Abstract:
The invention relates to a hand-held power tool, particularly an angle grinder having a housing that has a flange neck, having a protective device that can be accommodated on the flange neck and that can be pivoted in the circumferential direction, and having at least one device for blocking at least one pivoting direction of the protective device. The invention proposes that the device for locking includes at least one stop and at least one counter-stop interacting with the stop.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a 35 USC 371 application of PCT/EP2008/062994 filed on Sep. 29, 2008. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention is based on a hand-held power tool. 
     2. Description of the Prior Art 
     DE 103 43 060 A1 has already disclosed a hand-held power tool that is embodied in the form of an angle grinder. The angle grinder has a housing with an output shaft extending out from the housing and a flange that is situated on the housing and forms a flange neck. A protective device is accommodated on the flange neck and can be rotated in the circumference direction. In order to lock the protective device to prevent it from rotating in its rotation directions, a detent lever is provided, which in its neutral position, produces a form-locked engagement with the protective device. 
     ADVANTAGES AND SUMMARY OF THE INVENTION 
     The invention is based on a hand-held power tool, in particular an angle grinder, having a housing equipped with a flange neck, having a protective device that can be accommodated on the flange neck and can be rotated in the circumference direction, and having at least one locking device for preventing the protective device from rotating in at least one rotation direction. 
     According to one proposal, the locking device includes at least one stop and at least one counterpart stop that cooperates with the stop. The protective device should protect the user of the hand-held power tool from injury in the event of a possible bursting of the grinding wheel, a so-called “burst-wheel incident”. Usually, a broken grinding wheel sets the protective device into rotation. In an emergency situation or burst-wheel incident, the device according to the invention makes it possible to prevent the protective device from rotating or to stop it at a defined position in an energy-reducing fashion. The stops represent the last possible and desired rotation position of the protective device. The embodiment of the hand-held power tool according to the invention permits the manufacture of a simple and inexpensive locking device. An additional, separate locking device is not required since the components necessary for locking the protective device are to be provided on parts of the hand-held power tool. 
     The stops are advantageously embodied in such a way that in emergency operation, the protective device is only permitted to rotate in at least one rotation direction until it reaches a predetermined rotation position. In emergency operation, the device initially permits the protective device to rotate in relation to the housing until the stop and the counterpart stop come into contact with each other. In this context, “normal operation” should be understood to be an operation of the hand-held power tool in which energy from parts coming into contact with the protective device acts on the protective device only up to a predetermined value. “Emergency operation” should be understood to be an operation of the hand-held power tool in which energy from parts coming into contact with the protective device acts on the protective device above the predetermined value. The protective device is preferably situated around a disk-shaped, rotating tool of a hand-held power tool such as an angle grinder so that during operation of the hand-held power tool, the protective device can advantageously decelerate sparks and/or material particles and/or fragments of a disk such as a grinding wheel, a cut-off wheel, etc. that has burst during operation—in particular such fragments that are rotating and/or are hurled outward with powerful kinetic force—or can reduce an energy, in particular a kinetic energy, of the particles. The locking device for preventing the protective device from rotating in at least one rotation direction is embodied so that the protective device absorbs energy when struck by tool fragments by initially executing a rotating motion or turning motion in relation to the housing of the hand-held power tool. The locking device produces a frictional engagement between the flange neck and the protective device by means of a press fit. The protective device is advantageously embodied so that when a burst of energy with a predeterminable value is introduced into the protective device, the protective device rotates in relation to the housing. As a result, during normal operation, i.e. with the occurrence of a burst of energy below the predetermined value, the protective device is rigidly coupled to the flange neck and housing and only executes a rotating motion in relation to the flange neck and housing in emergency operation, i.e. with the occurrence of a burst of energy above the predeterminable value. After the introduction of a burst of energy when the tool bursts, the static friction between the flange neck and the protective device is overcome and the two components can advantageously execute a relative motion in relation to each other over a particular angular range. As a result, a particular portion of the energy is absorbed and the speed of the fragments emerging from the protective device is reduced. 
     According to another proposal, the stops are embodied so that they prevent the protective device from rotating in one rotation direction and permit the protective device to rotate in the opposite rotation direction. As a result, only the rotation direction in which the protective device would rotate uncontrollably in emergency operation is advantageously prevented. The protective device is able to rotate or to click past the detent positions in the opposite direction. 
     According to another proposal, the stop is affixed to the protective device and the counterpart stop is affixed to the housing of the hand-held power tool. When the protective device is moved in relation to the rest of the hand-held power tool, the stop affixed to the protective device moves together with the protective device while the stop affixed to the housing remains stationary in relation to the hand-held power tool. In the text below, the stop affixed to the housing is also referred to as the “static” stop and the stop affixed to the protective device is also referred to as the “mobile” stop. These stops should advantageously halt the relative movement of the protective device in relation to the housing; the stops can be used as a so-called “burst-wheel safety device”. The stops permit a relative movement of the protective device in relation to the housing of the hand-held power tool until the “static” stop on the housing and the “mobile” counterpart stop on the protective device come into contact with each other. A tool manufacturer thus has the possibility of placing the burst-wheel stops in a suitable position that is also safe for the user. This position can enable the greatest possible permissible rotation angle of the protective device while also preventing the user from being injured if the disk bursts. If a user himself is able to select the position of the burst-wheel stops, then the tool manufacturer can provide a coding of the permissible positions. 
     According to another proposal, the stop is provided on a clamping band of the protective device. This permits a simple, inexpensive manufacture that provides easy access to the stop. The arrangement of the stop on the clamping band of the protective device achieves an optimum cooperation with a counterpart stop situated on the housing. It is advantageously possible to achieve additional savings in terms of parts, space, assembly complexity, and costs if the stop is at least partially composed of a fastening element such as a clamping screw, a nut, a clamping lever, and/or other fastening elements deemed suitable by the person skilled in the art. 
