Patent Publication Number: US-2015087211-A1

Title: Machine Tool Braking Device

Description:
PRIOR ART 
     Power tool braking devices, in particular a hand-held power tool braking devices, are already known from EP 2 364 811 A2 and EP 1 938 924 A1, which comprise a braking unit, and comprise an operating unit, having a movably mounted operating element, for activating and/or deactivating the braking unit. 
     DISCLOSURE OF THE INVENTION 
     The invention is based on a power tool braking device, in particular a hand-held power tool braking device, comprising at least one braking unit, and comprising at least one operating unit, having a movably mounted operating element, for activating and/or deactivating the braking unit. 
     It is proposed that the operating element be mounted such that it can pivot about a movement axis of the operating element. Preferably, the braking unit is realized as a mechanical braking unit. Particularly preferably, the braking unit is realized as a friction brake. It is also conceivable, however, for the braking unit to be of a different design, considered appropriate by persons skilled in the art, such as, for example, designed as a magnetic brake (hysteresis brake, eddy-current brake, etc). The expression “mechanical braking unit” is intended here to define, in particular, a braking unit provided to bring at least one braking element and/or one counter-braking element of the braking unit into a braking position and/or into a release position as a result of a mechanical actuation, in particular as a result of a force of a component being exerted upon the braking element and/or the counter-braking element by a direct contact between the component and the braking element and/or the counter-braking element, in particular in isolation from a magnetic force. “Provided” is to be understood to mean, in particular, specially designed and/or specially equipped. A “braking position” is to be understood here to mean, in particular, a position of the counter-braking element and/or of the braking element in which, for the purpose of reducing a speed of a moving component in a predefined period of time, in particular by at least more than 50%, preferably at least more than 65%, and particularly preferably by at least more than 80%, at least one braking force is exerted upon the moving component, in at least one operating state. In this case, in particular, the predefined period of time is less than 5 s. The term “release position” is intended here to define, in particular, a position of the braking element and/or of the counter-braking element in which an action of the braking force upon the moving component for the purpose of reducing the speed is at least substantially prevented. The braking unit is preferably provided to brake the component, in particular, in a predefined period of time of greater than 0.1 s, preferably greater than 0.5 s, and particularly preferably less than 3 s, starting from a working speed, in particular to a speed that is less than 50% of the working speed, preferably less than 20% of the working speed, and particularly preferably to a speed of 0 m/s. 
     An “operating unit” is to be understood here to mean, in particular, a unit having at least one component, in particular the operating element, which can be actuated directly by an operator, and which is provided to influence and/or alter a process and/or a state of a unit coupled to the operating unit, through an actuation and/or through an input of parameters. Particularly preferably, the operating unit is provided, in addition to activating and/or in addition to deactivating the braking unit, to enable and/or interrupt an energy supply to a drive unit of a portable power tool provided with the power tool braking device, as a result of an actuation of the operating element. In the case of an activation of the braking unit by means of the operating unit, the braking element and/or the counter-braking element are/is preferably brought into the braking position. In the case of a deactivation of the braking unit by means of the operating unit, the braking element and/or the counter-braking element are/is preferably brought into the release position. 
     An “operating element” is to be understood to mean, in particular, an element provided to pick up an input quantity from an operator in the case of an operating action, and in particular to be contacted directly by an operator, wherein contacting of the operating element is sensed and/or an actuating force exerted upon the operating element is sensed and/or is transferred mechanically for the purpose of actuating a unit. The expression “mounted such that it can pivot” is intended here to define, in particular, a mounting of the operating element, wherein it is possible for the operating element to move, about at least one axis, by an angle greater than 1°, preferably greater than 5°, and particularly preferably less than 45°. The operating element is preferably realized as a latch element, a so-called paddle switch. A “latch element” is to be understood here to mean, in particular, an operating element that, along a direction of longitudinal extent of the operating element, has a longitudinal extent that is greater than a transverse extent of the operating element that runs at least substantially perpendicularly in relation to the direction of longitudinal extent and runs at least substantially transversely in relation to a direction of movement of the operating element. Preferably, a maximum longitudinal extent of the latch element is at least 2 times greater, preferably at least 2.5 times greater, and particularly preferably at least 3 times greater than a maximum transverse extent of the latch element. The expression “substantially perpendicularly” is intended here to define, in particular, an alignment of a direction relative to a reference direction, wherein the direction and the relative direction, in particular as viewed in one plane, enclose an angle of 90° and the angle has a maximum deviation of, in particular, less than 8°, advantageously less than 5°, and particularly advantageously less than 2°. “At least substantially transversely” is to be understood here to mean, in particular, an alignment of a plane and/or of a direction, relative to a further plane and/or a further direction, that preferably deviates from a parallel alignment of the plane and/or of the direction, relative to the further plane and/or the further direction. The latch element preferably comprises an operating face that, when the latch element is in a mounted state, extends at least over a major part of a maximum transverse extent of a handle housing of a portable power tool. Advantageously, the design of the power tool braking device according to the invention makes it possible to achieve a high degree of operating comfort. In this case, advantageously, owing to the fact that the operating element is mounted such that it can pivot, a small actuating force can be converted into a large positioning force for activating and/or deactivating the braking unit. Moreover, advantageously, owing to the fact that the operating element is mounted such that it can pivot, a biased-off function can be implemented through simple design means. In addition, advantageously, the operating element can be mounted such that it is not susceptible to dirt. 
     Furthermore, it is proposed that the movement axis of the operating element extend at least substantially transversely in relation to a rotation axis of a rotatably mounted braking element of the braking unit. Preferably, the movement axis extends at least substantially perpendicularly in relation to the rotation axis of the braking element. Preferably, the movement axis of the operating element extends at least substantially parallelwise in relation to a direction of transverse extent of the operating element. The rotation axis of the braking element is preferably coaxial with a rotation axis of a drive shaft of a drive unit, in particular of an electric motor, of a portable power tool. Particularly preferably, the braking element is fixed to the drive shaft in a rotationally fixed manner. It is also conceivable, however, for the braking element to be fixed to a fan propeller of the drive unit by means of a form-fitting and/or adhesive connection. The fan propeller may be realized as a plastic component, as a metallic component and/or as another component considered appropriate by persons skilled in the art. If the fan propeller is designed as a metallic component, it is advantageously possible to prevent a thermal overload caused by a braking force. Moreover, it is likewise conceivable for the braking element to be fixed to another component of the portable power tool such as, for example, a component of a transmission, etc. Particularly, preferably, the braking element is realized as a brake disk. The brake disk is preferably made of high-grade steel and/or of another material, considered appropriate by persons skilled in the art, such as, for example, sintered bronze, steel, nitrided steel, aluminum or another surface-treated steel and/or metal. The counter-braking element is preferably realized as a friction lining, or as a friction lining carrier having friction linings disposed thereon. Advantageously, the design according to the invention makes it possible to achieve a large lever arm for the purpose of actuating the operating element. Thus, advantageously, it is possible to achieve an operating element that can be actuated with a small application of force, such that a high degree of operating comfort can be achieved. 
     Further, in an alternative design of the power tool braking device, it is proposed that the movement axis of the operating element extend at least substantially parallelwise in relation to a rotation axis of a rotatably mounted braking element of the braking unit. Thus, particularly preferably, the movement axis of the operating element extends at least substantially parallelwise in relation to a direction of longitudinal extent of the operating element. “Substantially parallelwise” is to be understood here to mean, in particular, an alignment of a direction relative to a reference direction, in particular in one plane, the direction deviating from the reference direction by, in particular, less than 8°, advantageously less than 5°, and particularly advantageously less than 2°. Advantageously, the design of the power tool braking device according to the invention enables the pivotally mounted operating element to be operated in an ergonomic manner. 
