Abstract:
The invention is based on a guard device ( 33 ) for a power tool, in particular for a sanding power tool, having a protective cover ( 40 ) that is provided to at least partially encompass a disk-shaped, rotating tool, and having a dust removal tube ( 52 ), the longitudinal axis of which is located at an angle of up to 80° to the axis of rotation of the tool.  
     It is proposed that part of the dust removal tube ( 52 ) passes through the plane of a flat side of the tool.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The invention is based on a guard device for a power tool, in particular for a sanding power tool, according to the preamble of claim  1 .  
           [0002]    Guard devices for power tools, in particular for angle grinders, are known, the protective covers of which offer a certain level of protection during sanding work, but do not support sufficient dust removal despite the powerful external vacuum cleaners typically used. Additionally, the typical, radial routing of the suction tube makes handling the power tool difficult because the suction tube protrudes radially.  
         ADVANTAGES OF THE INVENTION  
         [0003]    The invention is based on a guard device for a power tool, in particular for a sanding power tool, having a protective cover that is provided to at least partially encompass a disk-shaped, rotating tool, and having a dust removal tube, the longitudinal axis of which is located at an angle of up to 80° to the axis of rotation of the tool.  
           [0004]    It is proposed that part of the dust removal tube passes through the plane of a flat side of the tool.  
           [0005]    Good handling of the power tool is obtained by means of the slanted routing of the dust removal tube, whereby, simultaneously, particularly effective dust removal is obtained by means of the design of the dust removal tube, so that, in most cases, neither an internal ventilator nor an external vacuum cleaner are needed. This is essentially achieved in that at least some of particles or sanding dust cast off by the tool are thrown directly into the interior of the dust removal tube and do not first have to find their way from the inside of the protective cover to the opening of the dust removal tube. Additionally, the part of the dust removal tube that passes through the plane of a flat side of the tool usually forms a bent surface that is a conducting surface, and directs the conveying air stream produced by the rapid rotation of the tool from inside the protective cover into the dust removal tube with only minimal energy loss.  
           [0006]    The dust removal tube located at a slant to the axis of rotation of the tool makes good dust removal possible without external vacuuming due to the defined natural motion of the dust particles, and allows good freedom of motion while working. The sanding dust is captured and removed particularly well due to the over-the-corner location of the dust removal tube immediately next to the site where the tools exits a work piece surface.  
           [0007]    A particularly advantageous redirection of the conveying air and the particles is obtained in that the tool—with its radially outermost region—passes through an opening in the dust removal tube. The periphery of the disk-shaped tool is therefore at least partially encompassed by a part of the dust removal tool. As a result, conveying air and particles on both sides of the plane of rotation of the tool are guided directly into the dust removal tool. The opening can be designed as a slot, for example, into which the periphery of the tool enters. The geometery, e.g., the bend, of the part of the dust removal tube that forms the opening can differ from the geometry of the adjacent part of the dust removal tube. For example, the dust removal tube—in the part of it that encompasses the tool—can be bent upward or downward, or it can have another form appearing favorable to one skilled in the art.  
           [0008]    Advantageously, the part of the dust removal tube that passes through the plane of the flat side of the tool is situated so that sanding dust drawn off of a work piece by the tool is set into a rotational motion in the dust removal tube. When the conveying air stream with the sanding dust meets this part of the dust removal tube, the air and sanding dust are further directed into the dust removal tube in such a fashion that they execute a cyclone-like vortex motion in the dust removal tube. The conveying air and dust stream set into rotational motion in this fashion can have sufficient kinetic energy to exit the dust removal tube on its side furthest from the tool under its own power.  
           [0009]    Due to the fact that the dust removal tube tapers toward its mouth pointing toward the tool, the natural motion of the dust particles and the blow-off effect are markedly improved by means of the air movement created by the rotating sanding disk. The conveying air stream flows rapidly in the axial direction of the dust removal tube through the constriction in the mouth of the dust removal tube and therefore leaves the inner space of the protective cover with great speed. If the air also executes a rotating motion in the dust removal tube, the air stream develops a suction effect due to the widening of the dust removal tube in the direction away from the protective cover, which said suction effect helps the air to exit the protective cover and enter the dust removal tube.  
           [0010]    In an advantageous embodiment of the invention, the guard device comprises a fastening device to fasten the protective cover to the power tool, whereby the dust removal tube is moveably supported relative to the fastening device. In this fashion, the dust removal tube can be held moveably in relation to the tool and, therefore, independent of the depth of penetration of the tool in a work piece with a constant, e.g., very small clearance. As a result, the mouth of the dust removal tool can be positioned very close to the site where the particles leave the work piece, by way of which good removal of the particles is obtained.  