     According to another proposal, the counterpart stop is provided on a transmission flange, on the flange neck, on a transmission housing, and/or on a housing element. It is thus advantageously possible for elements that are already present, such as screws for fastening the transmission flange to the transmission housing, to be additionally embodied as the counterpart stop and to be simultaneously used for this purpose. It is also conceivable for the counterpart stop to be integral to the transmission flange, the flange neck, the transmission housing, and/or the housing element. In addition, the device for locking, in particular for locking the counterpart stop of the protective device, is advantageously provided to be subsequently integrated into the transmission flange, the flange neck, the transmission housing, and/or the housing element of the hand-held power tool. 
     According to another proposal, the housing element is embodied as an element provided on or under the transmission flange or as an element that can be accommodated on the flange neck. This advantageously permits the housing stop to be placed in any conceivable position. 
     Advantageously, the stop is adjustably situated on the protective device and/or the counterpart stop is adjustably situated on the housing and/or the housing element. This makes it possible to place the burst-wheel stops in a suitable position that is also safe for the user. This position can enable the greatest possible permissible rotation angle of the protective device while preventing the user from being injured if the disk bursts. If a user himself is able to select the position of the burst-wheel stops, then the tool manufacturer can provide a coding of the permissible positions, for example by means of predetermined threaded holes for a screw-mountable stop bolt. 
     According to another proposal, the housing element is connected to the housing in an adjustable fashion. Advantageously, by means of the adjustable housing element on the housing, the counterpart stop is automatically also embodied as adjustable. The variation of the stop position can be controlled by selecting the position of the housing element on the housing, with no additional effort. According to another proposal, the housing element is connected to the housing by means of projections of the housing element and/or housing, which can be inserted into recesses of the housing and/or housing element. After the protective device is placed onto the flange neck and fastened to it, the housing element is affixed to the transmission flange. Integrating the fastening into the existing components makes it unnecessary to provide additional fastening elements, thus yielding a more reasonably priced manufacture of the hand-held power tool. It is also advantageously conceivable for this housing element to be embodied in the form of a retrofitting component. 
     According to another proposal, the locking device has at least one damping device. Usually, after the introduction of a burst of energy when the tool bursts, the static friction between the flange neck and the protective device is overcome and the two components can advantageously execute a relative motion in relation to each other over a particular angular range until the stops come into contact with each other. This absorbs a particular portion of the energy and reduces the speed of the fragments emerging from the protective device. The action of the damping device is now advantageously even more energy-absorbing. 
     According to another proposal, the counterpart stop and/or stop is equipped with the damping device and/or embodied as the damping device. As a result, through a suitable selection of the position and/or material and/or embodiment of the stop, an optimal damping action and thus energy absorption can be achieved. If a base body with a replaceable damping device is provided as the stop, then both the manufacturer and the customer can adapt the damping device to the intended use at any time. 
     According to another proposal, the stop is embodied in the form of at least one lug that engages in a groove embodied in the form of a counterpart stop. This embodiment permits a simple, inexpensive manufacture of the locking device since it requires nothing more than providing a groove and a lug in a component of the hand-held power tool. 
     According to another proposal, the delimitation of the groove is embodied in the form of an element inserted into the groove, a tab provided on the disk element, or a protuberance provided on the plate element. These embodiments make it possible to produce both a fixed and an adjustable counterpart stop on the housing. 
     According to another proposal, the counterpart stop affixed to the housing additionally serves as a hold-down element for the protective device. In this case, one component advantageously performs two functions. 
     According to the proposal in an advantageous modification of the invention, the locking device has at least one receiving element, which is situated on a transmission flange and is provided to accommodate the counterpart stop, making it possible to achieve a particularly advantageous, especially stable arrangement or accommodation of the counterpart stop on the transmission flange. The receiving element in this case is preferably designed to absorb forces—which are transmitted via the counterpart stop from a protective device that is moving in a rotation direction because a tool fragment of a bursting tool has struck the protective device—or more precisely stated, to support the counterpart stop in opposition to these forces in order to protect a user of the hand-held power tool. 
     According to another proposal, the receiving element has at least one recess on the transmission flange, which is provided to accommodate the counterpart stop, thus making it possible to implement a simply designed accommodation of the counterpart stop on the transmission flange. In a preferred embodiment, the recess is shaped to precisely fit against a shape of the counterpart stop, making it possible to achieve a particularly secure, play-free arrangement of the counterpart stop. 
     According to another proposal, the receiving element has at least one support element that supports the counterpart stop in at least one turning direction. A stable support of the counterpart stop, particularly in one turning direction of a tool, can be achieved when the stop comes into contact with the counterpart stop, thus at least partially preventing a damage to the counterpart stop. This can be achieved in a simply designed fashion if the support element is composed of a rib extending in the radial direction. 
     According to another proposal, the receiving element has at least one support element that supports the counterpart stop in at least one radial direction, thus making it possible to achieve an advantageous support of the counterpart stop toward the outside in the event of a bursting tool and additionally making it possible to absorb centrifugal forces, which occur in the radially outward direction in the event of an impact, in order to protect a user. 
     It is also possible to achieve additional savings in terms of parts, space, assembly complexity, and costs and it is also possible to achieve a particularly stable arrangement of the support element for supporting the counterpart stop in the radial direction and/or of the support element for supporting the counterpart stop in at least one rotation direction on the transmission flange if the support element for supporting the counterpart stop in the radial direction and/or the support element for supporting the counterpart stop in at least one rotation direction is/are embodied as integral to the transmission flange. In this context, “integral to” should in particular be understood to be of one piece with, manufactured from one cast, and/or embodied as one component. 
     An advantageous replacement of the counterpart stop on the transmission flange can be achieved if the counterpart stop is screw-mountably situated on a transmission flange. If a screw is provided for fastening the counterpart stop to the transmission flange preferably at the same time as the transmission flange is fastened to the hand-held power tool or more precisely stated, to its housing, then it is also possible to achieve a particularly compact arrangement and an especially stable fastening to the transmission flange. Essentially, it is also always conceivable for the counterpart stop to be already preinstalled on the transmission flange and to be installed as a unit together with the transmission flange and/or to be arranged on the transmission flange by means of an alternative fastener deemed suitable by the person skilled in the art and/or in a particularly advantageous fashion, to be embodied as integral to the transmission flange. 