     Moreover, it is proposed that the operating unit have at least one movement coupling element for coupling the operating element to a counter-braking element of the braking unit. The term “movement coupling element” is intended here to define, in particular, an element by which two components that are spaced apart from each other, in particular realized so as to be separate from each other, are connected to each other in a movement-dependent manner. Preferably, a force resulting from a movement of the operating element is picked off by means of the movement coupling element and transmitted to at least one component, in particular to the counter-braking element, of the braking unit for the purpose of activating and/or deactivating the braking unit. It is also conceivable, however, for the braking element or the counter-braking element to be disposed directly on the operating element, such that the braking element and/or the counter-braking element are/is brought into a release position or into a braking position as a result of a pivot movement of the operating element about the movement axis of the operating element, without further elements being interposed between the operating element and the braking element or counter-braking element. If the braking element or the counter-braking element is disposed on the operating element, it is conceivable for the braking element or the counter-braking element to be realized, for example, as a drum that surrounds the operating element, at least in a partial region, and that is connected to an armature shaft of the drive unit, and for the braking element or the counter-braking element to be realized as a brake lining that is disposed on the operating element and that, as a result of a pivot movement of the operating element, is pressed on to an inside of the drum or moved away from the latter. Moreover, it is likewise conceivable for the movement coupling element, as a result of being actuated by the operating element, to move a magnet that is provided to move the braking element and/or the counter-braking element, in order to bring the braking unit into a release position and/or into a braking position. The counter-braking element is preferably mounted such that it can pivot about a rotation axis that is coaxial with the rotation axis of the braking element. Moreover, the counter-braking element is preferably mounted such that it can move translationally along the rotation axis of the braking element. Since it is mounted in a pivoting and, in addition, translational manner, the counter-braking element can thus preferably execute a movement on which there is superposed a movement of the counter-braking element that moves rotationally and translationally. In an alternative design of the braking unit, the counter-braking element is mounted so as to be movable only translationally along a movement axis of the counter-braking element that is coaxial with the rotation axis of the braking element. Moreover, in a further, alternative design, it is conceivable for the counter-braking element to be mounted such that it can pivot about a movement axis of the counter-braking element that runs at least substantially transversely in relation to the rotation axis of the braking element. The movement coupling element may be composed of plastic, of metal, of composite material, as a hybrid component, etc. By means of the design of the power tool braking device according to the invention, a movement of the braking element resulting from an actuation of the operating element can be achieved through simple design means. 
     It is additionally proposed that the operating unit have at least one movement coupling element realized as a cable pull element, for coupling the operating element to a counter-braking element of the braking unit. A “cable pull element” is to be understood here to mean, in particular, an element that can support tensile forces acting upon the element, and that is dissociated from support of compressive forces acting upon the element. In this case, the movement coupling element can in each case be connected directly and/or indirectly to the operating element and the counter-braking element. Advantageously, it is possible to realize a power tool braking device that occupies little space. Moreover, distances between the operating element and the counter-braking element can be spanned through simple design means, wherein a simple deflection can be achieved for guiding the movement coupling element past other components. 
     In an alternative design of the power tool braking device, the operating unit has at least one movement coupling element realized as a rack element, for coupling the operating element to a counter-braking element of the braking unit. Advantageously, a robust operating unit can be realized. In addition, advantageously, one type of movement can be converted into another type of movement. 
     In a further alternative design of the power tool braking device, the operating unit has at least one movement coupling element realized as a rotary lever element, for coupling the operating element to a counter-braking element of the braking unit. Advantageously, a lever principle can be used for stepping-up and/or stepping-down actuating forces. 
     It is furthermore proposed that the operating unit comprise at least one switch-on blocking element, which is connected to a movement coupling element of the operating unit. The term “switch-on blocking element” is intended here to define, in particular, an element provided to lock and/or unlock a movement blocking device of the operating unit. A “movement blocking device” is to be understood here to mean, in particular, a blocking mechanism provided to prevent insofar as possible a movement of a movably mounted component along at least one distance and/or about at least one axis, at least in an operating state, by means of a mechanical, electrical and/or electronic blocking device. Preferably, the movement blocking device is provided to prevent insofar as possible a movement of the movably mounted operating element, at least in an operating state, by means of a mechanical blocking device. It is also conceivable, however, for the movement blocking device to prevent insofar as possible a movement of the operating element, at least in an operating state, by means of an electromagnetic action of force and/or a permanent-magnet action of force, such as, for example, by means of displaceable magnets, upon the operating element. Preferably, the movement blocking device can be unlocked by the switch-on blocking element, to enable the operating element to be moved as a result of an actuation of the operating element. The design according to the invention makes it possible, advantageously, to achieve reliable activation and/or deactivation of the braking unit as a result of an actuation of the switch-on blocking element. 
     Moreover, it is proposed that the operating unit comprise at least one switch-on blocking element, which is mounted such that it can pivot on the operating element. For the purpose of unlocking the movement blocking device, the switch-on blocking element is preferably mounted such that it can pivot, in at least two mutually differing directions, about a pivot axis of the switch-on blocking element. Preferably, the operating unit comprises at least one spring element, which applies a spring force to the switch-on blocking element in the direction of a central position, in which a movement of the operating element is prevented insofar as possible by means of the movement blocking device. Advantageously, it is possible to achieve comfortable operation of the switch-on blocking element. 
     The invention is additionally based on a power tool comprising at least one power tool braking device according to the invention. The power tool is preferably realized as a portable power tool. A “portable power tool” is to be understood here to mean, in particular, a power tool, in particular a hand-held power tool, that can be transported by an operator without the use of a transport machine. The portable power tool has, in particular, a mass of less than 50 kg, preferably less than 20 kg, and particularly preferably less than 10 kg. Particularly preferably, the portable power tool is realized as an angle grinder. It is also conceivable, however, for the portable power tool to be of another design considered appropriate by persons skilled in the art, such as, for example, designed as a hand-held planer, as a multifunction power tool, as a portable router, as a sander, and/or as an electrically operated garden appliance. Advantageously, for an operator of the portable power tool, a high degree of operating comfort can be achieved. 
     The power tool braking device according to the invention and/or the power tool according to the invention are/is not intended in this case to be limited to the application and embodiment described above. In particular, the power tool braking device according to the invention and/or the power tool according to the invention may have individual elements, components and units that differ in number from the number stated herein, in order to fulfill a principle of function described herein. 
    
    
     
       DRAWING 
       Further advantages are given by the following description of the drawing. The drawing shows exemplary embodiments of the invention. The drawing, the description and the claims contain numerous features in combination. Persons skilled in the art will also expediently consider the features individually and combine them to create appropriate further combinations. 