           [0011]    Advantageously, the dust removal tube is fastened to the protective cover. In this fashion, it is positioned in a way that is stable and easy to produce.  
           [0012]    Particularly good sanding dust removal can be achieved when the protective cover is intended—in a state in which it lies on a flat work piece in the operating position—to encompass 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 encompassed 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 protective cover and enters the surroundings.  
           [0013]    A guard device, the protective cover of which completely encompasses the tool in the axial direction in the resting position, ensures a high level of work safety: an operator is effectively protected against injury caused by the tool. This also applies for a guard device, in the case of which the tool retracts completely into the protective cover when it exits the work piece. Additionally, such a guard device ensures good protection against the release of sanding dust or particles. The dust rotating with the tool is drawn into the protective cover along with the tool retracting into the protective cover.  
           [0014]    Advantageously, the protective cover comprises an exit region in which the tool partially exits the protective cover during operation, whereby the protective cover has a glide shoe in the exit region, and the dust removal tube is permanently interconnected with the glide shoe. The glide shoe guides the protective cover along the work piece and holds the dust removal tube at a constant distance from the work piece. In this fashion, the mouth of the dust removal tube can be positioned in such a way that it points in the direction of flight of the particles.  
           [0015]    If the glide shoe constricts the cross section of the exit region in the region of the dust removal tube, it is more difficult for air to escape out of the protective cover. Excess pressure forms inside the protective cover that presses the air containing particles or dust toward the dust removal tube.  
           [0016]    Advantageously, an air inlet opening remains in the protective cover or between the protective cover 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 inlet opening into a dust removal tube, and, therefore, constant dust removal, is made possible.  
           [0017]    When the air inlet opening is located opposite from the dust removal tube relative to the tool, an air stream directed toward the dust removal tube is obtained that facilitates entry of dust into the dust removal tube.  
           [0018]    The blow-off effect of the sanding dust is further improved by means of a damping plate located inside the protective cover, since the air whirled by the rotating sanding disk 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 from the dust removal tube and be integrally molded on the protective cover, for example.  
           [0019]    A further advantage is achieved in that the protective cover comprises a window that provides an operator with a view of the tool and, in particular, on the side of the tool closest to a work piece. A particularly easy and good control of the tool position in the work piece is therefore possible. Advantageously, the protective cover comprises an observation slit. It can be formed by means of an opening in the protective cover, for example, or by means of a slant in part of the protective cover. The observation slit directed toward the narrow side of the sanding disk ensures a more controlled handling of the angle grinder with the protective cover, mainly for exact placement of the sanding disk in mortar joints. Visual control of the tool is particularly enhanced by means of the window in combination with an observation slit. The air inlet 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 window remains essentially free from dust as a result of the air turbulence.  
         SUMMARY OF THE DRAWINGS 
     
    
    
       [0020]    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.  
         [0021]    [0021]FIG. 1 is a top view of a power tool having a guard device according to the invention, in the working position,  
         [0022]    [0022]FIG. 2 is a view of the power tool in FIG. 1 from above,  
         [0023]    [0023]FIG. 3 is a view of the power tool in FIG. 1 from the opposite side,  
         [0024]    [0024]FIG. 4 is the view according to FIG. 3 rotated by 90° around the vertical axis,  
         [0025]    [0025]FIG. 5 is the view according to FIG. 1 in the resting position,  
         [0026]    [0026]FIG. 6 is the view according to FIG. 5 from the opposite side,  
         [0027]    [0027]FIG. 7 is the side view of a further exemplary embodiment of a power tool having a guard device according to the invention, in the resting position,  
         [0028]    [0028]FIG. 8 is the view according to FIG. 7 from the opposite side,  
         [0029]    [0029]FIG. 9 is the view according to FIG. 8 rotated 90° around the longitudinal axis,  
         [0030]    [0030]FIG. 10 is the view according to FIG. 7 in the working position,  
         [0031]    [0031]FIG. 11 is a detailed view of the dust removal tube acoding to FIGS. 7 and 10,  
         [0032]    [0032]FIG. 12 is a spatial representation according to FIG. 1,  
         [0033]    [0033]FIG. 13 is a spatial view from below according to FIGS. 1 and 2,  
         [0034]    [0034]FIG. 14 is a view of the adjustable stop for limiting the depth of cut,  
         [0035]    [0035]FIG. 15 is a detailed view of the depth-of-cut stop,  
         [0036]    [0036]FIG. 16 shows a section of the pivoted cover plate,  
         [0037]    [0037]FIG. 17 is a bottom view of the angle grinder protective cover according to FIG. 1,  
         [0038]    [0038]FIG. 18 shows a side shell of the protective cover as seen from the outside,  
         [0039]    [0039]FIG. 19 shows the housing shell according to FIG. 18 as seen from the inside,  
         [0040]    [0040]FIG. 20 is a spatial representation of the anterior region of the sanding machine comprising dust removal tube extending at a slant relative to the sanding tool. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0041]    [0041]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.  
