Abstract:
A power tool has a power supply unit that can be removed on a device side for supplying electrical power, at least one indirectly actuatable switch for switching a drive machine on and off, a decoupling device for decoupling the switch, and a switching unit that actuates the switch at least indirectly.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   The invention described and claimed hereinbelow is also described in German Patent Application DE 10 360249.6 filed on Dec. 20, 2003. This German Patent Application, whose subject matter is incorporated here by reference, provides the basis for a claim of priority of invention under 35 U.S.C. 119(a)-(d). 
   BACKGROUND OF THE INVENTION 
   The present invention relates to a power tool. 
   Battery-operated power tools typically have a plug-in end for a rechargeable-battery block that contains electrical contacts and a locking system with mechanical lock-in. An electric switch actuated using a switching means is used to turn the power tool on and off. So that the switching means need not be permanently actuated during use, it can be locked in the “on” position, in which the switch is turned on. When the locking device is released, the switch automatically snaps back into the “off” position, in which the switch is turned off. When the rechargeable-battery block is replaced, it is possible for the switching means to accidentally remain locked in the “on” position and for the power tool to unintentionally start up when the charged rechargeable-battery block is attached. 
   SUMMARY OF THE INVENTION 
   The present invention is directed to a power tool with a removable power supply unit on the device side for supplying electrical power, with at least one indirectly operable switch for switching a drive machine on and off. 
   It is provided that a decoupling device for decoupling the switch and a switching means that actuates the switch at least indirectly are provided. The decoupling device, in particular, is configured and/or designed accordingly. Switches and switching means can be set or actuated independently of each other. 
   The decoupling device is preferably provided to forcibly turn off the switch when the power supply unit is removed and the switching means are locked in an “on” position, in which the switch can be switched on during normal operation. The decoupling device preferably includes at least one spring element. If the switching means are operatively connected with the spring element that causes the switch to turn on when the power supply unit is removed and the switching means are in the “on” position, simple and reliable handling is made possible. The normal operating state can be restored via a forcible release of the switching means from the “on” position. The power tool can be effectively prevented from accidentally starting up when the power supply unit is connected. The power supply unit is preferably a rechargeable-battery block or a battery block. The operational reliability of a power tool with a lockable switching means is increased. The present invention is particularly suited for power tools with which the switching means is lockable in the “on” position during operation. 
   An additional level of protection is achieved when at least one blocking means for blocking a coupling of the power supply unit when the switching means are in the “on” position and the switch is turned off. Maloperation is reliably prevented. The power supply unit cannot supply the switch with electric power as long as the blocking means are in the blocked position. The operator must first move the switching means into an “off” position before the power supply unit can be completely reinserted in the power tool and the switch can be turned on with the switching means. 
   If an actuating device is located between the switching means and the switch that includes at least a portion of the decoupling device, it can actuate the switch on a case-by-case basis or block attachment of the power supply unit without requiring any additional components. The system has a compact design and can be reliably operated. It is particularly advantageous when the actuating device includes at least one blocking means. Particularly safe handling is made possible. 
   If the power supply unit has a neck projecting at an angle that is operatively connected with the actuating device, it can be ensured—when the power supply unit is removed—that the actuating device can be disengaged from the switch. 
   If the actuating device according to a first and third exemplary embodiment has a multi-position flexible coupling, the spring element serving to rotate a first leg of the actuating device relative to a second leg that actuates the switch, the actuating device can be disengaged from the switch via rotation of the second leg. The actuating device can be detached from a pushbutton of the switch by rotating it while, when rotated in the reverse direction, the second leg impacts the pushbutton and is unable to engage with it until the switching element is moved into the “off” position and, to turn it on in normal operation, back to the “on” position. As an alternative, the actuating device is connected with a tension spring that disengages the actuating device and keeps it disengaged until the switching means are moved into the “off” position. To turn on the power tool, the switching means are moved back into the “on” position. 
   If the neck has a projection that is operatively connected with the actuating device, rotation of the actuating device can be easily enabled when the power supply unit is removed by the fact that, e.g., the projection slides over a lever and displaces it. 
   If, according to a second exemplary embodiment, the actuating device has a recess, the spring element being provided to disengage the recess from a switch lever of the switch, it can interact with a switch lever of the switch and turn the switch on and off. The actuating device blocks attachment of the power supply unit until the switching means are turned off and then back on again. 