       In the drawing: 
         FIG. 1  shows a power tool according to the invention, having a power tool braking device according to the invention, in a schematic representation, 
         FIG. 2  shows a detail view of a braking unit, with the power tool braking device according to the invention in a braking position, in a schematic representation, 
         FIG. 3  shows the power tool according to the invention with an actuated operating element of an operating unit of the power tool braking device according to the invention, in a schematic representation, 
         FIG. 4  shows a detail view of the braking unit, with the power tool braking device according to the invention in a release position, in a schematic representation, 
         FIG. 5  shows an alternative power tool according to the invention, having a power tool braking device according to the invention, in a schematic representation, 
         FIG. 6  shows a further alternative power tool according to the invention, having a power tool braking device according to the invention, in a schematic representation, 
         FIG. 7  shows a further alternative power tool according to the invention, having a power tool braking device according to the invention, in a schematic representation, 
         FIG. 8  shows a further alternative power tool according to the invention, having a power tool braking device according to the invention, in a schematic representation, 
         FIG. 9  shows a detail view of an alternative actuating mechanism of the operating unit of the power tool braking device according to the invention, in a schematic representation, 
         FIG. 10  shows a detail view of a further alternative actuating mechanism of the operating unit of the power tool braking device according to the invention, in a schematic representation, 
         FIG. 11  shows a detail view of a further alternative actuating mechanism of the operating unit of the power tool braking device according to the invention, in a schematic representation, 
         FIG. 12  shows a detail view of a further alternative actuating mechanism of the operating unit of the power tool braking device according to the invention, in a schematic representation, 
         FIG. 13  shows a detail view of a further alternative actuating mechanism of the operating unit of the power tool braking device according to the invention, in a schematic representation, 
         FIG. 14  shows a detail view of a further alternative actuating mechanism of the operating unit of the power tool braking device according to the invention, in a schematic representation, 
         FIG. 15  shows a detail view of a further alternative actuating mechanism of the operating unit of the power tool braking device according to the invention, in a schematic representation, 
         FIG. 16  shows a detail view of a braking unit, with a further alternative power tool braking device according to the invention in a braking position, in a schematic representation, 
         FIG. 17  shows a detail view of the braking unit from  FIG. 16  in a release position, in a schematic representation, and 
         FIG. 18  shows a detail view of a braking unit, with a further alternative power tool braking device according to the invention in a braking position, in a schematic representation. 
     
    
    
     DESCRIPTION OF THE EXEMPLARY EMBODIMENTS 
       FIG. 1  shows a power tool  30   a , realized as a portable power tool, having a power tool braking device  10   a . The power tool  30   a  in this case is realized as an angle grinder. The power tool  30   a  comprises a protective hood unit  32   a  and a power tool housing  34   a , which encompasses a motor housing  36   a  and a transmission housing  38   a . The motor housing  36   a  constitutes a main handle that, starting from the transmission housing  38   a , extends in a direction away from the transmission housing  38   a . Moreover, the motor housing  36   a  is provided to accommodate and carry a drive unit  40   a  of the power tool  30   a . The drive unit  40   a  is realized as an electric motor unit. It is also conceivable, however, for the drive unit  40   a  to be of a different design, considered appropriate by persons skilled in the art, such as, for example, designed as an internal combustion drive unit, as a hybrid drive unit, etc. The transmission housing  38   a  is provided to accommodate a transmission unit  42   a . Extending out of the transmission housing  38   a  there is a spindle  44   a  of the transmission unit  42   a , to which a working tool  46   a , for performing work on a workpiece (not represented in greater detail here) can be fixed. The working tool  46   a  is realized as a sanding disk. It is also conceivable, however, for the working tool  46   a  to be realized as a parting or polishing disk. The drive unit  40   a  is provided to drive the working tool  46   a  in rotation, via the transmission unit  42   a . Via a drive element  48   a  of the drive unit  40   a  that can be driven in rotation, the transmission unit  42   a  is connected, in a manner already known to persons skilled in the art, to a transmission element  50   a  of the transmission unit  42   a  that is realized, for example, as a gear wheel such as, for example, a ring gear. 
     The power tool braking device  10   a  comprises at least one braking unit  12   a , and comprises at least one operating unit  16   a , having a movably mounted operating element  14   a , for activating and/or deactivating the braking unit  12   a . In addition to activating and/or deactivating the braking unit  12   a , the operating element  14   a  is provided to close an electric circuit for the purpose of supplying energy to the drive unit  40   a , to enable the power tool  30   a  to be put into operation. The operating element  14   a  is provided to close an electric circuit by means of an actuation of an electric switch  54   a  of the power tool  30   a . For this purpose, the operating element  14   a  has an actuating region that, as a result of a movement of the operating element  14   a , actuates a switch actuating element  56   a  of the operating unit  16   a  that is movably mounted in the motor housing  36   a . The switch actuating element  56   a  is pivotally mounted in the motor housing  36   a . It is also conceivable, however, for the actuating region of the operating element  14   a  to actuate the switch  54   a  directly. The operating element  14   a  is realized as a latch element. The operating element  14   a  in this case extends, along a direction of main extent  64   a  of the power tool  30   a , over at least 70% of a total extent of the motor housing  36   a.    
     The operating element  14   a  is mounted such that it can pivot about a movement axis  18   a  of the operating element  14   a . The movement axis  18   a  of the operating element  14   a  extends at least substantially transversely in relation to a rotation axis  20   a  of a rotatably mounted braking element  22   a  of the braking unit  12   a . A pivot bearing region  88   a  of the operating element  14   a  in this case is disposed at an end of the operating element  14   a  that faces away from the transmission housing  38   a . The braking unit  12   a  is realized as a mechanical friction brake unit. The braking element  22   a  is thus realized as a brake disk. The braking element  22   a  in this case is fixed on a drive shaft  52   a  of the drive unit  40   a  in a rotationally fixed manner by means of a force-closed connection such as, for example, a press fit. The rotation axis  20   a  of the braking element  22   a  is thus coaxial with a rotation axis of the drive shaft  52   a . Moreover, the rotation axis  20   a  of the braking element  22   a  extends at least substantially parallelwise in relation to the direction of main extent  64   a . The drive shaft  52   a  is realized as an armature shaft of the drive unit  40   a . The braking element  22   a  in this case is disposed on the drive shaft  52   a , on a side of a fan propeller  110   a  of the drive unit  40   a  that faces toward a stator of the drive unit  40   a . It is also conceivable, however, for the braking element  22   a  to be connected to the drive shaft  52   a  in a rotationally fixed manner by means of a form-closed and/or adhesive connection. Moreover, it is conceivable for the braking element  22   a  to be disposed in a rotationally fixed manner on the drive shaft  52   a , or to be disposed in a rotationally fixed manner on the spindle  44   a , at another position considered appropriate by persons skilled in the art. 
     The operating unit  16   a  additionally has at least one movement coupling element  24   a , for coupling the operating element  14   a  to a counter-braking element  26   a  of the braking unit  12   a . The movement coupling element  24   a  is mounted in a translationally movable manner in the power tool housing  34   a . Moreover, the movement coupling element  24   a  comprises a coupling region  58   a  that faces toward the operating element  14   a . The coupling region  58   a  comprises a ramp-type actuating face  60   a . The actuating face  60   a  is provided to act in combination with an inclined face  62   a  of the operating element  14   a  that is realized to correspond to the actuating face  60   a , as a result of a movement of the operating element  14   a  in the direction of the power tool housing  34   a . As a result of the combined action of the actuating face  60   a  and the inclined face  62   a , the movement coupling element  24   a , upon a movement of the operating element  14   a  in the direction of the power tool housing  34   a , is moved translationally in the direction of the transmission housing  38   a . As a result of this, the counter-braking element  26   a  of the braking unit  12   a  is moved away from the braking element  22   a . The braking unit  12   a  is thus brought into a release position ( FIG. 3 ). It is also conceivable, however, in an alternative design of the power tool braking device  10   a , for the movement coupling element  24   a  to be moved in a direction away from the transmission housing  38   a , in order to bring the braking unit  12   a  into the release position. Moreover, it is conceivable for the operating unit  16   a  to comprise a spring element, which applies a spring force to the movement coupling element  24   a , to enable the movement coupling element  24   a  to be reset to an initial position after an action of force has been removed. 