     According to another proposal, the counterpart stop is composed of a material that is different from a material of a transmission flange, permitting properties of the counterpart stop to be advantageously adapted to an energy transmission or a force transmission to the counterpart stop when it is struck by the stop in the event of a bursting tool. The counterpart stop in this case can be composed of a material that already absorbs part of the energy transmitted to the counterpart stop and only transmits part of the energy to the transmission flange and/or the hand-held power tool. 
     According to another proposal, the counterpart stop has an indentation that is situated in an impact region for the stop, thus making it advantageously possible for a fastening element, in particular a nut, which is provided to be screw-mounted by means of a clamping screw, to be accommodated in the impact region and also making it possible to advantageously guide a clamping screw end past the counterpart stop. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other advantages ensue from the following description in conjunction with the drawings, in which: 
         FIG. 1  is an exploded representation of a partially depicted hand-held power tool equipped with a protective device that can be rotated in the circumference direction, 
         FIG. 2  shows a first embodiment of a device according to the invention for locking at least one rotation direction of the protective device, in which the device is equipped with a stop and a counterpart stop, 
         FIG. 3  shows a second embodiment of a locking device in which a fastening screw serves as a counterpart stop, 
         FIG. 4  shows a third embodiment of a locking device in which the counterpart stop affixed to the housing additionally serves as a hold-down element for the protective device, 
         FIG. 5  shows a fourth embodiment of a locking device in which the counterpart stop is provided on a housing element embodied in the form of a plate element, 
         FIG. 6  shows a fifth embodiment of a locking device in which the counterpart stop is provided as a catch hook on a housing element embodied in the form of a shaped sheet metal part, 
         FIG. 7  shows a sixth embodiment of a locking device in which a housing element is attached to a housing of the hand-held power tool in an adjustable fashion, 
         FIG. 8  shows a seventh embodiment of a locking device in which an insert piece equipped with a counterpart stop has projections that can be inserted into recesses in the transmission flange, 
         FIG. 9  shows an eighth embodiment of a locking device in which an insert piece equipped with a counterpart stop is situated under the transmission flange, 
         FIG. 10  shows a ninth embodiment of a locking device in which a damping device is provided, 
         FIG. 11  shows an alternative embodiment of the damping device according to  FIG. 9 , 
         FIG. 12  shows another alternative embodiment of the damping device according to  FIG. 9 , 
         FIG. 13  shows a tenth embodiment of a locking device in which a stop situated on the clamping band is embodied in the form of a damping device, 
         FIG. 14  shows an eleventh embodiment of a locking device in which a ring element equipped with a counterpart stop can be slid onto the flange neck, 
         FIG. 15  shows a twelfth embodiment of a locking device in which a counterpart stop is provided on an end surface of the flange neck, 
         FIG. 16  shows an alternative embodiment of the counterpart stop according to  FIG. 14 , 
         FIG. 17  shows another alternative embodiment of the counterpart stop according to  FIG. 14 , 
         FIG. 18  shows a thirteenth embodiment of a locking device in which the counterpart stop is supported on the end surface of the flange neck in a spring-loaded fashion in a direction of a longitudinal axis, 
         FIG. 19  shows a fourteenth embodiment of a locking device in which a lug embodied in the form of the stop engages in a groove embodied in the form of the counterpart stop and the groove has delimitations in the circumference direction, 
         FIG. 20  shows a variant of a delimitation according to  FIG. 18 , 
         FIG. 21  shows another variant of a delimitation according to  FIG. 18 , 
         FIG. 22  shows a fifteenth embodiment of a locking device in which a groove extends in an edge region of the flange neck, 
         FIG. 23  shows a sixteenth embodiment of a locking device in which the groove is formed by the flange neck and a disk element that is placed onto the flange neck, 
         FIG. 24  shows a seventeenth embodiment of a locking device in which the groove extends in the transmission flange, 
         FIG. 25  shows an eighteenth embodiment of a locking device in which the groove is formed by the flange neck and a plate element that is slid onto the flange neck and fastened to the transmission flange, 
         FIG. 26  shows a nineteenth embodiment of a locking device in which the stop is situated on the transmission housing, 
         FIGS. 27   a  and  27   b  show a first perspective depiction ( FIG. 27   a ) and a second perspective depiction ( FIG. 27   b ) of a twentieth embodiment of a locking device in which a counterpart stop is situated on the transmission flange, 
         FIGS. 28   a  and  28   b  show a first perspective depiction ( FIG. 28   a ) and a second perspective depiction ( FIG. 28   b ) of the counterpart stop from  FIGS. 27   a  and  27   b,    
         FIGS. 29   a  and  29   b  show a first perspective depiction ( FIG. 29   a ) and a second perspective depiction ( FIG. 29   b ) of a subregion of the transmission flange from  FIGS. 27   a  and  27   b , and 
         FIGS. 30   a  and  30   b  show the locking device from  FIGS. 27   a  and  27   b , with a mounted protective device. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  shows a partially depicted hand-held power tool. In the exemplary embodiments here, the hand-held power tool is an angle grinder  10 . The angle grinder  10  has a housing  14  that includes a motor housing  50  and a transmission housing  32  flange-mounted to the motor housing  50 . Protruding from the transmission housing  32  is an output shaft  52  whose free end supports a disk-shaped tool  54 , for example a grinding disk, that can be driven in rotary fashion around an axis  56  of the output shaft  52 . 
