Patent Publication Number: US-2023158656-A1

Title: Press-on element for a power tool

Description:
The present invention relates to a power tool, in particular a rotary hammer or combination hammer, containing a percussion-mechanism apparatus for generating percussion pulses on a tool, having a basic body for receiving a rear end of the tool, at least one first and second locking element, each arranged lying in radial openings of the basic body in a reversible manner in a locking position or release position, wherein, in the locking position, the rear end of the tool is held in the basic body and, in the release position, the rear end of the tool can be removed from the basic body, a locking ring for holding the at least first and second locking elements in the locking position, and a press-on element for guiding the at least first and second locking elements in a first axial direction and a second axial direction. 
     BACKGROUND 
     Power tools in the form of a rotary hammer or combination hammer of the type stated at the outset are known in principle from the prior art. Rotary hammers or combination hammers usually have a tool fitting for receiving and holding a tool on the power tool. The tool fittings transmit the torque to the tools that is generated in the drive of the power tools, ensure the transmission of percussion pulses from a percussion-mechanism apparatus to the substrate by allowing limited axial movements, and prevent the tools from falling out of the power tools. 
     SUMMARY OF THE INVENTION 
     The components of the tool fitting are exposed to high dynamic vibrations due to percussion-mechanism pulses at high frequencies. If the tools are accelerated by percussion pulses from the percussion mechanism, but this percussion energy cannot be passed on to a substrate to be removed, this is known as blank tool percussions. These blank tool percussions can cause considerable damage to the power tool, since the energy of the percussion pulses is not transferred to the substrate (that is to say material) to be machined, but is degraded on the components of the power tool, and in particular on the tool fitting. 
     It is an object of the present invention to provide a power tool which provides an improved power tool in which damage to the components of the power tool due to blank tool percussions can be reduced. 
     The present invention provides a power tool, in particular a rotary hammer or combination hammer, containing a percussion-mechanism apparatus for generating percussion pulses on a tool, having a basic body for receiving a rear end of the tool, at least one first and second locking element, each arranged lying in radial openings of the basic body in a reversible manner in a locking position or release position, wherein, in the locking position, the rear end of the tool is held in the basic body and, in the release position, the rear end of the tool can be removed from the basic body, a locking ring for holding the at least first and second locking elements in the locking position, and a press-on element for guiding the at least first and second locking elements in a first axial direction and a second axial direction. 
     According to the invention, there is provision that the press-on element consists at least partially of an elastic material. In this way, vibrations on components of the tool fitting that are generated by blank tool percussions can be damped. Owing to the damped vibrations, the components of the tool fitting are less stressed. 
     According to an advantageous embodiment of the present invention, it may be possible for the press-on element to contain at least one first receiving region for at least partially receiving the at least first and second locking elements. This allows effective transmission of vibrations from the locking elements to the vibration-absorbing press-on element to be achieved. 
     According to a further advantageous embodiment of the present invention, it may be possible for the press-on element to contain at least one connecting element for rotationally fixedly connecting the press-on element to an actuating cap. The nonrotational connection can prevent unwanted rotation of the press-on element relative to the locking elements. 
     According to an advantageous embodiment of the present invention, it may be possible for the at least one receiving region of the press-on element to contain a holding device for re-releasably holding the at least first and second locking elements in the receiving region. In this way, the respective locking element can be re-releasably connected to the press-on element in a simple manner. 
     According to a further advantageous embodiment of the present invention, it may be possible for the holding device to be designed in the form of a first and second elastically deformable lip element, wherein a respective freely movable end of the first and second lip elements are aligned with one another so that, through a cutout between the first and second lip elements, the at least first and second locking element can be at least partially received in the at least one receiving region. As a result, the locking element and the press-on element can be firmly connected to one another to a certain extent. It can thus be ensured that when the press-on element is moved in an axial direction, the locking element is pulled along by the press-on element. 