     The movement coupling element  24   a  has a movement transmission region  66   a  for the purpose of moving the counter-braking element  26   a . The movement transmission region  66   a  comprises at least one ramp-type actuating element  68   a  ( FIG. 2 ). The actuating element  68   a  is provided to act in combination with a coupling extension  70   a  of the counter-braking element  26   a . When the counter-braking element  26   a  is in a mounted state, the coupling extension  70   a  extends at least substantially perpendicularly in relation to the rotation axis  20   a  of the braking element  22   a , starting from the counter-braking element  26   a . The coupling extension  70   a  is realized so as to be integral with the counter-braking element  26   a . It is also conceivable, however, for the coupling extension  70   a  to be realized so as to be separate from the counter-braking element  26   a , and to be fastened to the counter-braking element  26   a  by means of at least one fastening element considered appropriate by persons skilled in the art, such as, for example, a rivet, a screw, etc. 
     The counter-braking element  26   a  additionally has at least two groove-type recesses  72   a ,  74   a , which extend at least substantially transversely in relation to the rotation axis  20   a  of the braking element  22   a . It is also conceivable, however, for the counter-braking element  26   a  to be fixed on an additional bearing element of the braking unit  12   a , and for the groove-type recesses  72   a ,  74   a  to be disposed in the additional bearing element. Moreover, the braking unit  12   a  comprises at least two pin-type guide elements  76   a ,  78   a , which each engage in one of the recesses  72   a ,  74   a . The groove-type recesses  72   a ,  74   a  are disposed on the counter-braking element  26   a , offset by approximately 180° relative to each other. The pin-type guide elements  76   a ,  78   a  are disposed on a brake carrier element  80   a  of the braking unit  12   a , offset by approximately 180° relative to each other. The groove-type recesses  72   a ,  74   a  and the pin-type guide elements  76   a ,  78   a  together constitute a cam mechanism of the braking unit  12   a . The counter-braking element  26   a  is mounted so as to be movable relative to the brake carrier element  80   a . The brake carrier element  80   a  is disposed in the power tool housing  34   a , solid with the housing. 
     As a result of a translational movement of the movement coupling element  24   a  that is caused by the movement of the operating element  14   a , the coupling extension  70   a  slides on a face of the actuating element  68   a  that faces toward the coupling extension  70   a . As a result of this, a combined action of the groove-type recesses  72   a ,  74   a  and the pin-type guide elements  76   a ,  78   a  causes the counter-braking element  26   a  to be displaced translationally, wherein a rotation of the counter-braking element  26   a  is superposed on the translation ( FIG. 4 ). The counter-braking element  26   a  in this case is moved by the braking element  22   a , against a spring force of a spring element  82   a  of the braking unit  12   a , away from the braking element  22   a . The spring element  82   a  is provided to apply a spring force to the counter-braking element  26   a  in the direction of the braking element  22   a . In this case, the spring element  82   a  is supported with one end on a collar  84   a  of the brake carrier element  80   a  and, with a further end, the spring element  82   a  is supported on the counter-braking element  26   a . It can thus be ensured that, after removal of an actuating force, as a result of the spring force of the spring element  82   a , the counter-braking element  26   a  is moved in the direction of the braking element  22   a  and is pressed on to the latter. The braking unit  12   a  is thus brought into a braking position. 
     Furthermore, the operating unit  16   a  comprises at least one switch-on blocking element  28   a , which is mounted such that it can pivot on the operating element  14   a . It is also conceivable, however, for the switch-on blocking element  28   a  to be mounted so as to be translationally movable on the operating element  14   a . The switch-on blocking element  28   a  is provided to prevent insofar as possible an unintentional movement of the operating element  14   a  in the direction of the power tool housing  34   a . The switch-on blocking element  28   a  is thus provided to prevent, insofar as possible, the power tool  30   a  being unintentionally put into operation. Furthermore, the operating unit  16   a  comprises a biased-off device  86   a , which is provided to bring the operating element  14   a  back into an initial position if an action of force is interrupted, or if a minimum actuating force exerted by an operator upon the operating element  14   a  is not attained. As a result of this, an electric power supply to the drive unit  40   a  is interrupted, and the braking unit  12   a  brakes the drive shaft  52   a , or the spindle  44   a  driven in rotation, by means of a combined action of the braking element  22   a  and of the counter-braking element  26   a , and thus brakes the working tool  46   a . The biased-off device  86   a  in this case comprises a spring element (not represented in greater detail here), which is disposed on the pivot bearing region  88   a  of the operating element  14   a , and which applies a spring force to the operating element  14   a  in the direction of an initial position of the operating element  14   a . The spring element of the biased-off device  86   a  thus acts upon the operating element  14   a  in a direction away from the power tool housing  34   a.    
     Alternative exemplary embodiments are represented in  FIGS. 5 to 18 . Components, features and functions that remain substantially the same are denoted by essentially the same references. To differentiate the exemplary embodiments, the letters a to n are appended to the references of the exemplary embodiments. The description that follows is limited essentially to the differences in respect of the first exemplary embodiment, described in  FIGS. 1 to 4 , and reference may be made to the description of the first exemplary embodiment in  FIGS. 1 to 4  in respect of components, features and functions that remain the same. 
       FIG. 5  shows an alternative power tool  30   b , having an alternative power tool braking device  10   b . The design of the power tool  30   b  is at least substantially similar to that of the power tool  30   a  described in  FIGS. 1 to 4 . The power tool braking device  10   b  comprises at least one braking unit  12   b , and comprises at least one operating unit  16   b , having a movably mounted operating element  14   b , for activating and/or deactivating the braking unit  12   b . The operating element  14   b  is mounted such that it can pivot about a movement axis  18   b  of the operating element  14   b . The movement axis  18   b  extends at least substantially transversely in relation to a rotation axis  20   b  of a rotatably mounted braking element  22   b  of the braking unit  12   b . A pivot bearing region  88   b  of the operating element  14   b  in this case is disposed at an end of the operating element  14   b  that faces away from a transmission housing  38   b  of a power tool housing  34   b  of the power tool  30   b.    
     The operating unit  16   b  additionally has a switch actuating element  56   b , which is movably mounted in a power tool housing  34   b  of the power tool  30   b . The operating element  14   b  comprises an actuating region, for actuating the switch actuating element  56   b . The operating unit  16   b  has at least one movement coupling element  24   b , for coupling the operating element  14   b  to a counter-braking element  26   b  of the braking unit  12   b . The movement coupling element  24   b  is mounted in a translationally movable manner in the power tool housing  34   b . Moreover, the operating unit  16   b  comprises a connecting element  90   b , which is provided to connect the movement coupling element  24   b  and the switch actuating element  56   b  to each other. The connecting element  90   b  is connected, with one end, to the movement coupling element  24   b , via a link element  92   b  of the operating unit  16   b  and, with a further end, the connecting element  90   b  is connected to the switch actuating element  56   b , via a further link element  94   b  of the operating unit  16   b . Thus, the operating element  14   b , as a result of a movement in the direction of the power tool housing  34   b , by means of the switch actuating element  56   b  and the connecting element  90   b , is coupled to the counter-braking element  26   b  via the movement coupling element  24   b . In respect of further functions and features of the power tool braking device  10   b  and the power tool  30   b , reference may be made to the exemplary embodiment described in  FIGS. 1 to 4 . 
       FIG. 6  shows an alternative power tool  30   c , having an alternative power tool braking device  10   c . The design of the power tool  30   c  is at least substantially similar to that of the power tool  30   a  described in  FIGS. 1  to  4 . The power tool braking device  10   c  comprises at least one braking unit  12   c , and comprises at least one operating unit  16   c , having a movably mounted operating element  14   c , for activating and/or deactivating the braking unit  12   c . The operating element  14   c  is mounted such that it can pivot about a movement axis  18   c  of the operating element  14   c . The movement axis  18   c  extends at least substantially transversely in relation to a rotation axis  20   c  of a rotatably mounted braking element  22   c  of the braking unit  12   c . A pivot bearing region  88   c  of the operating element  14   c  in this case is disposed at an end of the operating element  14   c  that faces away from a transmission housing  38   c  of a power tool housing  34   c  of the power tool  30   c.    