     The output shaft  52  is supported in rotary fashion in a bearing, which is not shown here and in the exemplary embodiments here, is accommodated in a transmission flange  30  constituted by the transmission housing  32 . The transmission housing  32  includes a freely extending, cylindrical flange neck  12  that adjoins the transmission flange  30  and encompasses the output shaft  52 . On its outer circumference, the flange neck  12  accommodates a protective device  16 , embodied in the form of a wheel guard, which is able to rotate in the circumference direction  18 ,  20  on the flange neck  12 . The protective device  16  includes a base body  58  and a receiving collar  28  that is connected to the base body  58  and forms a central opening to permit the output shaft  52  to pass through unimpeded. The receiving collar  28  is embodied in the form of a cylindrical body that extends parallel to the flange neck  12 . The base body  58  is provided to protect a user of the hand-held power tool from sparks and/or material particles produced during operation of the hand-held power tool. To this end, the base body  58  is composed of a disk-shaped element  60  that is semicircular in shape; the disk-shaped element  60  covers an angular range of approx. 180° of the tool  54 . As a result, a user of the hand-held power tool  10  equipped with the protective device  16  is protected in a particularly advantageous way from sparks, material particles, and/or fragments of a burst tool that are moving radially outward with high energy in that sparks and/or any material particles are conveyed toward the front, away from the user. The disk-shaped element  60  is adjoined by a protective edge  62  that initially extends perpendicular to the disk-shaped element  60  and then extends parallel to the disk-shaped element  60 . 
     The protective device  16  in the following exemplary embodiments is fastened to the flange neck  12  by means of frictional engagement through a clamping of the receiving collar  28 , which is embodied in the form of a clamping band, in a fashion similar to a pipe clamp; it is also conceivable to fasten the protective device  16  to the flange neck  12  in any other way deemed suitable by a person skilled in the art. For example, the clamping band can also be embodied in the form of a separate part that is placed around the receiving collar of the protective device  16 . The clamping band  28  is clamped in the conventional way either by means of a clamping screw  64  or by means of a clamping lever. For this purpose, the hand-held power tool  10  includes the clamping band  28  and a clamping device  66 . The clamping band  28  is embodied in an annular form and is preferably welded onto the base body  58 . Essentially, it is also conceivable for the clamping band  28  and the base body  58  to be connected to each other by means of any other connection deemed suitable by the person skilled in the art. The annular clamping band  28  is clamped around the flange neck  12  with the aid of the clamping device  66 ; the clamping device  66  accomplishes this by constricting or expanding a circumference of the annular clamping band  28 . In the clamping device  66  shown in the exemplary embodiment, two ends  68  of the clamping band  28  are clamped against each other by the clamping screw  64 . 
     In emergency operation, for example in the event of a bursting of the tool  54 , a so called burst-wheel incident, the fragments produced are hurled with high kinetic energy toward the annular inner region of the protective device  16 . The kinetic energy of the impact generates a force acting in a tangential direction, which tends to cause the protective device  16 —despite the its being clamped to the flange neck  12 —to rotate out of its position in the radial direction, i.e. in the circumference direction  18 ,  20 . The rotation of the protective device  16  in relation to the flange neck  12  and housing  14  by an angular amount that can be experimentally determined in advance absorbs a part of the kinetic energy of the fragments. The fragments of the burst disk-shaped tool  54  are decelerated and exit from an open region of the protective device  16  at a reduced speed. 
     In order to prevent the protective device  16  from rotating in the event of a burst-wheel incident or in order to stop it at a definite position in an energy-reducing fashion, the hand-held power tool  10  has a locking device  22  for preventing the protective device  16  from rotating in at least one rotation direction  18 ,  20 . According to  FIGS. 2 through 30   b , the device  22  according to the invention includes at least one stop  24  and at least one counterpart stop  26  that cooperates with the stop  24 ; the stop  24  is affixed to the protective device and the counterpart stop  26  is affixed to the housing of the hand-held power tool  10 . The rotation of the protective device  16  is to be stopped by means of the stop  24  affixed to the protective device, which strikes against the counterpart stop  26  affixed to the housing. 
     The at least one stop  24  and the at least one counterpart stop  26  according to  FIGS. 2 through 30   b  are advantageously embodied so that in emergency operation of the hand-held power tool  10 , a rotation of the protective device  16  in at least one rotation direction  18 ,  20  is enabled only until a predetermined rotation position is reached. 
     Preferably, the stops  24 ,  26  are embodied so that they prevent the protective device  16  from rotating in one rotation direction  18  or  20  and permit the protective device  16  to rotate in the opposite rotation direction  20  or  18 . 
     In the exemplary embodiments shown here, the stop  24  is provided on the clamping band  28  of the protective device  16 ; it is also possible for the stop  24  affixed to the protective device to be arranged in any other way deemed suitable by a person skilled in the art. In this regard, the exemplary embodiments show different variants of the arrangement of the stop  24  on the clamping band  28 , such as: an arrangement on an outside  72  of the clamping band  28 , an arrangement on an inside  42  of the clamping band  28 , an arrangement on an end surface  44  of the clamping band  28 , or another variant in which the stop  24  is embodied as integral to or of one piece with the protective device  16  in that the two ends  68  of the clamping band  28  serve as stops  24 . There are still other conceivable arrangements of the stop  24  on the clamping band  28  that may be deemed suitable by the person skilled in the art. The stop  24  can be embodied either as a separate part fastened to the clamping band  28  or as integral to the protective device  16 . 
     The counterpart stop  26  affixed to the housing is fastened to different parts in the exemplary embodiments shown here according to  FIGS. 2 through 30   b . For example, the counterpart stop  26  is provided on the transmission flange  30 , on the flange neck  12 , on the transmission housing  32 , and/or on a separate housing element  34  that is affixed to the housing of the hand-held power tool  10 . The counterpart stop  26  can be embodied either as a separate element fastened to the respective part  12 ,  30 ,  32 ,  34  or as integral to the respective part  12 ,  30 ,  32 ,  34 . 
     In the exemplary embodiments, the separate housing element  34  affixed to the housing is embodied as a plate element  34  provided on or under the transmission flange  30  or as a ring element that can be accommodated on the flange neck  12 . 