     According to an advantageous embodiment of the present invention, it may be possible for the at least one receiving region of the press-on element to contain a spring device for exerting a force in a first axial direction on the at least one pawl element. In this way, the press-on element helps to move the first and second locking elements from the release position back into the locking position. 
     According to a further advantageous embodiment of the present invention, it may be possible for the spring device to be designed in the form of an elastically deformable elevation in a first axial direction. 
     Further advantages will become apparent from the following description of the figures. Various exemplary embodiments of the present invention are illustrated in the figures. The figures, the description and the claims contain numerous features in combination. A person skilled in the art will expediently also consider the features individually and combine them to form useful further combinations. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the figures, identical and similar components are denoted by the same reference signs. In the figures: 
         FIG.  1    shows a schematic side view of a power tool in the form of a rotary hammer; 
         FIG.  2    shows a lateral sectional view of an actuating cap, a first and second locking element, a basic body, a tool and a press-on element according to a first embodiment; 
         FIG.  3    shows a detail view of the basic body, the locking element, a locking ring and the press-on element; 
         FIG.  4   a    shows a first perspective view of the press-on element according to a first embodiment; 
         FIG.  4   b    shows a second perspective view of the press-on element according to the first embodiment; 
         FIG.  5    shows a front sectional view of the actuating cap, the first and second locking elements, the basic body, the tool and the press-on element according to the first embodiment; 
         FIG.  6    shows a perspective view of the locking element according to a first embodiment; 
         FIG.  7   a    shows a first perspective view of the actuating cap; 
         FIG.  7   b    shows a second perspective view of the actuating cap; 
         FIG.  8    shows a perspective rear view of the locking ring; 
         FIG.  9    shows a perspective front view of the basic body according to a first embodiment; 
         FIG.  10    shows a lateral sectional view of the actuating cap, the first and second locking elements, the basic body, the tool and the press-on element according to a second embodiment; 
         FIG.  11    shows a plan view of the basic body, the locking ring, the first locking element and the press-on element according to the second embodiment; 
         FIG.  12   a    shows a lateral sectional view of the basic body, the locking ring, the first and second locking elements and the press-on element according to the second embodiment with the locking elements in a first position; 
         FIG.  12   b    shows a lateral sectional view of the basic body, the locking ring, the first and second locking elements and the press-on element according to the second embodiment with the locking elements in a second position; 
         FIG.  12   c    shows a lateral sectional view of the basic body, the locking ring, the first and second locking elements and the press-on element according to the second embodiment with the locking elements in a third position; 
         FIG.  13   a    shows a perspective front view of the press-on element in a second embodiment; 
         FIG.  13   b    shows a perspective rear view of the press-on element in a second embodiment; 
         FIG.  14   a    shows a perspective front view of the actuating cap according to the second embodiment; 
         FIG.  14   b    shows a perspective rear view of the actuating cap according to the second embodiment; 
         FIG.  15   a    shows a perspective front view of the locking ring; 
         FIG.  15   b    shows a perspective rear view of the locking ring; 
         FIG.  16   a    shows a first perspective view of a locking element according to the second embodiment; 
         FIG.  16   b    shows a second perspective view of a locking element according to the second embodiment; 
         FIG.  17    shows a perspective front view of the basic body according to a second embodiment; 
         FIG.  18    shows a front sectional view of the actuating cap, the first and second locking elements, the basic body, the tool and the press-on element according to the second embodiment; 
         FIG.  19   a    shows a perspective front view of the press-on element according to a third embodiment; 
         FIG.  19   b    shows a perspective rear view of the press-on element according to a third embodiment; 
         FIG.  20    shows a plan view of the basic body, the first locking element, the locking ring, the press-on element according to the third embodiment; 
         FIG.  21    shows a sectional view of the basic body, the first locking element, the locking ring and the press-on element according to the third embodiment; 
         FIG.  22    shows a front sectional view of the actuating cap, the first and second locking elements, the basic body, the tool and the press-on element according to the third embodiment; 
         FIG.  23   a    shows a first perspective view of a locking element according to the third embodiment; 
         FIG.  23   b    shows a second perspective view of a locking element according to the third embodiment; 
         FIG.  24   a    shows a lateral sectional view of the basic body, the locking ring, the first and second locking elements and the press-on element according to the third embodiment with the locking elements in a first position; 
         FIG.  24   b    shows a lateral sectional view of the basic body, the locking ring, the first and second locking elements and the press-on element according to the third embodiment with the locking elements in a second position; and 
         FIG.  24   c    shows a lateral sectional view of the basic body, the locking ring, the first and second locking elements and the press-on element according to the third embodiment with the locking elements in a third position. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS.  1  and  2    show a power tool  1  in the form of a rotary hammer. The power tool  1  can also be a hammer drill, combination hammer or the like, however. 
