a right angle is provided, which said dust removal tube is provided for suctioning purposes using a separate vacuum cleaner. Moreover, an elongated, stem-like handle  156  is attached directly to the angle grinder  120  in order to make two-handed operation of the angle grinder  120  possible, whereby one hand can grasp the handle  156 , and the other hand can grasp the motor housing  122 . Moreover, the swiveling arm  138  is provided with a knurled nut  148  instead of a knob, with which said knurled nut the preselected depth of cut can be adjusted. 
   Located on the underside of the wheel guard  140  is a rail  150  for guidance on a work piece  30  shown in FIG.  10 . 
     FIG. 8  shows the view according to  FIG. 7  from the opposite side, whereby, in contrast to  FIG. 3  of the first exemplary embodiment, the window  166  is capable of being secured by means of a knurled nut. 
     FIGS. 7 and 8  show the angle grinder  120  with the wheel guard  140  in the idle position, i.e., with the sanding disc/grinding wheel  28  drawn into the wheel guard  140 , while  FIGS. 9 and 10  show the same angle grinder  120  in the working position, i.e., with the sanding disc/grinding wheel  28  protruding below the rail  150 . 
     FIG. 9  clearly shows a collet  123  that clamps a collar of the wheel guard  140  tightly against the neck  125  of the angle grinder  120 . The wheel guard  140  is easy to remove by loosening a hexagon bolt and opening the collet  123  away from the neck  125  of the angle grinder  120  if the sanding disc/grinding wheel  28  was previously removed. Also shown are the knurled nut  167  for holding the pivoted cover plate  164  in position against the wheel guard  140 , the knurled nut  148  for setting and releasing the preselected depth of cut, and the depth-of-cut stop capable of being adjusted using the knurled nut  162 . 
     FIG. 9  clearly shows the leg spring  158 , with which the angle grinder  120  is automatically moved relative to the wheel guard  140  around the center of rotation  142  into the idle position. Also shown is a suction tube  151  for connection to a vacuum cleaner, with which the sanding/grinding dust can be effectively removed. 
     FIG. 10  shows the angle grinder  120  in the working position, whereby sanding/grinding dust is thrown in the direction of rotation  29  of the sanding disc/grinding wheel  28  tangentially from the point where the sanding disc/grinding wheel  28  exits the work piece  30  and against the interior wall of the dust removal tube  152 , and from there, it is capable of being suctioned off easily via the suction tube  151 . 
     FIG. 11  shows a detained view of the dust removal tube  152  in its position relative to the sanding disc/grinding wheel  28 . One can see that the radially outermost region of the sanding disc/grinding wheel  28  extends into an opening  174  of the dust removal tube  152 . Part of the dust removal tube  152  therefore penetrates the planes—imagined to continue endlessly—of the two flat sides of the sanding disc/grinding wheel  28 . The opening  174  is designed in such a fashion that part of the dust removal tube  152  reaches behind the sanding disc/grinding wheel  28 . The opening  174  is therefore designed in the shape of a slot. 
   The conveying air stream produced by the sanding disc/grinding wheel  28 —together with dust particles—meets the bent surface of the part of the dust removal tube  152  that penetrates the planes of the two flat sides of the sanding disc/grinding wheel  28 , as indicated by the arrows. The conveying air stream with the sanding/grinding dust meeting this impact surface at a high rate of speed is further directed into the dust removal tube  152  in such a fashion that it executes a cyclone-like vortex motion in the dust removal tube. The conveying air and dust stream set into rotational motion in this fashion has sufficient kinetic energy to exit the dust removal tube  152  on its side furthest from the angle grinder  20  under its own power. A vacuum cleaner can be installed downstream for safety reasons, however, to prevent the dust removal tube  152  from becoming blocked in certain working positions of the angle grinder  120 . 
     FIG. 12  shows a side view of a further exemplary embodiment, the design of which essentially matches that of the angle grinder  20  shown in  FIGS. 1 through 4 . The only differences are that the stem-like handle  56  is screwed directly onto the gearbox housing  24  of the angle grinder  20 , and the knob is missing. The collet  23  and the locking screw that hold the angle grinder  20  tightly in position relative to the wheel guard  40  are particularly easy to see. 
     FIG. 13  shows a spatial representation nearly parallel to the sanding disc/grinding wheel  28  from the underside of the wheel guard  40 . The embodiment of the rail  50  with a glide shoe  49  is shown particularly clearly. The rail  50  is located in the exit region of the wheel guard  40 , where part of the sanding disc/grinding wheel exits the wheel guard  40  during operation. The glide shoe  49  of the rail  50  constricts the cross section of the exit region of the wheel guard  40 . This helps the air stream in the wheel guard  40  along in the direction toward the dust removal tube  52 . 
   As shown on the left side, a damping plate  76  is located next to the sanding disc/grinding wheel  28 , which said damping plate extends radially very close to the periphery of the sanding disc/grinding wheel  28  and dampens a movement of air caused by the rotating sanding disc/grinding wheel  28  during sanding. As a result, a certain vacuum is produced inside the wheel guard  40 , which said vacuum blows through the dust removal tube  52  and takes any sanding/grinding dust present along with it. 
   The collet  23  with the clamping nut for mounting the wheel guard  40  on the gearbox housing  24  is shown. On the top, the wheel guard  40  is covered horizontally with the pivoted cover plate  64  made of sheet metal, attached to which said pivoted cover plate—as shown on the right side—is a round, projecting swivel grip  65  to be operated using the thumb. 
   As shown on the left side, an arrow indicating the direction of rotation is stamped in the pivoted cover plate  64  that points to the left in the view shown. This is the intended direction of rotation for swiveling the pivoted cover plate  64  upward into its release position to remove the sanding disc/grinding wheel  28 . Additionally, the arrow also indicates the direction of rotation of the sanding disc/grinding wheel  28 . The pivoted cover plate  64  is swung to the left by approximately 180° around the center of rotation  42  so that the sanding disc/grinding wheel  28  can be exposed and replaced after the retaining nut  27  is removed. 