     Advantageously, the stop  24  can be adjustably situated on the protective device  16  and/or the counterpart stop  26  can be adjustably situated on the housing  14  and/or the housing element  34 . In addition, the housing element  34  can be adjustably connected to the housing  14 . The housing element  34  can be connected to the housing  14  by means of projections  36  that are provided on the housing element  34  and/or housing  14  and can be inserted into recesses  38  of the housing  14  and/or housing element  34 . 
     The twenty exemplary embodiments of the locking device  22  according to the invention, which are shown in perspective, disassembled depictions in  FIGS. 2 through 30   b , are described in detail below: 
       FIG. 2  shows a first embodiment of a locking device  22   a  for preventing the protective device  16   a  from rotating in at least one rotation direction  18   a ,  20   a . In this instance, a counterpart stop  26   a  is provided on the transmission flange  30   a . The counterpart stop  26   a  is integral to the transmission flange  30   a ; the transmission flange  30   a  is preferably manufactured using a casting technique. The corresponding stop  24   a  on the protective device  16   a  constitutes the “burst-wheel stop” when the two stops strike against each other. In the present exemplary embodiment, an end  68   a  of the clamping band  28   a  is provided as a stop  24   a . In this variant and in all of the others, the stop  24   a  does not absolutely have to be positioned at an end  68   a  of the clamping band  28   a ; it is instead also possible to select another suitable position. 
       FIG. 3  shows a second embodiment of a locking device  22   b . Usually, the transmission flange  30   b  is fastened to the transmission housing  32   b  by means of screws  76   b . In the second exemplary embodiment, at least one of these screws  76   b  is used as a counterpart stop  26   b ; this counterpart stop  26   b  is embodied as “static” in relation to the “rotating” protective device  16   b . As a result, one transmission flange fastening screw  76   b  is embodied in the form of an elongated, stationery bolt serving as a rotation end stop  26   b  that obstructs the ability of the protective device  16   b  to rotate. In the event of a burst-wheel incident, the counterpart stop  26   b  collides with the stop  24   b  situated on the protective device  16   b.    
       FIG. 4  shows a third embodiment of a locking device  22   c . In this instance, a counterpart stop  26   c  in the form of a hook is provided on the transmission flange  30   c , which is only partially depicted here, and cooperates with a stop  24   c  on the clamping band  28   c  of the protective device  16   c ; the stop  24   c  is composed of the two ends  68   c  of the clamping band  28   c . In addition, at an end surface  44   c  oriented toward the transmission flange  30   c , the clamping band  28   c  has a flanged edge or more precisely stated, an edge  78   c  that extends perpendicular to the clamping band  28   c  over at least part of the circumference of the clamping band  28   c  and is hooked by the counterpart stop  26   c  embodied in the form of a hook. By means of this, the counterpart stop  26   c  affixed to the housing additionally serves as a hold-down element for the protective device  16   c  by holding the protective device  16   c  in the axial operating position by means of a form-locked connection. 
       FIG. 5  shows part of a fourth embodiment of a locking device  22   d . In this a variant, a housing element  34   d  embodied in the form of an annular plate element is screw-mounted to the transmission flange  30   d ; it would also be conceivable to use any other suitable type of fastener. In this plate element  34   d , a plurality of threaded holes  80   d  situated concentric to an axis  56   d  of the output shaft are provided, in which a counterpart stop  26   d  embodied in the form of a threaded bolt can be mounted; the counterpart stop  26   d  can also be fastened to the housing element  34   d  in a different way. The different threaded holes positions permit the user to select a suitable burst-wheel stop position. It is thus possible, in the event of a burst-wheel incident, for the counterpart stop—which is affixed to the protective device and is not shown here—to be stopped at positions that are desired by the manufacturer or user. Alternatively to the annular plate element  34   d , the housing element can also be embodied in the form of an annular segment  34   e  according to  FIG. 6 . 
       FIG. 6  shows part of a fifth embodiment of a locking device  22   e . In this variant, a catch hook  26   e  is punched out from the annular segment  34   e  embodied in the form of a shaped sheet metal part. After it is bent into position, this catch functions as a counterpart stop  26   e  for the protective device. The variation of the position of the counterpart stop  26   e  can be controlled through the selection of the screw-mounting position of the annular segment  34   e . For this purpose, a plurality of threaded holes  80   e  are provided in the annular segment  34   e , situated concentric to an axis of the output shaft. Alternative to this, in lieu of the annular segment  34   e , it is also possible for an annular plate element with a catch hook to be provided. 
       FIG. 7  shows part of a sixth embodiment of a locking device  22   f . In this variant, a counterpart stop  26   f  is provided, which is permanently affixed to the annular plate element  34   f . The annular plate element  34   f  has a plurality of screw holes  80   f  situated around the circumference. By means of these screw holes  80   f , the housing element  34   f  can be adjustably fastened to the housing  14   f  or transmission flange  30   f . It is thus possible to influence the position of the counterpart stop  26   f  affixed to the housing. In this connection, it is also possible to embody another variation, not shown here, of the screw holes by embodying them as oblong holes, thus making it possible to carry out an adjustment by simply loosening the screws. 
       FIG. 8  shows part of a seventh embodiment of a locking device  22   g . In this variant, a housing element  34   g  embodied in the form of an annular insert piece is placed onto the transmission flange  30   g . This insert piece  34   g  is equipped with projections  36   g  that rest in corresponding recesses  38   g  in the transmission flange  30   g  and constrain a position-fixing of the insert piece  34   g  on the transmission flange  30   g . A depicted hook or a permanently affixed bolt of the insert piece  34   g  constitutes a counterpart stop  26   g  in relation to the rotating protective device. Both the projections  36   g  and the hook  26   g  of the insert piece  34   g  can be embodied in the form of catches. In addition, the counterpart stop  26   g  can be adjustably mounted on the insert piece  34   g.    
       FIG. 9  shows part of an eighth embodiment of a locking device  22   h . In this variant, a housing element  34   h  embodied in the form of an insert piece is situated under the transmission flange, not shown, and on the transmission housing  32   h , i.e. between the transmission flange and the transmission housing  32   h ; the insert piece  34   h  has a counterpart stop  26   h  that protrudes upward and is embodied in the form of a hook. By means of a stop, which is not shown here and is provided in the protective device, this hook  26   h  produces the impact or collision situation. 