     The power tool  1  substantially contains a tool housing  2 , a handle  3 , a tool-fitting apparatus  4  and a power supply  5 . The tool-fitting apparatus  4  serves to receive and hold a tool  6 . The tool  6  is designed as a chisel in the figures and contains a front end  6   a  and a rear end  6   b.  The rear end  6   b  of the tool designed as a chisel is intended to be inserted into the tool-fitting apparatus  4 . The handle  3  serves to hold and guide the power tool  1 . The power supply  5  serves to supply the power tool  1  with electrical energy and is designed as a power cable in the present exemplary embodiment. The power supply  5  designed as a power cable can be connected to a mains power source, also called a socket. According to an alternative embodiment not shown in the figures, the power supply  5  can also be designed as an accumulator which can be releasably connected to the power tool  1  via a corresponding accumulator interface. 
     The interior of the tool housing  2  substantially contains a drive  7 , a percussion-mechanism apparatus  8 , a transmission apparatus  9  and a control apparatus  10 . As indicated in  FIG.  1   , the drive  7  is connected to the percussion-mechanism apparatus  8  via the transmission apparatus  9  in such a way that a torque generated by the drive  7  can be transmitted to the percussion-mechanism apparatus  8 . As a result of the torque transmitted from the drive  7  to the percussion-mechanism apparatus  8 , the percussion-mechanism apparatus  8  can generate percussion pulses. As further indicated in  FIG.  1   , the percussion-mechanism apparatus  8  is connected to the tool-fitting apparatus  4  in such a way that the percussion pulses are transmitted to the tool  6  positioned in the tool-fitting apparatus  4 . 
     The drive  7  is designed here as an electric motor, in particular as a brushless electric motor. 
     The tool housing  2  has a front end  2   a  and a rear end  2   b.  The tool-fitting apparatus  4  is positioned at the front end  2   a,  and the handle  3  is positioned at the rear end  2   b.    
     As shown in  FIG.  2   , the tool-fitting apparatus  4  in turn substantially contains an actuating cap  11 , an elongate basic body  12 , a locking ring  13 , first and second locking elements  14 ,  15  and a press-on element  16 . 
     The actuating cap  11  is designed substantially as a conical or cone-shaped sleeve which contains a first end  11   a  and a second end  11   b.    
     In  FIGS.  7   a  and  7   b   , the actuating cap  11  is shown in a first embodiment.  FIGS.  14   a  and  14   b    show the actuating cap  11  in a second embodiment. 
     The actuating cap  11  according to both the first and second embodiments has a step  11   d  on an inner lateral surface  11   c.  As will be described in detail later, the step  11   d  serves as a contact surface or support surface for the press-on element  16 . 