         [0042]    As viewed downward at a right angle, a gearbox housing  24  adjoins the motor housing  22 , the drive shaft  26  (FIG. 13) of which said gearbox housing extends at a right angle to the plane of the drawing and carries a tool on its exposed end. The tool is a sanding disk  28 . It rotates in the direction of rotation  29  in a clockwise direction and plunges into a work piece  30 , in which it cuts a groove  32  coming from the right.  
         [0043]    As shown on the left side, a sliding button  34  of an on-and-off switch is attached to the motor housing  22 .  
         [0044]    A guard device  33  is fastened to the angle grinder  20 . It comprises a fastening device and a protective cover  40 . The fastening device is designed as a swivelling arm  38 . The swivelling arm  38  is fastened via a well-fitting mounting opening  36  (FIG. 18) to a cylindrically designed, axial extension of the gearbox housing  24 , i.e., the neck  25 . The swivelling arm  38 , in turn, is fastened to the protective cover  40  and is capable of being swivelled upward and downward around a center of rotation  42 . The swivelling arm  38  and the protective cover  40  are reliably guided in opposition to each other by means of a guide bolt  46  seated on the protective cover  40  in a guide slot  44  of the swivelling arm  38 . As shown on the left side, the swivelling arm  38  carries a knob  48 , by way of which the angle grinder  20  with the protective cover  40  can be guided on a work piece  30 . The knob  48  is also grasped to manually adjust the depth of cut, whereby the swivelling arm  38  can be adjusted upward and downward. The protective cover  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 protective cover  40  remains perpendicular to the surface of the work piece.  
         [0045]    As shown on the bottom left, the protective cover  40  carries a dust removal tube  52  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 disk.  
         [0046]    As shown on the bottom right, the protective cover  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 disk  28  in the work piece  30  and/or the groove  32 . As shown at the top right, a handle  56  projects out of the protective cover  40  at an angle, by way of which the unit comprising angle grinder  20  and protective cover  40  can be comfortably guided along the work piece  30 .  
         [0047]    A spring mechanism is located between the swivelling arm  38  and the protective cover  40  at the center of rotation  42 . The spring mechanism comprises a preloaded leg spring  58  that tries to press the swivelling arm  38  upward. As a result, the angle grinder  20  must be moved relative to the protective cover  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 disk  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 .  
         [0048]    If the angle grinder  20  with the protective cover  40  is lifted off of the work piece  30 , the leg spring  58  pulls the protective cover  40  downward relative to the swivelling arm  38 , so that the sanding disk  28  disappears completely inside the protective cover  40 .  
         [0049]    The usual method of working with the angle grinder  20  is in the advancing direction  57 , so that the work piece  30  and the direction of rotation  29  are opposite to the direction of rotation  29  of the sanding disk  28 .  
         [0050]    The view from the top shown in FIG. 2 shows the slanted arrangement of the handle  56  on the protective cover  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 swivelling arm  38 .  
         [0051]    [0051]FIG. 3 shows the angle grinder  20  with protective cover  40  according to FIG. 1 from the opposite side, also in the working position, with the sanding disk  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).  
         [0052]    The guard device  33  comprises two units capable of being moved opposite to one another, i.e., the protective cover  40  and a pivoted cover plate  64 . The pivoted cover plate  64  is located on the opposite side of the swivelling arm  38  and is intended to cover the sanding disk  68 . The pivoted cover plate  64  is capable of being swivelled together with the protective cover  40  around the center of rotation  42 . To replace the sanding disk  28 , the pivoted cover plate  64  is swivelled toward the upper left—as viewed in this drawing—from the operating position into a tool replacement position. In this outwardly swivelled 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 disk  28  can be removed in the axial direction out of the plane of the drawing.  
         [0053]    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 inlet opening  68  through which air can pass that replaces the air blown out by the rotating sanding disk  28  to remove sanding dust. Relative to the sanding disk  28 , the air inlet 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 inlet opening  68  has a size that does not depend on the depth of penetration of the sanding disk  68  in the work piece  30 , since the rail  50 —which, together with the protective cover  40 , borders the air inlet opening  68 —always lies flat on the work piece  30  independent of the depth of penetration of the sanding disk  28  in the work piece  30 .  