     The operating unit  16   c  additionally has at least one switch-on blocking element  28   c , which is connected to a movement coupling element  24   c  of the operating unit  16   c . The switch-on blocking element  28   c  in this case is connected to the movement coupling element  24   c  by means of a connecting element  90   c  and at least two link elements  92   c ,  94   c  of the operating unit  16   c . The braking unit  12   c  is thus brought from a braking position into a release position by means of an actuation of the switch-on blocking element  28   c . Moreover, a movement capability of the operating element  14   c , in the direction of the power tool housing  34   c , is released as a result of the actuation of the switch-on blocking element  28   c . In respect of further functions and features of the power tool braking device  10   c  and the power tool  30   c , reference may be made to the exemplary embodiment described in  FIGS. 1 to 4 . 
       FIG. 7  shows an alternative power tool  30   d , having an alternative power tool braking device  10   d . The design of the power tool  30   d  is at least substantially similar to that of the power tool  30   a  described in  FIGS. 1 to 4 . The power tool braking device  10   d  comprises at least one braking unit  12   d , and comprises at least one operating unit  16   d , having a movably mounted operating element  14   d , for activating and/or deactivating the braking unit  12   d . The operating element  14   d  is mounted such that it can pivot about a movement axis  18   d  of the operating element  14   d . The movement axis  18   d  extends at least substantially transversely in relation to a rotation axis  20   d  of a rotatably mounted braking element  22   d  of the braking unit  12   d . A pivot bearing region  88   d  of the operating element  14   d  in this case is disposed at an end of the operating element  14   d  that faces toward a transmission housing  38   d  of a power tool housing  34   d  of the power tool  30   d.    
     The operating element  14   d  comprises an inclined face  62   d , which is provided to act in combination with an actuating face  60   d  of a movement coupling element  24   d  of the operating unit  16   d  that is realized to correspond to the inclined face  62   d , as a result of a movement of the operating element  14   d  in the direction of the power tool housing  34   d . As a result of the combined action of the inclined face  62   d  and the actuating face  60   d , the movement coupling element  24   d , mounted so as to be translationally movable, is displaced in the direction of the transmission housing  38   d . As a result of this, a counter-braking element  26   d  of the braking unit  12   d  is moved away from the braking element  22   d , and the braking unit  12   d  is brought into a release position. It is also conceivable, however, for the braking unit  12   d  to be motionally connected to the operating unit  16   d  by another mechanism considered appropriate by persons skilled in the art, as described for example, in  FIGS. 5 and 6 . In respect of further functions and features of the power tool braking device  10   d  and the power tool  30   d , reference may be made to the exemplary embodiment described in  FIGS. 1 to 4 . 
       FIG. 8  shows an alternative power tool  30   e , having an alternative power tool braking device  10   e . The design of the power tool  30   e  is at least substantially similar to that of the power tool  30   a  described in  FIGS. 1 to 4 . The power tool braking device  10   e  comprises at least one braking unit  12   e , and comprises at least one operating unit  16   e , having a movably mounted operating element  14   e , for activating and/or deactivating the braking unit  12   e . The operating element  14   e  is mounted such that it can pivot about a movement axis  18   e  of the operating element  14   e . The movement axis  18   e  extends at least substantially parallelwise in relation to a rotation axis  20   e  of a rotatably mounted braking element  22   e  of the braking unit  12   e . It is also conceivable, however, for the braking unit  12   e  to be motionally connected to the operating unit  16   e  by another mechanism considered appropriate by persons skilled in the art, as described for example, in  FIGS. 5 and 6 . In respect of further functions and features of the power tool braking device  10   e  and the power tool  30   e , reference may be made to the exemplary embodiment described in  FIGS. 1 to 4 . 
       FIG. 9  shows an alternative operating unit  16   f  of a power tool braking device  10   f . The power tool braking device  10   f  in this case is disposed in a power tool, not represented in greater detail, whose design is at least substantially similar to that of the power tool  30   a  described in  FIGS. 1 to 4 . The power tool braking device  10   f  comprises at least one braking unit  12   f , and comprises at least one operating unit  16   f , having a movably mounted operating element (not represented in greater detail here), for activating and/or deactivating the braking unit  12   f . In this case, the design of the braking unit  12   f , or of the operating element, is at least substantially similar to that of the braking unit  12   a , or operating element  14   a , described in  FIGS. 1 to 4 . The braking unit  12   f  thus comprises at least one coupling extension  70   f , which is disposed on a counter-braking element (not represented in greater detail here) of the braking unit  12   f . In addition, a brake carrier element  80   f  of the braking unit  12   f  comprises at least one groove-type recess  72   f , in which the coupling extension  70   f  engages. 
     The operating unit  16   f  additionally has at least one movement coupling element  24   f , realized as a cable pull element, for coupling the operating element to the counter-braking element of the braking unit  12   f . The movement coupling element  24   f  is connected to the coupling extension  70   f  and to a ramp element  98   f  that bears against an inclined face (not represented in greater detail here) of the operating element. The ramp element  98   f  is mounted so as to be translationally movable. Moreover, the operating unit  16   f  has a deflection element  96   f , realized as a roller. The deflection element  96   f  is provided to deflect the movement coupling element  24   f  that is realized as a cable pull element. The movement coupling element  24   f  thus passes around the deflection element  96   f , at least partially. As a result of a movement of the operating element in the direction of a power tool housing (not represented in greater detail here) of the power tool, the ramp element  98   f  slides on the inclined face, with a face of the ramp element  98   f  that faces toward the inclined face. As a result of this, the movement coupling element  24   f  realized as a cable pull element is subjected to a tensile force in a direction away from the braking unit  12   f , and is moved in the direction away from the braking unit  12   f . As a result of this, the coupling extension  70   f  slides in the groove-type recess  72   f . The counter-braking element in this case executes a translation, on which a rotation is superposed. The counter-braking element is thus moved away from the braking element. 
       FIG. 10  shows an alternative operating unit  16   g  of a power tool braking device  10   g . The power tool braking device  10   g  in this case is disposed in a power tool, not represented in greater detail, whose design is at least substantially similar to that of the power tool  30   a  described in  FIGS. 1 to 4 . The power tool braking device  10   g  comprises at least one braking unit  12   g , and comprises at least one operating unit  16   g , having a movably mounted operating element (not represented in greater detail here), for activating and/or deactivating the braking unit  12   g . In this case, the design of the braking unit  12   g , or of the operating element, is at least substantially similar to that of the braking unit  12   a , or operating element  14   a , described in  FIGS. 1 to 4 . The braking unit  12   g  thus comprises at least one coupling extension  70   g , which is disposed on a counter-braking element (not represented in greater detail here) of the braking unit  12   g . In addition, a brake carrier element  80   g  of the braking unit  12   g  comprises at least one groove-type recess  72   g , in which the coupling extension  70   g  engages. 
     The operating unit  16   g  additionally has at least one movement coupling element  24   g , realized as a rotary lever element, for coupling the operating element to the counter-braking element of the braking unit  12   g . The movement coupling element  24   g  realized as a rotary lever element has, at one end, a groove-type receiving recess  100   g , in which the coupling extension  70   g  engages. Moreover, the movement coupling element  24   g  realized as a rotary lever element is connected, by a further end, to the operating element. As a result of a movement of the operating element in the direction of a power tool housing (not represented in greater detail here) of the power tool, the movement coupling element  24   g  realized as a rotary lever element is rotated about a rotation axis  102   g  of the movement coupling element  24   g . As a result of this, the coupling extension  70   g  is moved in the groove-type recess  72   g  of the brake carrier element  80   g . The counter-braking element in this case executes a translation, on which a rotation is superposed. The counter-braking element is thus moved away from the braking element. 