     The elongate basic body  12  serves to receive a rear end  6   b  of the tool  6  configured as a chisel. As will be described in detail below, the basic body  12  additionally serves to receive the locking ring  13 , the first and second locking elements  14 ,  15  and the press-on element  16  (see, e.g.,  FIG.  2   ). The basic body  12  is designed substantially in the form of a tube which has a first and second section  12   a,    12   b  (see, e.g.  FIGS.  9  and  17   ). Both the first section  12   a  and the second section  12   b  each contain first and second ends. The first section  12   a  has a smaller outside and inside diameter than the second section  12   b.  The first end of the first section  12   a  forms a front end of the basic body  12 . The second end of the first section  12   a  is connected to the first end of the second section  12   b.  The second end of the second section  12   b  in turn forms the rear end of the basic body  12 . First and second radial openings  17   a,    17   b  are present on the first section  12   a  of the basic body  12  (see, e.g,  FIG.  10   ). The first and second openings  17   a,    17   b  are elongate in form and positioned opposite one another. 
     In  FIG.  9   , the basic body  12  is shown in a first embodiment.  FIG.  17    shows the basic body  12  in a second embodiment. The basic body  12  according to the first and second embodiments differs substantially in that the basic body  12  of the  FIG.  9    embodiment contains an annular toothing  18  at the rear end. The toothing  18  serves for the rotationally fixed connection of the basic body  12  to a housing of the percussion-mechanism apparatus  8 . 
     The first and second locking elements  14 ,  15  substantially have a cuboidal basic body with a front end  19   a,  a rear end  19   b,  an upper end  19   c  and a lower end  19   d  (see, e.g.,  FIGS.  6 ,  10 ,  16     a ,  16   b    23   a  and  23   b ). The locking elements  14 ,  15  serve for re-releasably connecting the basic body  12  to the rear end  6   b  of the tool  6  when the rear end  6   b  of the tool  6  is located in the tool-fitting apparatus  4 . 
     In  FIG.  6    there are shown the locking elements  14 ,  15  in a first embodiment.  FIGS.  16   a  and  16   b    show the locking elements  14 ,  15  in a second embodiment. In  FIGS.  23   a  and  23   b    there are illustrated the locking elements  14 ,  15  in a third embodiment. 
     The locking elements  14 ,  15  can also be referred to as pawls and serve to re-releasably connect the tool  6  to the basic body  12 . 
     The locking elements  14 ,  15  shown in  FIG.  6    contains three steps  20  rising in direction A at the upper end. The first and second locking elements  14 ,  15  are identical to one another. 
     The locking elements  14 ,  15  shown in  FIGS.  16   a  and  16   b    according to the second embodiment have substantially a flat basic shape. At a front end  19   a,  the locking elements  14 ,  15  according to the second embodiment contain a flattened contact surface  21 . At a rear end  19   b,  the locking elements  14 ,  15  each contain a depression  22  on a left and a right lateral surface. The depression  22  can also be referred to as a groove or cutout. As will be described in detail later, these depressions  22  serve to establish a re-releasable connection with the press-on element  16 . 
     The locking elements  14 ,  15  shown in  FIGS.  23   a  and  23   b    according to the third embodiment substantially correspond to the locking elements  14 ,  15  according to the second embodiment, since they likewise have a flat basic shape. At a front end  19   a,  the locking elements  14 ,  15  according to the third embodiment likewise contain a flattened contact surface  21 . At a rear end  19   b,  the locking elements  14 ,  15  likewise each contain a depression  22  on a left and a right lateral surface. By contrast with the locking elements  14 ,  15  according to the second embodiment, the locking elements  14 ,  15  according to the third embodiment contain an elevation  23  which extends perpendicular to the longitudinal extent of the basic shape of the locking elements  14 ,  15 . In addition to the depressions  22  on the right and left lateral surfaces, this elevation  23  serves for an improved connection of the locking elements  14 ,  15  to the press-on element  16 . 
     The locking ring  13  is designed substantially as a sleeve and substantially serves to fix the first and second locking elements  14 ,  15  in a locking position in which the tool  6  is held by means of the locking elements  14 ,  15  in the basic body. 