     The locking device  22  can preferably have at least one damping device  40 ; the counterpart stop  26  and/or the stop  24  is equipped with the damping device  40  and/or embodied as the damping device  40 . 
       FIG. 10  shows part of a ninth embodiment of a locking device  22   i . In this variant, a counterpart stop  26   i  is provided, which is placed onto, preferably screw-mounted to, the transmission flange  30   i  and has a stop base body  82   i  that is open at an end surface and has a recess  84   i  for accommodating the damping device  40   i . The base body  82   i  of the counterpart stop  26   i  is equipped with the damping device  40   i , e.g. a rubber pad  40   i ′ or coil spring  40   i ″, to be integrated into the recess  84   i . The manufacturer or customer can insert different “dampers” as needed into the recess  84   i  of the stop base body  82   i . In a burst-wheel movement, the counterpart stop of the protective device, not shown here, strikes against the inserted damping device  40   i  and is decelerated by it in an energy-absorbing fashion.  FIGS. 11 and 12  show two other alternatives of the counterpart stop  26   i ,  26   i ″. In  FIG. 11 , the counterpart stop  26   i  itself is embodied as a damping device  40   i  in that the preferably integral counterpart stop  26   i ′ is embodied as plastically or elastically deformable; a potential deformation in this case can occur in a permanent or impermanent fashion. A permanent deformation would basically have the advantage that the tool manufacturer would be able to detect a burst-wheel incident. In  FIG. 12 , the counterpart stop  26   i ″ itself is likewise embodied as a damping device  40   i ″, and in fact, as a plastically deformable sheet metal element. 
       FIG. 13  shows part of a tenth embodiment of a locking device  22   j . In this variant, a stop  24   j  is provided, which is formed onto the clamping band  28   j  and consequently integrated into the protective device  16   j  and is embodied in the form of a damping device  40   j . It would also be conceivable to provide a non-integral and therefore mounted stop with a damping device. The stop  24   j  constituting the damping device  40   j  is a folded element that reduces the kinetic energy in a burst-wheel incident through the permanent or resilient deformation of the folded element. Here, too, it should be noted that a permanent deformation has the advantage of making it possible to detect a burst-wheel incident. 
       FIGS. 14 through 17  show locking devices  22  in which the counterpart stop  26  is provided on the flange neck  12 . 
       FIG. 14  shows part of an eleventh embodiment of a locking device  22   k . In this variant, the counterpart stop  26   k  affixed to the housing is provided on a housing element  34   k  that is attached to the flange neck  12   k . The housing element  34   k  is embodied in the form of a ring element that can be accommodated on the flange neck  12   k . The ring element  34   k , which is slid onto the flange neck  12 , is provided with a counterpart stop  26   k  embodied in the form of a hook, which is secured in form-locked fashion in a recess  86   k  of the transmission flange  30   k . It would also be conceivable, however, to provide a denticulation to achieve the fixing between the transmission flange and the ring element. In a burst-wheel incident, the stop of the protective device, not shown here, strikes against the stop hook  26   k.    
       FIG. 15  shows a twelfth embodiment of a locking device  22   l . In this variant, the counterpart stop  26   l  is provided on an end surface  88   l  of the flange neck  12   l . In the present exemplary embodiment, the counterpart stop  26   l  is preferably provided in a way that allows it to be adjusted by means of a plurality of threaded holes  90   l ; naturally, it would also be conceivable to provide a fixed placement of the counterpart stop. The stop  24   l  cooperating with the counterpart stop  26   l  is provided on an inside  42   l  of the clamping band  28   l , preferably in the form of a punched-out and reshaped hook. The stop according to  FIG. 16  can naturally also be provided as a separate part  24   l ′ on the clamping band  281 ′. The advantages of this variant, for example, would be a more solid design of the stop or production-related advantages. By means of a permanent deformation after a burst-wheel incident, the stop could be used as a mechanical “indicator”. This indicating function could be used to verify the occurrence of the burst-wheel incident.  FIG. 17  shows an alternative counterpart stop  26   l ′, which is situated on the end surface  88   l ′ of the flange neck  12   l ′ and is integrated into the flange neck  12   l′.    
     Stops could be embodied so that they prevent the protective device  16  from rotating in one rotation direction  18  or  20 , while permitting the protective device  16  to click past the detent positions in the opposite direction  20  or  18 .  FIG. 18  shows a partially depicted thirteenth embodiment of a locking device  22   m . In this variant, the stop  24   m  is supported on the end surface  88   m  of the flange neck  12   m  in a spring-loaded fashion in a direction of a longitudinal axis  92   m . In addition, it has a bevel  94   m  extending in the rotation direction  18   m  or  20   m . In a burst-wheel incident, the counterpart stop  26   m  affixed to the protective device can travel in one rotation direction  18   m  or  20   m  past the spring-mounted counterpart stop  26   m  provided with the bevel  94   m  in that the counterpart stop  26   m  is slid back in the longitudinal direction  92   m , whereas in the opposite direction  20   m  or  18   m , the protective device  16   m  is abruptly stopped. 
     In the exemplary embodiments below, the stop  24  is embodied in the form of at least one lug that engages in a groove embodied as the counterpart stop  26 ; the lug  24  is provided on an inside  42  and/or on an end surface  44  of a clamping band  28  of the protective device  16  and the groove  26  is embodied in the form of a recess, which is provided in an outer circumference of the flange neck  12  and/or in the transmission flange  30  and is delimited in the circumference direction  18 ,  20 . The delimitation  48  of the groove  26  is embodied in the form of an element inserted into the groove  26 , a tab provided on the disk element  34 , or a protuberance provided on the plate element  34 . 