         [0054]    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.  
         [0055]    [0055]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 swivelling the knob  48  vertically and/or for moving the depth-of-cut stop  62  with its push button  63 —is shown. The sanding disk  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.  
         [0056]    [0056]FIG. 5 shows the angle grinder  20  according to FIG. 1 with the protective cover  40  in the resting position, in which the sanding disk  28  has disappeared inside the protective cover  40 , because the swivelling arm  38  has been moved upward relative to the protective cover  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.  
         [0057]    [0057]FIG. 6 shows how the sanding disk  28 —located behind the rail  50 —is positioned within the contour of the protective cover  40 .  
         [0058]    In FIGS. 5 and 6, the resting position of the protective cover  40  is recognizable by the fact that the knob  48 —as viewed here—is seated against the upper stop of the guide rule  60 .  
         [0059]    [0059]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 protective cover  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 swivelling 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 protective cover  140  is a rail  150  for guidance on a work piece  30  shown in FIG. 10.  
         [0060]    [0060]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.  
         [0061]    [0061]FIGS. 7 and 8 show the angle grinder  120  with the protective cover  140  in the resting position, i.e., with the sanding disk  28  drawn into the protective cover  140 , while FIGS. 9 and 10 show the same angle grinder  120  in the working position, i.e., with the sanding disk  28  protruding below the rail  150 .  
         [0062]    [0062]FIG. 9 clearly shows a collet  123  that clamps a collar of the protective cover  140  tightly against the neck  125  of the angle grinder  120 . The protective cover  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 disk  28  was previously removed. Also shown are the knurled nut  167  for holding the pivoted cover plate  164  in position against the protective cover  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 .  
         [0063]    [0063]FIG. 9 clearly shows the leg spring  158 , with which the angle grinder  120  is automatically moved relative to the protective cover  140  around the center of rotation  142  into the resting position. Also shown is a suction tube  151  for connection to a vacuum cleaner, with which the sanding dust can be effectively removed.  
         [0064]    [0064]FIG. 10 shows the angle grinder  120  in the working position, whereby sanding dust is thrown in the direction of rotation  29  of the sanding disk  28  tangentially from the point where the sanding disk  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.  
         [0065]    [0065]FIG. 11 shows a detained view of the dust removal tube  152  in its position relative to the sanding disk  28 . One can see that the radially outermost region of the sanding disk  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 disk  28 . The opening  174  is designed in such a fashion that part of the dust removal tube  152  reaches behind the sanding disk  28 . The opening  174  is therefore designed in the shape of a slot.  
         [0066]    The conveying air stream produced by the sanding disk  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 disk  28 , as indicated by the arrows. The conveying air stream with the sanding 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 .  
         [0067]    [0067]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 protective cover  40  are particularly easy to see.  
         [0068]    [0068]FIG. 13 shows a spatial representation nearly parallel to the sanding disk  28  from the underside of the protective cover  40 . The design of the rail  50  with a glide shoe  49  is shown particularly clearly. The rail  50  is located in the exit region of the protective cover  40 , where part of the sanding disk exits the protective cover  40  during operation. The glide shoe  49  of the rail  50  constricts the cross section of the exit region of the protective cover  40 . This helps the air stream in the protective cover  40  along in the direction toward the dust removal tube  52 .  
         [0069]    As shown on the left side, a damping plate  76  is located next to the sanding disk  28 , which said damping plate extends radially very close to the periphery of the sanding disk  28  and dampens a movement of air caused by the rotating sanding disk  28  during sanding. As a result, a certain vacuum is produced inside the protective cover  40 , which said vacuum blows through the dust removal tube  52  and takes any sanding dust present along with it.  
         [0070]    The collet  23  with the clamping nut for fastening the protective cover  40  to the gearbox housing  24  is shown. On the top, the protective cover  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.  
         [0071]    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 swivelling the pivoted cover plate  64  upward into its release position to remove the sanding disk  28 . Additionally, the arrow also indicates the direction of rotation of the sanding disk  28 . The pivoted cover plate  64  is swung to the left by approximately 180° around the center of rotation  42  so that the sanding disk  28  can be exposed and replaced after the retaining nut  27  is removed.  
         [0072]    The frame segments  70  for accommodating the window  66  in the corresponding opening are also clearly shown.  
         [0073]    [0073]FIG. 14 shows the guide rule  60  as a fixed part of the protective cover  40 , relative to which the swivelling arm  38  can be adjusted via swivelling. The position of the swivelling 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.  