       FIG.  8    shows the locking ring  13  in a first embodiment. The inner lateral surface  13   a  of the locking ring  13  according to the first embodiment is likewise designed in a stepped manner and corresponds to the upper end  19   c  of the first and second locking elements  14 ,  15  according to the first embodiment. 
     In  FIGS.  15   a  and  15   b   , the locking ring  13  is illustrated in a second embodiment. The locking ring  13  according to the second embodiment has a flattened plane on an inner lateral surface  13   a.  The angle of the flattened plane corresponds to the angle of the flattened contact surface  21  at the front end  19   a  of the locking elements  14 ,  15  according to the second embodiment. 
     In all of the embodiments, the press-on element  16  is designed substantially as a ring made of an elastic material (see, e.g,  4   a,    4   b,    13   a,    13   b,    19   a  and  19   b ). Here, the press-on element  16  designed as a ring is either completely or at least partially made of an elastic material. The elastic material may be an elastomer or rubber. The press-on element  16  shown in  FIGS.  4   a  and  4   b    according to a first embodiment is ring-shaped in form and has a first and a second surface side  16   a,    16   b.  On the first surface side  16   a,  a first and second cutout  24   a,    24   b  are provided, which are positioned opposite one another and extend radially over the entire first surface side  16   a.  The cutouts  24   a,    24   b  can also be referred to as a groove. An annular groove  25  is provided on the second surface side  16   b.    
     The press-on element  16  shown in  FIGS.  13   a  and  13   b    according to the second embodiment is likewise ring-shaped in form and also contains a first and second surface side  16   a,    16   b.  First and second cutouts  24   a,    24   b  are provided opposite one another on the first surface side  16   a.  The first and second cutouts  24   a,    24   b,  which can each also be referred to as a groove, extend in the radial direction. The cutouts  24   a,    24   b  serve as receiving regions for the respective rear end  19   b  of the locking elements  14 ,  15 . An elevation  26  is present in each of the first and second cutouts  24   a,    24   b.  The elevation  26  serves as a spring device to press the locking elements  14 ,  15  in direction B when the rear end  19   c  of the locking elements  14 ,  15  is located in the cutouts  24   a,    24   b  of the press-on element  16 . As shown in  FIGS.  11  and  13     b , the elevation  26  in the first and second cutouts  24   a,    24   b  extends in the axial direction B only up to half the height of the cutouts  24   a,    24   b.  In other words: The elevation  26  is half as high as the cutouts  24   a,    24   b.  As likewise shown in  FIGS.  11 ,  13     a  and  13   b , a lip  27  in each case protrudes from the left and right side of the cutouts  24   a,    24   b  over the cutouts  24   a,    24   b.  The lips  27  can be referred to as lip elements or as a holding device. The length of the lips  27  is chosen here so that an opening is created between the free ends of the lips  27 . As described in detail below, the lips  27  serve as a holding device for the locking elements  14 ,  15  on the press-on element  16 . 
     Furthermore, two connecting elements  28  in the form of elevations are present on the first surface side. The connecting elements  28  are arranged opposite one another and positioned offset by  90 ° to the two cutouts  24   a,    24   b.  The connecting elements  28  serve to rotationally fixedly connect the press-on element  16  to the actuating cap  11 . On the second surface side  16   b  of the press-on element  16 , two annular steps  28   a,    28   b  are provided. 
     The press-on element  16  shown in  FIGS.  19   a  and  19   b    according to the third embodiment is likewise ring-shaped in form and also contains a first and a second surface side  16   a,    16   b.  The design of the press-on element  16  according to the third embodiment is substantially identical to the press-on element  16  according to the second embodiment. Unlike the second embodiment, in the press-on element  16  according to the third embodiment, the lips  27  of the two cutouts  24   a,    24   b  are made longer, with the result that the respective free ends of the lips  27  almost close the cutouts  24   a,    24   b,  and almost no opening between the free ends of the lips  27  are provided over the respective cutouts  24   a,    24   b.  Moreover, according to the third embodiment, the press-on element  16  does not contain any elevation  26  in the two cutouts  24   a,    24   b.    
