Abstract:
A motor-driven machine tool includes a drive unit and a tool changing magazine with tool chambers that are placed into a transfer position adjacent to a tool receptacle to be loaded. The machine tool includes a tool changing device with a slide element that is arranged in operative connection with a tool. The slide element is moved by an operating element into a first position for accepting a tool from or transferring a tool to the tool chamber and into a second position to drive the tool. The slide element is fixed in the second position by a blocking element that is brought out of operative connection with the slide element by a transfer element to move the slide element from the second position to the first position. The slide element is arranged in indirect contact with the blocking element to move the blocking element by the transfer element.

Description:
This application is a 35 U.S.C. §371 National Stage Application of PCT/EP2012/067087, filed on Sep. 3, 2012, which claims the benefit of priority to Serial No. DE 10 2011 082 787.0, filed on Sep. 15, 2011 in Germany, the disclosures of which are incorporated herein by reference in their entirety. 
     BACKGROUND 
     The disclosure relates to a motor-powered power tool. 
     A power tool of this type is known from the applicant&#39;s DE 10 2006 059 688 A1. The known power tool has a tool change magazine having tool chambers for in each case one tool, which is arranged in a rotatable manner on an axis within the housing of the power tool, wherein the tool chambers are each adjustable into a position for transferring to a tool receptacle, to be equipped, of the power tool. A tool is transferred from a tool chamber into the tool receptacle and, respectively, from the tool receptacle back into a tool chamber by means of a slider element, which is formed for example in a magnetic manner on the side facing the tool. What is essential in this case is that the slider element, in the operating position of the power tool, in which the tool located in the tool receptacle is driven for example in order to screw in a screw, the tool can be supported on the slider element, and so the slider element forms a support for the tool. To this end, provision is made in the prior art for the slider element to be fixable by means of a locking mechanism. The locking mechanism is actuated by means of a separate operating element, which is distinct from the operating element for actuating the slider element. Thus, in order to initiate a tool change, it is necessary to actuate two operating elements, for which purpose an operator has to use both hands: with one hand, the securing mechanism of the slider element is deactivated via one operating element, while with the other hand, with the securing mechanism deactivated, the other operating element actuates the slider element and transfers the tool out of the tool receptacle into the corresponding tool chamber of the tool change magazine. 
     SUMMARY 
     Proceeding from the illustrated prior art, the disclosure is based on the problem of developing a motor-powered power tool such that a tool change is simplified to such an extent that only a single operating element is necessary in order to carry out a tool change. This has the advantage that an operator requires only one hand for a tool change, and so the other hand can be used for example very easily to support the power tool during the tool change. This problem is solved according to the disclosure, in the case of a power tool having the features of disclosure, in that the slider element is arranged in at least indirect contact with the blocking element in order to adjust the blocking element by means of the transmission element. In particular, the transmission element is operatively connected to the operating element in order to adjust from the second position into the first position. 
     The solution according to the disclosure has the advantage that only a single, manually actuable operating element is necessary for a tool change. By means of the one operating element, the power tool can be adjusted from the operating position (second position) into the non-operating position (first position). The single operating element has in this case a double function: firstly of adjusting the slider element from the second position into the first position, and secondly of taking the blocking element out of operative connection with the slider element (unlocking the blocking element). In particular, a separate operating element for unlocking the blocking element is not necessary. This makes it in particular possible to operate the power tool with one hand. 
     Advantageous developments of the power tool according to the disclosure are given in the dependent claims. All combinations of at least two features disclosed in the claims, the description and/or the figures are included in the scope of the disclosure. 
     In a preferred structural configuration of the disclosure, it is proposed that the blocking element has an end region facing the slider element, said end region bearing in the second position against the slider element, preferably against that end side of the slider element that faces the blocking element. 
     In order to allow the slider element to move in order to transfer a tool out of the tool receptacle, provision is furthermore made in the last-mentioned variant for, in order to adjust from the second position into the first position and vice versa, the blocking element to be arranged so as to be changeable in position, such that in the first position at least the end region of the blocking element is arranged in a plane below or above the slider element. 
     A configuration of the blocking element in which the latter has a pin-shaped region that serves for locking the slider element, and preferably is arranged in a pivotable manner on a pivot on the side opposite the end region, is very particularly preferred. 
     A particularly compact design of the power tool in the region of the tool change device is achieved when the pin-shaped region of the blocking element is oriented parallel to the slider element in the first position, such that the slider element is arranged alongside the pin-shaped region of the blocking element. 
     The actual adjustment of the blocking element is achieved in that the operating element is arranged in a longitudinally displaceable manner in a direction parallel to the drive axis of the tool receptacle and has a transmission element which interacts at least indirectly with the blocking element. 