       FIG. 11  shows an alternative operating unit  16   h  of a power tool braking device  10   h . The power tool braking device  10   h  in this case is disposed in a power tool, not represented in greater detail, whose design is at least substantially similar to that of the power tool  30   a  described in  FIGS. 1 to 4 . The power tool braking device  10   h  comprises at least one braking unit  12   h , and comprises at least one operating unit  16   h , having a movably mounted operating element (not represented in greater detail here), for activating and/or deactivating the braking unit  12   h . In this case, the design of the braking unit  12   h , or of the operating element, is at least substantially similar to that of the braking unit  12   a , or operating element  14   a , described in  FIGS. 1 to 4 . The braking unit  12   h  thus comprises at least one coupling extension  70   h , which is disposed on a counter-braking element (not represented in greater detail here) of the braking unit  12   h . In addition, a brake carrier element  80   h  of the braking unit  12   h  comprises at least one groove-type recess  72   h , in which the coupling extension  70   h  engages. 
     The operating unit  16   h  additionally has at least one movement coupling element  24   h , realized as a rotary lever element, for coupling the operating element to the counter-braking element of the braking unit  12   h . In addition, the operating unit  16   h  comprises at least one cable pull element  104   h , which is connected to one end of the movement coupling element  24   h  realized as a rotary lever element. By another end, at which the movement coupling element  24   h  realized as a rotary lever element has a groove-type receiving recess  100   h , the movement coupling element  24   h  is connected to the coupling extension  70   f  as a result of the coupling extension  70   h  engaging in the groove-type receiving recess  100   h . The cable pull element  104   h  is connected to a ramp element  98   h  that bears against an inclined face (not represented in greater detail here) of the operating element. The ramp element  98   h  is mounted so as to be translationally movable. As a result of a movement of the operating element in the direction of a power tool housing (not represented in greater detail here) of the power tool, the ramp element  98   h  slides on the inclined face, with a face of the ramp element  98   h  that faces toward the inclined face. As a result of this, the cable pull element  104   h  is subjected to a tensile force in a direction away from the braking unit  12   h , and is moved in the direction away from the braking unit  12   h . As a result of this, the movement coupling element  24   h  realized as a rotary lever element is rotated about a rotation axis  102   h  of the movement coupling element  24   g . As a result of this, the coupling extension  70   h  slides in the groove-type recess  72   h  of the brake carrier element  80   h . The counter-braking element in this case executes a translation, on which a rotation is superposed. The counter-braking element is thus moved away from the braking element. 
       FIG. 12  shows an alternative operating unit  16   i  of a power tool braking device  10   i . The power tool braking device  10   i  in this case is disposed in a power tool, not represented in greater detail, whose design is at least substantially similar to that of the power tool  30   a  described in  FIGS. 1 to 4 . The power tool braking device  10   i  comprises at least one braking unit  12   i , and comprises at least one operating unit  16   i , having a movably mounted operating element (not represented in greater detail here), for activating and/or deactivating the braking unit  12   i . In this case, the design of the braking unit  12   i , or of the operating element, is at least substantially similar to that of the braking unit  12   a , or operating element  14   a , described in  FIGS. 1 to 4 . The braking unit  12   i  thus comprises at least one coupling extension  70   i , which is disposed on a counter-braking element (not represented in greater detail here) of the braking unit  12   i . In addition, a brake carrier element  80   i  of the braking unit  12   i  comprises at least one groove-type recess  72   i , in which the coupling extension  70   i  engages. 
     The operating unit  16   i  additionally has at least one movement coupling element  24   i , realized as a rack element, for coupling the operating element to the counter-braking element of the braking unit  12   i . The movement coupling element  24   i  realized as a rack element is mounted in a translationally movable manner in a power tool housing (not represented in greater detail here) of the power tool. Moreover, the operating unit  16   i  comprises at least one gear wheel element  106   i , which is rotatably mounted in the power tool housing. The gear wheel element  106   i  meshes, on the one hand, with the movement coupling element  24   i  realized as a rack element and, on the other hand, with a rack (not represented in greater detail here) disposed on the operating element. It is also conceivable, however, for the operating element, as an alternative to having the rack, to have a gear wheel element that is rotatably mounted on the operating element. As a result of a movement of the operating element in the direction of the power tool housing, the rack disposed on the operating element meshes with the gear wheel element  106   i . As a result of this, the gear wheel element  106   i  is put into rotation, and thus moves the movement coupling element  24   i  realized as a rack element. The counter-braking element in this case executes a translation, on which a rotation is superposed. The counter-braking element is thus moved away from the braking element. 
       FIG. 13  shows an alternative operating unit  16   j  of a power tool braking device  10   j . The power tool braking device  10   j  in this case is disposed in a power tool, not represented in greater detail, whose design is at least substantially similar to that of the power tool  30   a  described in  FIGS. 1 to 4 . The power tool braking device  10   j  comprises at least one braking unit  12   j , and comprises at least one operating unit  16   j , having a movably mounted operating element (not represented in greater detail here), for activating and/or deactivating the braking unit  12   j . In this case, the design of the braking unit  12   j , or of the operating element, is at least substantially similar to that of the braking unit  12   a , or operating element  14   a , described in  FIGS. 1 to 4 . The braking unit  12   j  thus comprises at least one coupling extension  70   j , which is disposed on a counter-braking element (not represented in greater detail here) of the braking unit  12   j . In addition, a brake carrier element  80   j  of the braking unit  12   j  comprises at least one groove-type recess  72   j , in which the coupling extension  70   j  engages. 
     The operating unit  16   j  additionally has at least one movement coupling element  24   j , realized as a rack element, for coupling the operating element to the counter-braking element of the braking unit  12   j . The movement coupling element  24   j  realized as a rack element is mounted in a translationally movable manner in a power tool housing (not represented in greater detail here) of the power tool. Moreover, the operating unit  16   j  comprises at least one gear wheel element (not represented in greater detail here), which is rotatably mounted in the power tool housing. The gear wheel element in this case meshes with the movement coupling element  24   j  realized as a rack element. The operating unit  16   j  additionally comprises at least one pulley element  108   j , which is connected to the gear wheel element in a rotationally fixed manner. The operating unit  16   j  additionally comprises at least one cable pull element  104   j , which can be rolled up by means of the pulley element  108   j . The cable pull element  104   j  is additionally connected to a ramp element  98   j  that bears against an inclined face (not represented in greater detail here) of the operating element. The ramp element  98   j  is mounted so as to be translationally movable. As a result of a movement of the operating element in the direction of a power tool housing (not represented in greater detail here) of the power tool, the ramp element  98   j  slides on the inclined face, with a face of the ramp element  98   j  that faces toward the inclined face. As a result of this, the cable pull element  104   j  is subjected to a tensile force in a direction away from the braking unit  12   j , and is moved in the direction away from the braking unit  12   j . In this case, the pulley element  108   j  and the gear wheel element are put into rotation. Moreover, the movement coupling element  24   j  realized as a rack element is moved as a result of the meshing with the gear wheel element. The counter-braking element in this case executes a translation, on which a rotation is superposed. The counter-braking element is thus moved away from the braking element. 