     In  FIGS.  2 ,  3  and  5   , the tool fitting  4  or a front portion of the power tool  1  according to a first embodiment is shown in an assembled state. For this purpose, the first locking element  14  is positioned into the first radial opening  17   a  of the basic body  12 , and the second locking element  15  is positioned into the second radial opening  17   b  of the basic body  12 . As will be described in detail below, the two locking elements  14 ,  15  can each here be positioned in a locking position or in a release position. 
     The locking ring  13  is positioned over the basic body  12  and is arranged in direction B behind the locking elements  14 ,  15 . As can be seen in  FIG.  2   , the inner lateral surface  13   a  of the locking ring  13  according to the first embodiment is designed to be step-shaped, with the result that it corresponds to the step-shaped upper end  19   c  of the locking elements  14 ,  15 . In other words: the upper end  19   c  of the locking elements  14 ,  15  matches, in its configuration, the inner lateral surface  13   a  of the locking ring  13 . 
     Furthermore, the press-on element  16  is also positioned over the basic body  12 . The press-on element  16  is here arranged in direction B in front of the locking elements  14 ,  15 . As can be seen in  FIGS.  2  and  3   , the rear end  19   c  of the respective first and second locking elements  14 ,  15  lies in the cutouts  24   a,    24   b  of the press-on element  16 . As can likewise be seen in  FIGS.  2  and  3   , a helical spring  29  is positioned in direction B behind the press-on element  16 . The helical spring  29  can also be referred to as a spring or spring element. The helical spring  29  presses, in direction B, onto the press-on element  16 . As a result, the press-on element  16  is pressed onto the locking elements  14 ,  15 . 
     The actuating cap  11  according to the first embodiment is likewise arranged over the basic body  12 . As shown in  FIG.  2   , the actuating cap  11  is of conical design and has a step  11   d  in the inner lateral surface  11   c,  cf.  FIG.  7   a   . The actuating cap  11  is positioned such that a front portion  11   a  of the actuating cap lies between the locking ring  13  and the press-on element  16 . The step  11   d  lies against the rear end  19   c  of the respective locking elements  14 ,  15 . 
       FIG.  2    shows the first and second locking elements  14 ,  15  in the locking position when the rear end  6   b  of the tool  6  designed as a chisel is to be held in the tool-fitting apparatus  4 . When the actuating cap  11  is pressed in direction A, the step  11   d  on the inner side  11   c  of the actuating cap  11  presses the first and second locking elements  14 ,  15  and the press-on element  16  against the spring force of the helical spring  29  in direction A. By virtue of the fact that the two openings  17   a,    17   b  on the basic body  12  are designed as oblong holes, the locking elements  14 ,  15  can be displaced in the axial direction A or B without the locking elements  14 ,  15  moving in the radial direction. When the locking elements  14 ,  15  are no longer in engagement with the locking ring  13 , the locking elements  14 ,  15  can finally move in the radial direction. When the two locking elements  14 ,  15  have moved in the radial direction, the two locking elements  14 ,  15  are no longer in the locking position, but in the release position. In the release position, the rear end  6   b  of the tool  6  designed as a chisel is no longer held in the tool-fitting apparatus  4  by the locking elements  14 ,  15 , and the tool  6  can be removed from the tool-fitting apparatus  4  in direction B. 
     In  FIGS.  10 ,  11 ,  12     a ,  12   b  and  12   c , the tool-fitting apparatus  4  or a front portion of the power tool  1  according to a second embodiment is shown in an assembled state. The tool-fitting apparatus  4  or the front portion of the power tool  1  according to the second embodiment substantially corresponds to the tool-fitting apparatus  4  or to the front portion of the power tool  1  according to the first embodiment. 