     In order to effect a pivoting of the blocking element, provision is furthermore made for an end region, preferably remote from the slider element, of the transmission element to interact with a switching element arranged on the blocking element in order to adjust the blocking element, wherein the end region and/or the switching element have mutually facing contact surfaces that interact with one another and are arranged obliquely with respect to the drive axis of the tool receptacle and, when moving past one another, produce a force on the blocking element, said force effecting an adjustment of the blocking element from the second position into the first position. 
     In order to allow the slider element to move past the switching element so as to allow a design of the tool change device which is as compact as possible, it is furthermore proposed that the switching element is arranged in an approximately central region of the pin-shaped blocking element and has a cutout, preferably in the form of an aperture, through which the slider element is guidable as it moves between the two positions. 
     In order to effect a secure and defined position of the blocking element in the second position of the slider element, it is furthermore proposed that the blocking element interacts in operative connection with a restoring element preferably in the form of a compression spring, which subjects the blocking element to a force in order to move it in the direction of the first position. 
     In order to separate the movements of the operating element for adjusting the blocking element on the one hand and for adjusting the slider element on the other hand, it is furthermore proposed in a structurally preferred configuration that the operating element is arranged in a guide plate which has a longitudinal slot having two end stops, within which the operating element is movable into the second position along a displacement path in order to adjust the blocking element. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further advantages, features and details of the disclosure can be gathered from the following description of preferred exemplary embodiments and from the drawings, in which: 
         FIG. 1  shows a power tool according to the disclosure during its normal operation for driving a tool in a tool receptacle in a simplified longitudinal section, 
         FIG. 2  shows the power tool according to  FIG. 1  when a tool change is initiated, likewise in a simplified longitudinal section, and 
         FIG. 3  shows the power tool according to  FIGS. 1 and 2  in a position in which a tool can be removed from a tool change magazine and can be re-inserted into the latter, in a simplified longitudinal section. 
     
    
    
     DETAILED DESCRIPTION 
     Identical components or components having an identical function are provided with identical reference signs in the figures. 
       FIGS. 1 to 3  illustrate a power tool  10  according to the disclosure in the form of a battery-powered screwdriver. The power tool  10  configured as a portable power tool has a pistol-shaped basic form, in the housing  11  of which there is arranged a drive unit  12  for driving or rotating a tool  1  in a tool receptacle  15  having a longitudinal axis  13 . To this end, the drive unit  12  comprises a drive motor  16  in the form of an electric motor, which is powered preferably by means of a storage battery (not illustrated). The drive motor  16  is coupled, on the side facing the tool receptacle  15 , to a transmission  17 , the output shaft  18  of which drives an intermediate transmission  19 , which is coupled in turn to the tool receptacle  15 . 
     Arranged in the region of the output shaft  18  is a drum-shaped tool change magazine  20  that projects partially out of the underside of the housing  11  and on the periphery of which tool chambers  22  are arranged, preferably at equal angular intervals, in which in each case one tool  1  is received. The tool chambers  22  are formed in an open manner at their mutually opposite end sides, and the tool change magazine  20  is arranged so as to be rotatable about the rotation axis  23  of the output shaft  18 . In order to change a tool into or out of the tool receptacle  15 , the tool chambers  22  of the tool change magazine  20  are pivotable into a rotational position in which the relevant tool chamber  22  is aligned with the longitudinal axis  13  of the tool receptacle  15 . 
     A power tool described thus far is known from the applicant&#39;s DE 10 2006 059 688 A1, and so for further details on the design, reference is made to said application, which to this extent is intended to be part of the present application. 
     A tool  1  is transferred from a tool chamber  22  into the tool receptacle  15  and a tool  1  is returned from the tool receptacle  15  into the tool chamber  22  by means of a tool change device  25 . The tool change device  25  comprises a pin-shaped slider element  26 , of which the end region  27  that faces the tool  1  may be formed in particular in a magnetic manner, wherein the slider element  26  forms a support for the tool  1 , in the operating position illustrated in  FIG. 1 , in order for example to absorb axial screwing forces or pass them into the housing  11 . The slider element  26  aligned with the longitudinal axis  13  movable in the direction of the double arrow  28 . To this end, the slider element is coupled to an operating element  30  that is arranged on the top side of the housing and is graspable from the outside by an operator, wherein the operating element  30 , in the form of a control knob, is likewise movable in the direction of the double arrow  28 . 
     In the direction of the interior of the housing  11 , the operating element  30  has a pin-shaped extension  31  which penetrates through a longitudinal slot  32  in a guide plate  33 . The longitudinal slot  32  has, in parallel orientation with the longitudinal axis  13 , a front end stop  35  and a rear end stop  36 , as can be seen from joint consideration of  FIGS. 1 and 3 . On that side of the guide plate  33  that is opposite the operating element  30 , the extension  31  is connected to a, for example pin-shaped, transmission element  40  that acts as an adjusting element and is in turn coupled to the slider element  26  in particular by way of a form-fitting geometry, wherein play is formed between the transmission element  40  and the slider element  26  in the direction of the double arrow  28 . 