       FIG. 14  shows an alternative operating unit  16   k  of a power tool braking device  10   k . The power tool braking device  10   k  in this case is disposed in a power tool, not represented in greater detail, whose design is at least substantially similar to that of the power tool  30   a  described in  FIGS. 1 to 4 . The power tool braking device  10   k  comprises at least one braking unit  12   k , and comprises at least one operating unit  16   k , having a movably mounted operating element (not represented in greater detail here), for activating and/or deactivating the braking unit  12   k . In this case, the design of the braking unit  12   k , or of the operating element, is at least substantially similar to that of the braking unit  12   a , or operating element  14   a , described in  FIGS. 1 to 4 . The braking unit  12   k  thus comprises at least one coupling extension  70   k , which is disposed on a counter-braking element (not represented in greater detail here) of the braking unit  12   k . In addition, a brake carrier element  80   k  of the braking unit  12   k  comprises at least one groove-type recess  72   k , in which the coupling extension  70   k  engages. 
     The operating unit  16   k  additionally has at least one movement coupling element  24   k , realized as a contour element, for coupling the operating element to the counter-braking element of the braking unit  12   k . The movement coupling element  24   k  realized as a contour element comprises a helix-type recess  114   k , in which the coupling extension  70   k  engages. Moreover, the operating unit  16   k  comprises at least one pulley element  108   k , on which a cable pull element  104   k  of the operating unit  16   k  can be rolled up. The movement coupling element  24   k , realized as a contour element, and the pulley element  108   k  are rotatably mounted in a power tool housing (not represented in greater detail here) of the power tool. The cable pull element  104   k  is connected to a ramp element  98   k  that bears against an inclined face (not represented in greater detail here) of the operating element. The ramp element  98   k  is mounted so as to be translationally movable. As a result of a movement of the operating element in the direction of a power tool housing, the ramp element  98   k  slides on the inclined face, with a face of the ramp element  98   k  that faces toward the inclined face. As a result of this, the cable pull element  104   k  is subjected to a tensile force in a direction away from the braking unit  12   k , and is moved in the direction away from the braking unit  12   k . In this case, the pulley element  108   k  and the movement coupling element  24   k  realized as a contour element are put into rotation. The coupling extension  70   k  slides in the helix-type recess  114   k  of the movement coupling element  24   k  realized as a contour element, as a result of which the counter-braking element executes a translation, on which a rotation is superposed. The counter-braking element is thus moved away from the braking element. 
       FIG. 15  shows an alternative operating unit  16   l  of a power tool braking device  10   l . The power tool braking device  10   l  in this case is disposed in a power tool, not represented in greater detail, whose design is at least substantially similar to that of the power tool  30   a  described in  FIGS. 1 to 4 . The power tool braking device  10   l  comprises at least one braking unit  12   l , and comprises at least one operating unit  16   l , having a movably mounted operating element (not represented in greater detail here), for activating and/or deactivating the braking unit  12   l . In this case, the design of the braking unit  12   l , or of the operating element, is at least substantially similar to that of the braking unit  12   a , or operating element  14   a , described in  FIGS. 1 to 4 . The braking unit  12   l  thus comprises at least one coupling extension  70   l , which is disposed on a counter-braking element (not represented in greater detail here) of the braking unit  12   l . In addition, a brake carrier element  80   l  of the braking unit  12   l  comprises at least one groove-type recess  72   l , in which the coupling extension  70   l  engages. 
     The operating unit  16   l  additionally has at least one movement coupling element  24   l , realized as a contour element, for coupling the operating element to the counter-braking element of the braking unit  12   l . The movement coupling element  24   l  realized as a contour element comprises a helix-type recess  114   l , in which the coupling extension  70   l  engages. Moreover, the operating unit  16   l  comprises at least one gear wheel element  106   l , which is connected in a rotationally fixed manner to the movement coupling element  24   l  realized as a contour element. The gear wheel element  106   l  and the movement coupling element  24   l  realized as a contour element are rotatably mounted in a power tool housing (not represented in greater detail here) of the power tool. The operating unit  16   l  additionally comprises at least one rack element  1121  and at least one cable pull element  104   l . The rack element  1121  in this case is translationally mounted in the power tool housing. The gear wheel element  106   l  meshes with the rack element  1121 . The cable pull element  104   l  is connected to a ramp element  98   l  that bears against an inclined face (not represented in greater detail here) of the operating element. The ramp element  98   l  is mounted so as to be translationally movable. As a result of a movement of the operating element in the direction of a power tool housing, the ramp element  98   l  slides on the inclined face, with a face of the ramp element  98   l  that faces toward the inclined face. As a result of this, the cable pull element  104   l  is subjected to a tensile force in a direction away from the braking unit  12   l , and is moved in the direction away from the braking unit  12   l . In this case, the rack element  1121  is moved translationally, and the gear wheel element  106   l  is put into rotation. As a result of this, the movement coupling element  24   l , connected in a rotationally fixed manner to the gear wheel element  106   l  and realized as a contour element, is likewise put into rotation. The coupling extension  70   k  slides in the helix-type recess of the movement coupling element  24   l  realized as a contour element, as a result of which the counter-braking element executes a translation, on which a rotation is superposed. The counter-braking element is thus moved away from the braking element. 
       FIG. 16  shows an alternative power tool  30   m , having an alternative power tool braking device  10   m . The design of the power tool  30   m  is at least substantially similar to that of the power tool  30   a  described in  FIGS. 1 to 4 . The power tool braking device  10   m  comprises at least one braking unit  12   m , and comprises at least one operating unit  16   m , having a movably mounted operating element  14   m , for activating and/or deactivating the braking unit  12   m . The operating element  14   m  is mounted such that it can pivot about a movement axis  18   m  of the operating element  14   m . The movement axis  18   m  extends at least substantially transversely in relation to a rotation axis  20   m  of a rotatably mounted braking element  22   m  of the braking unit  12   m . A pivot bearing region  88   m  of the operating element  14   m  in this case is disposed at an end of the operating element  14   m  that faces away from a transmission housing  38   m  of a power tool housing  34   m  of the power tool  30   m.    
     The operating unit  16   m  has at least one movement coupling element  24   m , for coupling the operating element  14   m  to a counter-braking element  26   m  of the braking unit  12   m . The movement coupling element  24   m  in this case is mounted in a translationally displaceable manner in the power tool housing  34   m . In respect of a movement of the movement coupling element  24   m  as a result of a movement of the operating element  14   m , reference may be made to the description of  FIGS. 1 to 4 . The movement coupling element  24   m  is connected to an actuating element  68   m  of the operating unit  16   m , for the purpose of moving a counter-braking element  26   m  of the braking unit  12   m . The actuating element  68   m  is mounted in the power tool housing  34   m  such that it can pivot about a movement axis of the actuating element  68   m . The movement axis of the actuating element  68   m  extends at least substantially transversely in relation to the rotation axis  20   m  of the braking element  22   m . In this case, the movement axis of the actuating element  68   m , as viewed in a projection plane into which the movement axis of the actuating element  68   m  and the rotation axis  20   m  of the braking element  22   m  are projected, extends at least substantially perpendicularly in relation to the rotation axis  20   m  of the braking element  22   m.    
     The actuating element  68   m  is additionally mounted by a link joint on the movement coupling element  24   m , in a movement transmission region  66   m  of the movement coupling element  24   m . The actuating element  68   m  is thus pivotally mounted on the movement coupling element  24   m  by means of a link joint. The link joint may be realized, for example, by means of a combined action of a pin, or a stud-type extension, and of a recess that corresponds to the pin, or to the stud-type extension, such as, for example, a link eye. The actuating element  68   m  is connected, by an end that faces away from the movement coupling element  24   m , to the counter-braking element  26   m . In this case, the end of the actuating element  68   m  that faces away from the movement coupling element  24   m  may be movably mounted on the counter-braking element  26   m , or the end of the actuating element  68   m  that faces away from the movement coupling element  24   m  may engage in a recess, or may bear against an extension of the counter-braking element  26   m , for the purpose of moving the counter-braking element  26   m  against a spring force of a spring element  82   m  of the braking unit  12   m.    