       FIG. 19  shows a fourteenth embodiment of a locking device  22   n . In this variant, a groove serving as a counterpart stop  26   n  is provided in the flange neck  12   n  embodied in the form of a recess  26   n  that extends on an outer circumference of the flange neck  12   n  and is delimited in the circumference direction  18   n ,  20   n . A stop  24   n  embodied in the form of a lug and situated on an inside  42   n  of the clamping band  28   n  engages in this groove  26   n . In a burst-wheel incident, this groove delimitation  48   n  causes the lug  24   n  to experience an impact situation, i.e. the protective device  16   n  is prevented from rotating.  FIGS. 20 through 21  show alternative delimitations  48   n ′,  48   n ″ of an annular groove  26   n ′ extending around the flange neck  12   n ′. In  FIG. 20 , the break in the annular groove is achieved by inserting a delimiting element  48   n ′ into a recess in the flange neck  12   n ′.  FIG. 21  shows an alternative embodiment of a delimiting element  48   n ″. In order to vary the stop position, it is also possible for a plurality of delimiting elements to be provided on the circumference of the flange neck. 
       FIG. 22  shows a fifteenth embodiment of a locking device  22   o . In this variant, the flange neck  12   o  is provided with a groove serving as a counterpart stop  26   o , which is embodied in the form of a recess  26   o  that extends along the outer circumference in an edge region of the flange neck  12   o  and is delimited in the circumference direction; the recess  22   o  is open not only to the outside, but also toward the top. A stop  24   o  embodied in the form of a projection situated on an inside  42   o  of the clamping band  28   o  engages in this groove  26   o ; in a burst-wheel incident, the discontinuous groove  26   o  constitutes a rotation stop by means of the delimitations  48   o.    
       FIG. 23  shows part of a sixteenth embodiment of a locking device  22   p . In this variant, the groove  26   p  is formed by the flange neck  12   p  and a disk element  34   p  that is placed onto the flange neck  12   p  in that the flange neck  12   p  has a lower region  96   p  with a larger diameter and an upper region  98   p  with a smaller diameter and the disk element  34   p  placed onto the flange neck  12   p  has a larger diameter than the upper region  98   p  of the flange neck  12   p . The delimitation of the groove  26   p  is embodied in the form of a tab  48   p , which is provided on the disk element  34   p  and extends toward the lower region  96   p  of the flange neck  12   p . In the present exemplary embodiment, the disk element  34   p  is connected to the flange neck  12   p  by means of two riveted bolts  100   p ; it is also conceivable to use other types of fastener. If a plurality of riveted bolt holes arranged concentric to the axis  56   p  of the output shaft is provided, then the disk element  34   p  can be slid onto the flange neck  12   p  in various positions, permitting the manufacturer to shift the stop position “forward” or “back”. 
       FIG. 24  shows a seventeenth embodiment of a locking device  22   q . In this variant, the groove serving as the counterpart stop  26   q  is embodied in the form of a recess  26   q  extending in the transmission flange  30   q  and delimited in the circumference direction  18   q ,  20   q , in which a lug  24   q  engages, which is embodied in the form of a stop and is situated on an end surface  44   q  of the clamping band  28   q  of the protective device  16   q . The groove  26   q  in the housing is then delimited at a suitable location so that in a burst-wheel incident, the lug  24   q  affixed to the protective device strikes against the delimitation  48   q  and stops the rotation. 
       FIG. 25  shows an eighteenth embodiment of a locking device  22   r . In this variant, the groove serving as a counterpart stop  26   r  is provided on a housing element  34   r  embodied in the form of a plate element  34   r  provided on the transmission flange, which is not shown here. The flange neck, not shown here, and the plate element  34   r , which is slid onto the flange neck and fastened to the transmission flange, form the groove  26   r  in that the plate element  34   r  is equipped with an opening  102  whose diameter is greater than the diameter of the flange neck. This forms the groove  26   r , which is situated between the flange neck and plate element  34   r  and is delimited in the circumference direction by a protuberance  48   r  provided on the plate element  34 . This variant is particularly well-suited for retrofitting a hand-held power tool. 
       FIG. 26  shows part of a nineteenth embodiment of a locking device  22   s . In this variant, the counterpart stop  26   s  is situated on the transmission housing  32   s . Preferably, the counterpart stop  26   s  is integrated into the transmission housing  32   s . The counterpart stop can, however, also be mounted to the transmission housing as a separate component. 
       FIGS. 27   a  and  27   b  show part of a locking device  22   t  in an embodiment that differs from the ones in  FIGS. 2 through 26 . A counterpart stop  26   t  of the locking device  22   t  is situated on a transmission flange  30   t  of a hand-held power tool. The counterpart stop  26   t  is embodied in the form of a separate component from the transmission flange  30   t  and when installed, is screw-mounted to the transmission flange  30   t . In addition, the locking device  22   t  has a receiving element  104   t  that is situated on the transmission flange  30   t  and is provided to accommodate the counterpart stop  26   t . The receiving element  104   t  has a recess  106   t  on the transmission flange  30   t  ( FIGS. 29   a  and  29   b ). The recess  106   t  and the receiving element  104   t  are situated on a base body  120   t  of the transmission flange  30   t ; the base body  120   t  extends outward in a radial direction  110   t  from a flange neck  12   t  and essentially perpendicular to both the flange neck  12   t  and an axis  56  of an output shaft  52 . The recess  106   t  is situated in an outer edge region  124   t  of the base body  120   t  in the radial direction  110   t  and extends in a rotation direction  18   t ,  20   t  along a subregion of the flange neck  12   t  (see  FIGS. 27   a ,  27   b ,  29   a , and  29   b ). The recess  106   t  is also embodied as tapering in one turning direction  126   t  of a tool embodied in the form of a grinding wheel  54 . 