     The guide plate  33  is arranged in a displaceable manner, likewise in the direction of the double arrow  28 , in a guide  41  (not illustrated in more detail) of the housing  11 . The transmission element  40 , arranged directly under the guide plate  33 , has, on the side opposite the tool receptacle  15 , an end region  42  having an obliquely arranged edge  43  that forms a first contact surface. The end region  42  interacts with a pin-shaped switching element  45 . The switching element  45  is arranged in an approximately central portion of a pin-shaped blocking element  46  and is connected thereto. The switching element  45  has, on the side facing the end region  42 , a rounded dome  47  that forms a second contact surface. 
     In its end region remote from the tool receptacle  15 , the blocking element  46  is mounted in a pivotable manner on a pivot  48  in the housing  11 , wherein the pivot  48  is arranged for example axially behind the drive motor  16  and just above the latter. In the operating position, illustrated in  FIG. 1 , of the power tool  10 , the end region  49  opposite the pivot  48  forms, with its end face  50  facing the slider element  26 , an abutment or bearing surface for the slider element  26 . Furthermore, the switching element  45  has a cutout in the form of an aperture  51 , the cross section or the shape of which is matched to the cross section or the shape of the slider element  26  such that the slider element  26  can be guided through the aperture  51  in the transmission element  45 . 
     Arranged preferably on that side of the blocking element  46  that is opposite the switching element  45  is a restoring element in the form of a compression spring  52 , which subjects the blocking element  46  to a force in order to move it into a position in which the end side  50  of the blocking element  46  interacts with that side  53  of the slider element  26  that faces the blocking element  46 . 
       FIG. 1  illustrates the one position, the operating position of the power tool  10 , in which a tool  1 , for example a screw bit, can be rotated via the drive motor  16  and the tool receptacle  15 . In this position of the slider element  26 , the end side  50  thereof bears against the end side  53  of the slider element  26 , and so a pressure force, acting on the tool  1  in the one direction of the double arrow  28  in the direction of the housing  11 , is passed from the tool  1  to the slider element  26  and in turn from the latter, via the blocking element  46 , to the mounting of the blocking element  46  in the region of the pivot  48  and into the housing  11  of the power tool  10 . 
     In order to start a tool change, in accordance with  FIG. 2 , the operating element  30  is first of all moved in the direction of the arrow  54  along a displacement path A, which corresponds to the distance between the two end stops  35 ,  36 , this having the result that the transmission element  40  likewise moves in the direction of the arrow  54 , while the slider element  26  initially remains in its original position. As a result of the movement of the transmission element  40 , the switching element  45  of the blocking element  46  is pushed downward in the direction of the arrow  55  by the edge  43  of the transmission element  40  counter to the spring force of the compression spring  52 , such that the end side  50  of the blocking element  46  is taken out of contact with the end side  53  of the slider element  26 . In the end state in which the slider element  26  takes up its other (end) position, the blocking element  46  is arranged in a plane beneath the slider element  26 . In this state, it is possible to pull the slider element  26 , together with the corresponding tool  1 , out of the tool receptacle  15  and introduce it into the tool chamber  22 . This takes place in that the operating element  30  is moved in the direction of the arrow  56  in a manner corresponding to  FIG. 3 , with the result that both the transmission element  40  and the slider element  46  are moved away from the tool receptacle  15 . What is essential in this case is that, during the movement of the slider element  26 , the latter can be guided through the aperture  51  in the transmission element  45 . 
     In the position, illustrated in  FIG. 3 , of the slider element  26 , the tool  1  is arranged within its tool chamber  22 . In this position, the tool change magazine can be rotated by the operator by being rotated about the rotation axis  23 , in order to align a different tool  1  with the slider element  26 . As soon as this has taken place, the tool  1  can be transferred into the tool receptacle  15  by a corresponding movement of the operating element  30  counter to the direction of the arrow  56 . In this case, the blocking element  46  is moved by means of the compression spring  52  back into its position blocking the slider element  26 , as soon as, in accordance with  FIG. 1 , the end region  42  of the transmission element  40  has been moved past the switching element  45 . 
     The power tool  10  described thus far can be modified in many ways without departing from the scope of the disclosure. In particular, the use of the power tool  10  is not limited to a battery-powered screwdriver, and the configuration of the operating element  30 , of the blocking element  46  and of the transmission element  40  and the actuation of the latter via the actuating element  30  can be formed in a manner structurally different from the embodiment illustrated.