   Further advantages result from the description of the drawing, below. Exemplary embodiments of the present invention are shown in the drawing. The drawing, the description and the claims contain numerous features in combination. One skilled in the art will also advantageously consider the features individually and combine them to form further reasonable combinations. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  Shows a section of a system according to the present invention according to a first exemplary embodiment with an actuating device with a multi-purpose flexible coupling, 
       FIG. 2  Shows a section of a system according to the present invention according to a second exemplary embodiment with an actuating device with a tension spring, 
       FIG. 3  Shows a section of a system according to the present invention according to a third exemplary embodiment with an actuating device with a multi-purpose flexible coupling and an angled end piece. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1  is a schematic illustration of a section of a power tool according to a first exemplary embodiment of the present invention. A power supply unit  32  designed as a rechargeable-battery block that is removable from the device side and is located in housing  10  serves to supply electric power to a not-shown electrical drive machine. Power supply unit  32  designed as a rechargeable-battery block has a neck  34  pointing toward a switch  14  and projecting at an angle, with electrical contact means  40 , e.g., sockets. Switch  14  is connected with corresponding electrical contact means  38 , e.g., plugs, which can be inserted in the sockets. 
   When power supply unit  32  is inserted, the drive machine is turned on and off using switch  14  in that an actuating device  20  designed as an adjusting slide presses against a pushbutton  18  of switch  14 . When pushbutton  18  is released, a compression spring  16  presses pushbutton  18  outward and automatically turns switch  14  off. 
   Actuating device  20  designed as an adjusting slide has a two-component configuration and includes a first leg  30  and a second leg  22 . First leg  30  is connected with second leg  22  via a multi-purpose flexible coupling  52  that has a spring element  24  configured as a compression spring. Multi-purpose flexible coupling  52  allows second leg  22  to rotate relative to first leg  30  around a longitudinal axis  54 . Multi-purpose flexible coupling  52  and spring element  24  form a decoupling device  58  with which a switching means  26  and switch  14  can be decoupled, so that switch  14  can be turned off, even though switching means  26  is locked in the “on” position. After a rotation action, spring element  24  designed as a torsion spring causes second leg  22  to return to its home position. The lower region of second leg  22  that latches behind pushbutton  18  has a surface  42  that is three-dimensionally inclined at an angle, by way of which second leg  22  rotates relative to first leg  30  as soon as a force acts in the switch-on direction indicated by an arrow and second leg  22  therefore does not bear against a corresponding surface of neck  34  of power supply unit  32 . 
   When power supply unit  32  is inserted, second leg  22  bears against neck  34  of power supply unit  32 , which blocks second leg  22  from rotating relative to first leg  30 . Actuating device  20  configured as an adjusting slide can be slid forward in the direction of the arrow using switching means  26  designed as a pushbutton. Via a driving feature  44  that engages in a recess  46  of actuating device  20 , actuating device  20  is driven and switch  14  is turned on via pushbutton  18 . To allow displacement, switching means  26  are guided in a recess  48  of a guide element  50 . Switching means  26  designed as a pushbutton can be locked in the “on” position by engaging a locking projection  28  in a corresponding recess  12  in the housing. 
   When power supply unit  32  is removed, second leg  22  of actuating device  20  pivots to the side due to the spring force of spring element  24  designed as a torsion spring and surface  42  at the end of second leg  22 , the surface being three-dimensionally inclined at an angle (upward in the figure). As a result, switch  14  turns off automatically by the fact that compression spring  16  presses pushbutton  18  outwardly. 
   Reattachment of power supply unit  32  is prevented by pivoted-away second leg  22  of actuating device  20  designed as an adjusting slide, surface  42  that is three-dimensionally inclined at an angle forming a blocking means  56  that prevents switch  14  from being energized and also blocks power supply unit  32  from being inserted. Power supply unit  32  cannot be reinserted and attached until switching means  26  has been moved from the “on” position into the “off” position. 