     The counter-braking element  26   m  is mounted in the power tool housing  34   m  so as to be translationally movable along the rotation axis  20   m  of the braking element  22   m . Moreover, the counter-braking element  26   m  is disposed in a rotationally fixed manner in the power tool housing  34   m . Owing to the fact that the counter-braking element  26   m  is disposed in a rotationally fixed manner in the power tool housing  34   m , a rotational movement of the counter-braking element  26   m  about the rotation axis  20   m  of the braking element  22   m , relative to the power tool housing  34   m , is prevented. It is also conceivable, however, for the counter-braking element  26   m , as an alternative to being mounted in a translationally movable manner in the power tool housing  34   m , to be mounted such that it can pivot about a pivot axis of the counter-braking element  26   m  that extends at least substantially transversely in relation to the rotation axis  20   m  of the braking element  22   m.    
     For the purpose of bringing the braking element  22   m  and/or the counter-braking element  26   m  out of a braking position and into a release position, an operator actuates the operating element  14   m , which is thus moved about the movement axis  18   m  of the operating element  14   m . As a result of a translational movement of the movement coupling element  24   m  caused by the movement of the operating element  14   m , the actuating element  68   m  is pivoted about the movement axis of the actuating element  68   m , because of the link-type connection between the movement coupling element  24   m  and the actuating element  68   m , and because of the pivoted mounting of the actuating element  68   m . As a result of the pivot movement of the actuating element  68   m  and the connection between the actuating element  68   m  and the counter-braking element  26   m , the counter-braking element  26   m  is moved away from the braking element  22   m , against a spring force of the spring element  82   m  ( FIG. 17 ). The counter-braking element  26   m , or the braking element  22   m , is thus brought into a release position. After removal of a force, applied by an operator, upon the operating element  14   m , and consequently after removal of an action of force upon the movement coupling element  24   m  and upon the actuating element  68   m , the counter-braking element  26   m  is moved in the direction of the braking element  22   m , or pressed on to the braking element  22   m , by a spring force of the spring element  82   m . The counter-braking element  26   m , or the braking element  22   m , is thus brought back into a braking position. In respect of further functions and features of the power tool braking device  10   m  and the power tool  30   m , reference may be made to the exemplary embodiment described in  FIGS. 1 to 4 . In principle, however, it is also conceivable, as an alternative to a movement coupling mechanism described in  FIGS. 16 and 17  being used for moving the counter-braking element  26   m , for the movement coupling mechanisms described in  FIG. 9  to be used, and/or for the design of the operating element  14   m  to correspond to a design described in  FIGS. 5 to 8 . 
       FIG. 18  shows an alternative power tool  30   n , having an alternative power tool braking device  10   n . The design of the power tool  30   n  is at least substantially similar to that of the power tool  30   a  described in  FIGS. 1 to 4 . The power tool braking device  10   n  comprises at least one braking unit  12   n , and comprises at least one operating unit  16   n , having a movably mounted operating element  14   n , for activating and/or deactivating the braking unit  12   n . The operating element  14   n  is mounted such that it can pivot about a movement axis  18   n  of the operating element  14   n . The movement axis  18   n  extends at least substantially parallelwise in relation to a rotation axis  20   n  of a rotatably mounted braking element  22   n  of the braking unit  12   n . A pivot bearing region  88   n  of the operating element  14   n  in this case is disposed at an end of the operating element  14   n  that faces away from a transmission housing  38   n  of a power tool housing  34   n  of the power tool  30   n.    
     For the purpose of activating and/or deactivating the braking unit  12   n , the operating element  14   n  comprises at least one inclined face  62   n . The inclined face  62   n  is disposed on a side of the operating element  14   n  that faces toward the braking unit  12   n . The operating unit  16   n  additionally comprises at least one actuating element  68   n . The actuating element  68   n  is mounted in the power tool housing  34   n  such that it can pivot about a movement axis of the actuating element  68   n . The movement axis of the actuating element  68   n  extends at least substantially transversely in relation to the rotation axis  20   n  of the braking element  22   n . In this case, the movement axis of the actuating element  68   n , as viewed in a projection plane into which the movement axis of the actuating element  68   n  and the rotation axis  20   n  of the braking element  22   n  are projected, extends at least substantially perpendicularly in relation to the rotation axis  20   n  of the braking element  22   n . The actuating element  68   n  additionally comprises a movement coupling region, at an end of the actuating element  68   n  that faces toward the operating element  14   n . The movement coupling region of the actuating element  68   n  in this case may be realized as an inclined face, as a rolling element, etc, that is realized to correspond to the inclined face  62   n  of the operating element  14   n . Thus, for the purpose of moving a counter-braking element  26   n  of the braking unit  12   n , in at least one state, the inclined face  62   n  bears against the movement coupling region of the actuating element  68   n . As a result of this, the actuating element  68   n  is moved in dependence on a movement of the operating element  14   n.    
     The counter-braking element  26   n  is mounted in the power tool housing  34   n  so as to be translationally movable along the rotation axis  20   n  of the braking element  22   n . Moreover, the counter-braking element  26   n  is disposed in a rotationally fixed manner in the power tool housing  34   n . Owing to the fact that the counter-braking element  26   n  is disposed in a rotationally fixed manner in the power tool housing  34   n , a rotational movement of the counter-braking element  26   n  about the rotation axis  20   n  of the braking element  22   n , relative to the power tool housing  34   n , is prevented. It is also conceivable, however, for the counter-braking element  26   n , as an alternative to being mounted in a translationally movable manner in the power tool housing  34   n , to be mounted such that it can pivot about a pivot axis of the counter-braking element  26   n  that extends at least substantially transversely in relation to the rotation axis  20   n  of the braking element  22   n.    
     For the purpose of bringing the braking element  22   n  and/or the counter-braking element  26   n  out of a braking position and into a release position, an operator actuates the operating element  14   n , which is thus moved about the movement axis  18   n  of the operating element  14   n . In this case, a combined action of the inclined face  62   n  of the operating element  14   n  and of the movement coupling region of the actuating element  68   n  causes the actuating element  68   n  to be pivoted about the movement axis of the actuating element  86   n . As a result of the pivot movement of the actuating element  68   n  and the connection between the actuating element  68   n  and the counter-braking element  26   n , the counter-braking element  26   n  is moved away from the braking element  22   n , against a spring force of a spring element  82   n  of the braking unit  12   n . The counter-braking element  26   n , or the braking element  22   n , is thus brought into a release position. After removal of a force, applied by an operator, upon the operating element  14   n , and consequently after removal of an action of force upon the actuating element  68   n , the counter-braking element  26   n  is moved in the direction of the braking element  22   n , or pressed on to the braking element  22   n , by a spring force of the spring element  82 . The counter-braking element  26   n , or the braking element  22   n , is thus brought back into a braking position. In respect of further functions and features of the power tool braking device  10   n  and the power tool  30   n , reference may be made to the exemplary embodiment described in  FIGS. 1 to 4 . In principle, however, it is also conceivable, as an alternative to a movement coupling mechanism described in  FIG. 18  being used for moving the counter-braking element  26   n , for the movement coupling mechanisms described in  FIGS. 9 to 15  be used, and/or for the design of the operating element  14   n  to correspond to a design described in  FIGS. 5 to 8 .