   The frame segments  70  for accommodating the window  66  in the corresponding opening are also clearly shown. 
     FIG. 14  shows the guide rule  60  as a fixed part of the wheel guard  40 , relative to which the swiveling arm  38  can be adjusted via swiveling. The position of the swiveling arm  38  relative to the guide rule  60  can be fixed and/or released using the knurled thumb screw  48 a and/or using the knob  48  shown in  FIGS. 1 through 4  by turning them around their axes. 
   The push button  63  of the depth-of-cut stop  62  can be engaged in the toothed rack-like outer contour  59  by way of a mirror-image profile, and it can be disengaged with spring action by pressing on the push button  63 . If pressure on the push button  63  is released, it automatically engages with its mating profile  79  in the toothed rack-like outer contour  59  in the respective position. The depth-of-cut stop  62  can be fixed in position at any position along the guide rule  60 , so that the swiveling arm  38  with its knurled thumb screw  48   a  can only be swiveled up to said stop. With this, a reproducible depth of cut is established. 
     FIG. 15  shows a detained view of the depth-of-cut stop  62  with its push button  63  and a profile carrier  78  made of sheet metal that forms the mating profile  79  for engaging in the toothed rack-like outer contour  59  of the guide rule  60 . A tab  80  is located on each of the opposite sides of the profile carrier  78 , which said tabs fit in the center slot  61  of the guide rule  60  for guided engagement. The profile carrier  78  is penetrated transversely by a guide bolt  82 , along which it can be moved toward the push button  63  and away from said push button. The push button  63  is preloaded elastically by means of a spiral-coiled spring  83 . 
   The push button  63  and the profile carrier  78  are securely braced against each other, whereby, in the assembled state, the guide rule  60  runs along between the two. The spiral-coil spring  83  with a support disc  84  comes to bear at the top against the guide rule  60  and, when the push button  63  is operated, it moves in an axially spring-loaded fashion relative to the guide rule  60 , so that the profile carrier  78  with its mating profile  79  can disengage from the outer contour  59  of the guide rule  60 . 
     FIG. 16  shows a section of a spatial representation of the swivel grip  65  of the pivoted cover plate  64 . It is formed by part of the pivoted cover plate  64 . As shown on the left, the pivoted cover plate  64  comprises a tab  86  bent outwardly upward, through which a flexible tongue  88  of an L-shaped leaf spring  89  extends, which said leaf spring is interconnected flatly with the rail  50 , i.e., they are riveted together in this case. 
   One of the frame segments  70  into which the window  66  can be inserted is shown at the top. 
   An opening  90  in the pivoted cover plate  64  is shown on the right side, which said opening snaps into place over a detent lobe  92  that extends out of the adjacent side wall of the wheel guard  40 . By swiveling the pivoted cover plate  64  to the right using the swivel grip  65  as viewed here, the tab  86  can glide over the flexible tongue  88 , and the opening  90  can overcome the detent lobe  92 , so that the pivoted cover plate  64  can then be rotated around the center of rotation  42  ( FIG. 13 ) with minimum force. 
     FIG. 17  shows an underside view of the wheel guard  40  with the top view of the runner-like rail  50 . Its surface forms a pass-through slot  73  through which the not-shown sanding disc/grinding wheel  28  can enter and exit. 
   Shown at the bottom is the collet  23  with the pass-through opening  36  for accommodating the neck  25  of the angle grinder  20  (FIG.  1 ). The leg spring  58  is shown at the outer left, which said leg spring tries to swivel the swiveling arm  38  around the center of rotation  42 , while the dust removal tube  52  projects in the lower right-hand side of the drawing. The dust removal tube  52  tapers toward its mouth pointing toward the sanding disc/grinding wheel  28 . As a result, the conveying air stream produced by the sanding disc/grinding wheel  28  flows rapidly in the axial direction of the dust removal tube  52  through the constriction in the mouth of the dust removal tube  52 . It therefore leaves the inside of the wheel guard  40  at great speed, whereby it executes the rotational motion described with FIG.  11 . Due to the widening of the dust removal tube in the direction away from the wheel guard  40 , the air stream develops a suction effect due to its rotation, which said suction effect helps the air to exit the wheel guard and enter the dust removal tube  52 . 
   The wheel guard  40  is covered on the top by the pivoted cover plate  64 , the frame segments  70  of which project upwardly and hold the window  66 . Additionally, the tab  86  is shown on the pivoted cover plate  64  at the top right. 
     FIG. 18  shows a detained view of the stationary, shell-like side part  96  of the wheel guard  40 , to which the welded-on guide rule  60  is attached as shown on the right. 
   The runner-like region of the rail  50  and the dust removal tube  52  can be seen in the upper right. Shown particularly clearly here is the arrangement of the suction tube in the outermost corner of the wheel guard  40 , at the site of origination of the sanding/grinding dust when the angle grinder  20  is used, through which said suction tube any sanding/grinding dust created moves by means of the high natural speed imparted by the sanding disc/grinding wheel  28  in conjunction with the blast air stream produced by the sanding disc/grinding wheel  28  itself. 
   Located approximately in the middle of the side part  96  is the pass-through opening  36 , through which the neck  25  of the angle grinder  20  extends. The pass-through opening  36  is a slot that allows the angle grinder  20  and/or the neck  25  to swivel up and down relative to the wheel guard  40  until the maximum depth of cut is reached. 
     FIG. 19  shows the side part  96  as viewed from the inside, whereby the rail  50 , the dust removal tube  52 , and the guide rule  60  are shown particularly clearly. Moreover, the damper plate  76  and the observation opening  54  are shown on the outermost side of the side part  96 . 
     FIG. 20  is a side view of the wheel guard  40  showing a section in the region of the gearbox housing  24  of the angle grinder  20 . Also shown clearly is the knob  48  for guiding the wheel guard  40  and/or for adjusting a preselected depth of cut and the depth-of-cut stop  62 . Also shown is the dust removal tube  52 , in the circumferential contour of which the sanding disc/grinding wheel  28  passes through the opening  74  with its radially outermost region. 
   