   To bring second leg  22  back into its home position and enable complete attachment of power supply unit  32 , switching means  26  designed as a pushbutton must be moved manually into the “off” position. With switching means  26  designed as a pushbutton in the “off” position, second leg  22  returns to its home position due to the spring force of spring element  24  designed as a torsion spring, and latches behind pushbutton  18  of switch  14 . In this position, power supply unit  32  can be inserted. When switched on, actuating device  20  designed as an adjusting slide bears against neck  34  of power supply unit  32 . 
     FIG. 2  is a schematic illustration of a section of a power tool according to a second exemplary embodiment of the present invention. A power supply unit  132  designed as a rechargeable-battery block that is removable from the device side and is located in housing  110  serves to supply electric power to a not-shown electrical drive machine. Power supply unit  132  designed as a rechargeable-battery block has a neck  134  that points toward a switch  114 , the neck having an angled surface  130  on its end face pointing toward switch  114 . Electrical contact means  140 , e.g., sockets, are located on power supply unit  132  configured as a rechargeable-battery block. Switch  114  is connected with corresponding electrical contact means  138 , e.g., plugs, which can be inserted in the sockets. 
   When power supply unit  132  is plugged in, the drive machine is turned on and off via switch  114  by the fact that an actuating device  120  designed as an adjusting slide—which is displaceable via an indentation  144  of a switching means  126  designed as a pushbutton—acts on a switch lever  118  of switch  114 . To displace switching means  126  designed as a pushbutton, it is guided in a recess  148  of a guide element  150  substantially parallel to housing  110 . A compression spring  116  automatically presses switch lever  118  into an “on” position (toward the right in the figure) as soon as switch lever  118  is not pressed into the “on” position (toward the left in the figure). During operation, switch  114  can be held in the “on” position by the fact that a locking projection  128  of switching means  126  designed as pushbutton latches in a recess  112  in housing  110 . Actuating device  120  designed as an adjusting slide has an indentation  144  into which a switch lever  122  engages. Actuating device  120  designed as an adjusting slide is connected with housing  110  in the vicinity of indentation  144  via a spring element  124  designed as a tension spring. Indentation  144  and spring element  124  form a decoupling device  158  with which switching means  126  and switch  114  can be decoupled, so that switch  114  can be turned off, even though switching means  126  are locked in the “on” position. 
   When power supply unit  132  is plugged in, actuating device  120  designed as an adjusting slide bears against neck  134  of power supply unit  132 , actuating device  120  designed as an adjusting slide resting against neck  134  so that actuating device  120  designed as an adjusting slide is oriented substantially parallel to housing  110 . As a result, switch lever  118  is moved into the “on” position. Switching means  126  designed as pushbutton can be locked in recess  112  by latching locking projection  128 . When the locking mechanism is released, compression spring  116  moves switch lever  118  into the “off” position, while the switch lever simultaneously pulls actuating device  120  designed as an adjusting slide and switching means  126  designed as a pushbutton into the “off” position (toward the right in the figure). 
   When power supply unit  132  is removed, spring element  124  designed as a tension spring pulls actuating device  120  designed as an adjusting slide downward in the direction of housing  110 , switch lever  118  disengaging and being tilted into the “off” position by compression spring  116 . Switching means  126  designed as pushbutton remain in the “on” position, however. Power supply unit  132  cannot be attached now, since its plug-in end is blocked by actuating device  120  designed as an adjusting slide. The end piece of actuating device  120  with an angled surface  142  forms a blocking means  156  that prevents switch  114  from being energized and also blocks insertion of power supply unit  132  provided actuating device  120  does not bear against neck  134 . Power supply unit  132  cannot be reinserted and attached until switching means  126  has been moved from the “on” position into the “off” position. 
   To attach power supply unit  132 , it is therefore necessary to insert switching means  126  designed originally as a pushbutton into a guide element  150  in the “off” position (toward the right in the figure), actuating device  120  being slid along with it via a driving feature  146 . Indentation  144  in actuating device  120  designed as an adjusting slide, and switch lever  118  become covered. If power supply unit  132  is now inserted, actuating device  120  designed as an adjusting slide is slid via corresponding inclined surfaces  130 ,  142  on neck  134  and on the end piece of actuating device  120  designed as an adjusting slide against the spring force of spring element  124  configured as a tension spring in the direction of switch  114 . Switch lever  118  engages in indentation  144 . Switch  114  can now be turned on with switching means  126  designed as a pushbutton. 