       FIGS.  10 ,  11  and  12     b  show the first and second locking elements  14 ,  15  in the locking position when the rear end  6   b  of the tool  6  designed as a chisel is to be held in the tool-fitting apparatus  4 . Here, both the first and the second locking elements  14 ,  15  are positioned in such a way that the flattened contact surface  21  at the front end  19   a  of the locking elements  14 ,  15  lies against the flattened plane on the inner lateral surface  13   a  of the locking ring  13 . The spring  29  presses the press-on element  16 , in direction B, onto the locking elements  14 ,  15  and thus the locking elements  14 ,  15  against the locking ring  13 . When the actuating cap  11  is pushed in direction A, the step  11   d  on the inner lateral surface  11   c  of the actuating cap  11  as a contact surface presses onto the press-on element  16  and presses the press-on element  16  against the spring force of the spring  29  in direction A. As can be seen in  FIG.  11   , the rear end  19   b  of the locking elements  14 ,  15  is positioned in the cutouts  24   a,    24   b  of the press-on element  16  (according to the second embodiment) in such a way that the lips  27  at the cutouts  24   a,    24   b  each engage in one of the depressions  22  on the left and right lateral surfaces of the locking elements  14 ,  15 . This creates a form-fitting connection between the press-on element  16  and the locking elements  14 ,  15 . Here, the material of the press-on element  16  is to be selected so that, on the one hand, the lips  27  are at least so flexible or movable that the rear end  19   b  of the locking elements  14 ,  15  can be brought past the lips  27  into the cutouts  24   a,    24   b  of the press-on element  16 . On the other hand, the material must be selected so that the lips  27  offer at least such resistance that the rear end  19   b  of the locking elements  14 ,  15  can be pulled only with a relatively high expenditure of force past the two lips  27  again and out of the cutouts  24   a,    24   b  of the press-on element  16 . When the press-on element  16  is pressed in direction A, the press-on element  16  can likewise pull the first and second locking elements  24   a,    24   b  in direction A. When the first and second locking elements  14 ,  15  move in direction A, the two locking elements  14 ,  15  are no longer in engagement with the locking ring  13 , with the result that the locking elements  14 ,  15  can move in the radial direction from the rear end  6   b  of the plugged-in tool  6 , cf.  FIG.  12   c   . When the two locking elements  14 ,  15  have moved in the radial direction, the two locking elements  14 ,  15  are located in the release position, with the result that the tool  6  can be removed from the tool-fitting apparatus  4 . 
     In  FIGS.  20 ,  21 ,  22 ,  24     a ,  24   b  and  24   c , the tool-fitting apparatus  4  or a front portion of the power tool  1  according to a third embodiment is shown in an assembled state. The tool-fitting apparatus  4  or the front portion of the power tool  1  according to the third embodiment corresponds substantially to the tool-fitting apparatus  4  or the front portion of the power tool  1  according to the second embodiment. The mode of operation to move the locking elements  14 ,  15  from the locking position into the release position is identical in both of the tool-fitting apparatuses  4  according to the second and third embodiments. 
     As already described above, the first and second locking elements  14 ,  15  according to the third embodiment have an elevation  23  at the rear end  19   b.  This elevation  23  serves to ensure an improved attachment or better form-fitting connection of the locking elements  14 ,  15  to the press-on element  16 . As can be seen in  FIGS.  20  and  21   , the upper or free end of the elevation  23  protrudes at the rear end  19   b  of the locking elements  14 ,  15  in the radial direction in the cutouts  24   a,    24   b  of the press-on element  16 . As a result, a larger proportion of the rear end  19   b  of the locking elements  14 ,  15  is located in the cutouts  24   a,    24   b  of the press-on element  16 , with the result that a correspondingly higher expenditure of force is necessary in order to pull the rear end  19   b  of the locking elements  14 ,  15  past the lips  27  and out of the cutouts  24   a,    24   b  of the press-on element  16 . The form-fitting connection between the locking elements  14 ,  15  and the press-on element  16  is thus improved.