         [0074]    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 swivelling arm  38  with its knurled thumb screw  48   a  can only be swivelled up to said stop. With this, a reproducible depth of cut is established.  
         [0075]    [0075]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 .  
         [0076]    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 disk  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 .  
         [0077]    [0077]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.  
         [0078]    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  
         [0079]    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 protective cover  40 . By swiveling the pivoted cover plate  64  using the swivel grip  65  to the right 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 minimal force.  
         [0080]    [0080]FIG. 17 shows an underside view of the protective cover  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 disk  28  can enter and exit.  
         [0081]    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 swivelling 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 disk  28 . As a result, the conveying air stream produced by the sanding disk  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 protective cover  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 protective cover  40 , the air stream develops a suction effect due to its rotation, which said suction effect helps the air to exit the protective cover and enter the dust removal tube  52 .  
         [0082]    The protective cover  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.  
         [0083]    [0083]FIG. 18 shows a detained view of the stationary, shell-like side part  96  of the protective cover  40 , to which the welded-on guide rule  60  is attached as shown on the right.  
         [0084]    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 protective cover  40 , at the site of origination of the sanding dust when the angle grinder  20  is used, through which said suction tube any sanding dust created moves by means of the high natural speed imparted by the sanding disk  28  in conjunction with the blast air stream produced by the sanding disk  28  itself.  
         [0085]    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 protective cover  40  until the maximum depth of cut is reached.  
         [0086]    [0086]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 .  
         [0087]    [0087]FIG. 20 is a side view of the protective cover  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 protective cover  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 disk  28  passes through the opening  74  with its radially outermost region.  
       Reference numerals  
       [0088]    [0088] 20  Angle grinder  54  Observation opening  
         [0089]    [0089] 22  Motor housing  56  Handle  
         [0090]    [0090] 23  Collet  57  Advancing direction  
         [0091]    [0091] 24  Gearbox housing  58  Leg spring  
         [0092]    [0092] 25  Neck  59  Outer contour  
         [0093]    [0093] 26  Drive shaft  60  Guide rule  
         [0094]    [0094] 27  Retaining nut  61  Slot  
         [0095]    [0095] 28  Sanding disk  62  Depth-of-cut stop  
         [0096]    [0096] 29  Direction of rotation  63  Push button  
         [0097]    [0097] 30  Work piece  64  Pivoted cover plate  
         [0098]    [0098] 32  Groove  65  Swivel grip  
         [0099]    [0099] 33  Guard device  66  Window  
         [0100]    [0100] 34  Sliding button  68  Air inlet opening  
         [0101]    [0101] 36  Mounting opening  70  Frame segment  
         [0102]    [0102] 38  Swivelling arm  72  Snap-in tongue  
         [0103]    [0103] 40  Protective cover  73  Pass-through slot  
         [0104]    [0104] 42  Center of rotation  74  Opening  
         [0105]    [0105] 44  Guide slot  76  Damping plate  
         [0106]    [0106] 46  Guide bolt  78  Profile carrier  
         [0107]    [0107] 48  Knob  79  Mating profile  
         [0108]    [0108] 48   a  Knurled thumb screw  80  Tab  
         [0109]    [0109] 49  Glide shoe  82  Guide bolt  
         [0110]    [0110] 50  Rail  83  Spiral-coiled spring  
         [0111]    [0111] 52  Dust removal tube  84  Support disk  
         [0112]    [0112] 86  Tab  
         [0113]    [0113] 88  Flexible tongue  
         [0114]    [0114] 90  Recess  
         [0115]    [0115] 92  Detent lobe  
         [0116]    [0116] 96  Side part  
         [0117]    [0117] 120  Angle grinder  
         [0118]    [0118] 122  Motor housing  
         [0119]    [0119] 123  Collet  
         [0120]    [0120] 125  Neck  
         [0121]    [0121] 133  Guard device  
         [0122]    [0122] 138  Swivelling arm  
         [0123]    [0123] 140  Protective cover  
         [0124]    [0124] 142  Center of rotation  
         [0125]    [0125] 148  Knurled nut  
         [0126]    [0126] 150  Rail  
         [0127]    [0127] 152  Dust removal tube  
         [0128]    [0128] 156  Handle  
         [0129]    [0129] 158  Leg spring  
         [0130]    [0130] 162  Knurled nut  
         [0131]    [0131] 164  Pivoted cover plate  
         [0132]    [0132] 166  Window  
         [0133]    [0133] 167  Knurled nut  
         [0134]    [0134] 174  Opening