     FIG. 3  is a schematic illustration of a section of a power tool according to a third exemplary embodiment of the present invention. A power supply unit  232  designed as a rechargeable-battery block that is removable from the device side and is located in housing  210  serves to supply electric power to a not-shown electrical drive machine. Power supply unit  232  designed as a rechargeable-battery block has a neck  234  pointing toward a switch  214  and projecting at an angle, with a projection  236  pointing downward toward housing  210 . Furthermore, electrical contact means  240 , e.g., sockets, are provided. Switch  214  is connected with corresponding electrical contact means  238 , e.g., plugs, which can be inserted in the sockets. 
   When power supply unit  232  is inserted, the drive machine is turned on and off using switch  214  by the fact that an actuating device  220  designed as an adjusting slide presses against a pushbutton  218  of switch  214 . When pushbutton  218  is released, a compression spring  216  presses pushbutton  218  outward and automatically turns switch  214  off. 
   Actuating device  220  designed as an adjusting slide has a two-component configuration and includes a first leg  230  and a second leg  222 . First leg  230  is connected with second leg  222  via a multi-purpose flexible coupling  252  that has a spring element  224  configured as a compression spring. Multi-purpose flexible coupling  252  encloses, in the manner of a fork, spring element  224  designed as a torsion spring and allows second leg  222  to rotate relative to first leg  230  around a longitudinal axis  254 . Multi-purpose flexible coupling  252  and spring element  224  form a decoupling device  258  with which a switching means  226  and switch  214  can be decoupled, so that switch  214  can be turned off, even though switching means  226  is locked in the “on” position. Second leg  222  has two fingers  242 ,  244  arranged perpendicularly to each other and to longitudinal axis  254 , second finger  244  of which acts on pushbutton  218  and the other finger  242  interacting with projection  236  of power supply unit  232 . 
   Spring element  224  designed as a torsion spring retains second leg  222  of actuating device  220  designed as an adjusting slide in its home position in which it latches behind pushbutton  218  of switch  214 . In this position, switch  214  can be moved by switching means  226  configured as a pushbutton into the “on” position (toward the left in the figure), and it is locked in place via the latching of a locking projection  228  in recess  212 . When power supply unit  232  is inserted, first finger  242  in the figure is located below neck  234  between projection  236  and power supply unit  232 . 
   When power supply unit  232  is removed, projection  236  causes switch  214  to turn off immediately by the fact that second leg  222  of actuating device  220  designed as an adjusting slide rotates and is disengaged from pushbutton  218 . The spring force of compression spring  216  causes switch  214  to turn off. 
   When power supply unit  232  is inserted, projection  236  on neck  234  of power supply unit  232  displaces first finger  242  of second leg  222  of actuating device  220  designed as an adjusting slide and disengages pushbutton  218  from second finger  244  of second leg  222 . Second finger  244  forms a blocking means  256  that prevents switch  214  from being turned on and energized, since actuating device  220  must first be moved from the “on” position and into the “off” position before switch  214  can be re-actuated. 
   When power supply unit  232  is connected, first finger  242  is deflected against the spring force of spring element  224  as soon as projection  236  moves over finger  242 . As a result, actuating device  220  configured as an adjusting slide, and/or its second finger  244 , and pushbutton  218  disengage briefly, and pushbutton  218  jumps into the “off” position due to the spring force of compression spring  216  before contact means  240  of power supply unit  232  can come in contact with corresponding, device-side contact means  238 . When power supply unit  232  is inserted completely, projection  236  is no longer in contact with first finger  242 . Spring element  224  configured as a torsion spring brings about a return motion of second leg  222  and/or second finger  244  that is not complete, since second finger  244  now comes to rest against pushbutton  218  located in the “off” position and cannot latch behind it. 
   To turn on, switching means  226  configured as a pushbutton must first be moved into the “off” position. To this end, switching means  226  are slid in a recess  248  of a guide element  250 , actuating device  220  being displaced by a driving feature  246 . The spring force of spring element  224  designed as a torsion spring causes actuating device  220  designed as an adjusting slide to swivel completely back to its home position. In its home position, actuating device  220  designed as an adjusting slide latches behind pushbutton  218 , and the power tool can be turned on.