     
       
             
           
             
             
           
         
             
                 
             
             
               Reference Numerals 
             
             
                 
             
           
           
             
                 
             
           
        
         
             
                20 
               Angle 
             
             
                22 
               Motor housing 
             
             
                23 
               Collet 
             
             
                24 
               Gearbox housing 
             
             
                25 
               Neck 
             
             
                26 
               Drive shaft 
             
             
                27 
               Retaining nut 
             
             
                28 
               Sanding disc/grinding wheel 
             
             
                29 
               Direction of rotation 
             
             
                30 
               Work piece 
             
             
                32 
               Groove 
             
             
                33 
               Guard device 
             
             
                34 
               Sliding button 
             
             
                36 
               Mounting opening 
             
             
                38 
               Swiveling arm 
             
             
                40 
               Wheel guard 
             
             
                42 
               Center of rotation 
             
             
                44 
               Guide slot 
             
             
                46 
               Giude bolt 
             
             
                48 
               Knob 
             
             
                 48a 
               Knurled thumb screw 
             
             
                49 
               Glide shoe 
             
             
                50 
               Rail 
             
             
                52 
               Dust removal tube 
             
             
                54 
               Obervation opening 
             
             
                56 
               Handle 
             
             
                57 
               Advancing direction 
             
             
                58 
               Leg spring 
             
             
                59 
               Outer contour 
             
             
                60 
               Guide rule 
             
             
                61 
               Slot 
             
             
                62 
               Depth-of-cut stop 
             
             
                63 
               Push button 
             
             
                64 
               Pivoted cover plate 
             
             
                65 
               Swivel grip 
             
             
                66 
               Window 
             
             
                68 
               Air-intake opening 
             
             
                70 
               Frame segment 
             
             
                72 
               Snap-in tongue 
             
             
                73 
               Pass-through slot 
             
             
                74 
               Opening 
             
             
                76 
               Damping plate 
             
             
                78 
               Profile carrier 
             
             
                79 
               Mating profile 
             
             
                80 
               Tab 
             
             
                82 
               Guide bolt 
             
             
                83 
               Spiral-coiled spring 
             
             
                84 
               Support disc 
             
             
                86 
               Tab 
             
             
                88 
               Flexible tongue 
             
             
                89 
               Leaf spring 
             
             
                90 
               Recess 
             
             
                92 
               Detent lobe 
             
             
                96 
               Side part 
             
             
               120 
               Angle grinder 
             
             
               122 
               Motor housing 
             
             
               123 
               Collect 
             
             
               125 
               Neck 
             
             
               133 
               Guard device 
             
             
               138 
               Swiveling arm 
             
             
               140 
               Wheel guard 
             
             
               148 
               Knurled nut 
             
             
               150 
               Rail 
             
             
               152 
               Dust removal tube 
             
             
               156 
               Handle 
             
             
               158 
               Leg spring 
             
             
               162 
               Knurled nut 
             
             
               164 
               Pivoted cover plate 
             
             
               166 
               Window 
             
             
               167 
               Knurled nut 
             
             
               174 
               Opening