     The recess  106   t  is situated in the region  128   t  of a fastening recess  130   t  for the fastening of the transmission flange  30   t  to a transmission housing  32  of the hand-held power tool so that when the counterpart stop  26   t  is fastened to the transmission flange  30   t , it is simultaneously fastened to the transmission housing  32 . For this purpose, the counterpart stop  26   t  is also equipped with an opening  132   t  ( FIGS. 28   a  and  28   b ) through which a fastening screw  134   t  reaches in an installed position and is screwed to the transmission housing  32  ( FIGS. 27   a  and  27   b ). The fastening screw  134   t  is embodied in the form of a countersunk head screw so that when the protective device  16   t  rotates together with the stop  24   t  due to the transmission of an impulse from a tool part of a burst tool that is hurled outward, the stop  24   t  can come into contact with the counterpart stop  26   t  with no hindrance ( FIGS. 30   a  and  30   b ). The receiving element  104   t  also has two support elements  108   t ,  112   t  that are provided to support the counterpart stop  26   t  in the event of a burst tool ( FIGS. 27   a ,  27   b ,  29   a , and  29   b ). One of the two support elements  108   t  is provided to support the counterpart stop  26   t  in the rotation direction  18   t  and the turning direction  126   t  of the tool and for this purpose, the recess  106   t  is situated at an end  136   t , which is tapered in the rotation direction  18   t  and the turning direction  126   t , and is embodied in the form of a rib  114   t  extending in the radial direction  110   t . The additional support element  112   t  is provided to support the counterpart stop  26   t  in a radial direction  110   t . For this purpose, the support element  112   t  is embodied in the form of a wall that extends along the rotation direction  18   t ,  20   t  and the turning direction  126   t  on an outer edge  138   t  of the base body  120   t  encompassing the recess  106   t  in the radial direction  110   t . The two support elements  108   t ,  112   t  are embodied as integral to each other and are also embodied as integral to the base body  120   t  and transmission flange  30   t  ( FIGS. 27   a ,  27   b ,  29   a , and  29   b ). The support element  112   t  for supporting the counterpart stop  26   t  in the radial direction  110   t  has a height  150   t  along the axis  56  of the output shaft  52  that is at most exactly as high as a height  152   t  of a subregion  140   t  of the flange neck  12   t  oriented toward the base body  120   t . The subregion  140   t  of the flange neck  12   t  oriented toward the base body  120   t  is delimited along the axis  56  by a groove  142   t , which extends around the flange neck  12   t  in the rotation direction  18   t ,  20   t  and is provided for guiding a coding element, not shown in detail, of the protective device; the groove  142   t  can be provided by means of a subsequent machining of the transmission flange  30   t , e.g. by means of a turning procedure. 
     The counterpart stop  26   t  has a base body  144   t , which has a tapered shape of the recess  106   t  and is situated in the recess in an installed position, and has a stop element  146   t  (see  FIGS. 27   a  through  28   b ). The stop element  146   t  is situated in a tapered region  148   t  of the base body  144   t . The stop element  146   t  also has a height  154   t  that is higher than a height  150   t  of the support element  112   t  so that the stop  24   t  can come into contact with the stop element  146   t  of the counterpart stop  26   t . The stop  24   t  is composed of a fastening element  162   t —embodied in the form of a nut—of the clamping device  66   t ; the nut is screwed together with a fastening element embodied in the form of a clamping screw  164   t  in an installed position of protective device  16   t . Because of the low height  150   t  of the support element  112   t , a clamping screw end  168   t  of the clamping screw  164   t  oriented toward the counterpart stop  26   t  can be guided past the counterpart stop  26   t  so that only the clamping device  26   t  stop  24   t  constituted by the nut comes into contact with or strikes the counterpart stop  26   t  in the event that the protective device  16   t  undesirably rotates in the turning direction  126   t  of the tool because a tool part of a burst tool has been hurled outward and collided with the protective device  16   t  (see  FIGS. 30   a  and  30   b ). When assembled with the transmission flange  30   t , the stop element  146   t  of the counterpart stop  26   t  additionally rests against the support element  112   t  in the radial direction  110   t  toward the outside and rests against the support element  108   t  in the rotation direction  18   t  and the turning direction  126   t  so that in the event that the stop  53  of the protective device  16  strikes against the counterpart stop  26   t  because of a burst tool, this counterpart stop  26   t  is supported against the transmission flange  30   t  via the receiving element  104   t  and forces that are transmitted to the counterpart stop  26   t  can be conveyed away via the transmission flange  30   t . In order to achieve an advantageous absorption of energy in the event that the stop  24  strikes against the counterpart stop  26   t  because of a burst tool, the counterpart stop  26   t  is composed of a material that differs from the material of the transmission flange  30   t , e.g. an energy-absorbing material. It is also conceivable for the counterpart stop  26   t  and the transmission flange  30   t  to be integral to each other, namely embodied in the form of a single component, and/or for the counterpart stop  26   t  and the transmission flange  30   t  to be composed or manufactured of the same material. 
     The stop element  146   t  of the counterpart stop  26   t  also has an indentation  116   t  that is situated in an impact region  118   t  of an impact between the stop  24   t  and the counterpart stop  26   t  ( FIGS. 28   a ,  28   b ,  30   a , and  30   b ). The indentation  116   t  is situated in an outer edge region  156   t  of the stop element  146   t  in the radial direction  110   t  and when the counterpart stop  26   t  is mounted to the transmission flange  30   t , extends from an end region  158   t  remote from the base body  144   t  to an end region  160   t  of the support element  112   t  remote from the base body  144   t . As a result, when the stop  24   t  and the counterpart stop  26   t  strike each other due to an undesired rotation of the protective device  16   t  because a tool part of a burst tool has been hurled outward and collided with the protective device  16   t , the clamping screw end  168   t  of the clamping screw  164   t  oriented toward the counterpart stop  26   t  is guided past the counterpart stop  26   t , in particular past the impact region  118   t  of the counterpart stop  26   t , and only the stop  24   t  constituted by the nut strikes the impact region  118   t . It is basically also conceivable for an end of a clamping band  28   t  of the protective device  16   t  to constitute the stop  24   t  and/or for it to be constituted by other components of the protective device  16   t  deemed suitable by the person skilled in the art. 
     The foregoing relates to the preferred exemplary embodiments of the invention, it being understood that other variants and embodiments thereof are possible within the spirit and scope of the invention, the latter being defined by the appended claims.