Abstract:
The invention is based on a power hand tool, in particular a hammer drill and/or hammer chisel, with a percussion unit ( 10 ), which comprises a tumble bearing unit ( 12 ) with a tumble body ( 14 ) and also a piston ( 16 ). It is proposed that the power hand tool comprises at least two bearing locations ( 18, 20; 22, 24 ) arranged in parallel in the force of flux, by means of which the tumble body ( 14 ) is coupled to the piston ( 16 ).

Description:
CROSS-REFERENCE TO A RELATED APPLICATION 
     The invention described and claimed hereinbelow is also described in German Patent Application DE 10 2006 032 214.2 filed on Jul. 12, 2006. 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 hand-held power tool with a percussion unit. 
     Hand-held power tools—in particular rotary hammers and chisel hammers—that include a percussion unit and a wobble bearing unit with a wobble body and a piston are already known. The wobble body includes a wobble finger, which is coupled with the piston at a single bearing point. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a hand-held power tool, in particular a rotary hammer and/or chisel hammer, with a percussion unit that includes a wobble bearing unit with a wobble body and a piston. 
     It is provided that the hand-held power tool includes at least two and preferably at least three bearing points, which are connected in parallel in the power flow, via which the wobble body is coupled with the piston, and/or which are provided to transfer a drive motion from the wobble body to the piston. A “percussion unit” refers, in particular, to a unit that is provided to convert a rotary motion into a translatory percussion motion. A “wobble bearing unit” refers, in particular, to a unit with which, due to a wobble body supported obliquely in a bearing element, a wobbling motion of the wobble body results when the bearing element rotates. In addition, “connected in parallel in the power flow” refers, in particular, to a configuration in which a force to be transferred is distributed to the bearing points. Using a related inventive embodiment, various necessary compensation motions and/or drive forces that are produced may be advantageously distributed among several bearing points. The bearings that form the bearing points may be designed with thinner dimensions that a single bearing, and they may be integrated in a housing unit in a particularly flexible and space-saving manner. The wobble body may be coupled with the piston directly or, preferably, via intermediate components. 
     In particular, the overall length may be reduced when at least one bearing point is located next to the piston. If at least two bearing points are located next to the piston, it is also possible to realize an advantageous introduction of force that is at least largely symmetrical. “Next to” is understood to mean above the piston, below the piston, and, in particular, next to the piston, on the side. 
     In a further embodiment of the present invention it is provided that the wobble bearing unit includes a swivel body that is coupled with the wobble body. A “wobble body” refers, in particular, to a body that is supported such that it may swivel about a swivel axis, and that, in particular, may move relative to the wobble body. Using an appropriate design, it is possible, in particular, to advantageously distribute compensation motions among various bearing points. 
     The swivel body is preferably coupled with the piston via at least two bearing points and/or with the wobble body via two bearing points and, in fact, preferably via bearing points that are connected in parallel in the power flow, thereby making it possible to attain an advantageous transfer of force using bearings designed to be space-saving in size. The swivel body may be coupled with the piston and/or the wobble body directly or indirectly, via further components. 
     It is also provided that the swivel body includes at least one and preferably at least two arms that are moved at least partially laterally past the piston, and/or at least one and preferably at least two arms that are moved at least partially laterally past the wobble body, thereby advantageously utilizing lateral installation space and enabling overall length to be reduced. 
     When the wobble body includes at least two wobble fingers, bearing points that are located in parallel in the power flow may be realized using a simple design and in a space-saving manner, via which a drive force may be transferred from the wobble body to a further component, e.g., directly to the piston, or advantageously, to a swivel body. 
     Further advantages result from the description of the drawing, below. An exemplary embodiment of the present invention is 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 hand-held power tool, in a side view, 
         FIG. 2  shows individual parts of a percussion unit of the hand-held power tool in  FIG. 1 , in a side view, and 
         FIG. 3  shows the individual parts of the percussion unit in  FIG. 2 , in a front view. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  shows a side view of a hand-held power tool designed as a rotary hammer. The hand-held power tool includes a housing  40  and a percussion unit  10  located in housing  40 , percussion unit  10  including a wobble bearing unit  12  with a wobble body  14  and a piston  16 , which is guided in a translatory manner in a hammer tube  42  ( FIGS. 1 and 2 ). Wobble body  14  is supported obliquely on bearing means  46  via a roller bearing  44 , bearing means  46  being non-rotatably mounted on a shaft  50  that extends parallel to hammer tube  42  and/or percussion axis  48  ( FIGS. 2 and 3 ). Shaft  50  is coupled via a toothed gearing  52 —which is designed as a bevel gear—with a motor shaft  54  of an electric motor  56  of the hand-held power tool. Toothed gearing  52  includes a first bevel gear  58 , which is non-rotatably mounted on shaft  50 , and which meshes with a second bevel gear  62 , which is supported on one side via an axle  60 . Second bevel gear  62  meshes with a third bevel gear  64 , which is non-rotatably mounted on motor shaft  54 . The hand-held power tool has an L-shaped design, in which motor shaft  54  and its rotation axis, and percussion axis  48  form an angle  66  of 90°. The inventive means of attaining the object of the present invention may basically also be used in other designs that appear reasonable to one skilled in the art, e.g., particularly in designs in which a motor shaft is oriented parallel with a percussion axis. 
     According to the present invention, the hand-held power tool includes two bearing points  18 ,  20 ,  22 ,  24 , which are aligned in parallel in the power flow, and via which wobble body  14  is coupled with piston  16 . Wobble bearing unit  12  includes a swivel body  26 , which is coupled directly with wobble body  14 . Swivel body  26  includes two arms  32 ,  34 , which are moved laterally past wobble body  14 . Swivel body  26  is coupled on a side facing away from piston  16  with transverse segments  68 ,  70  via bearing point  18  with a first wobble finger  36  of wobble body  14 , which extends radially away from a main body of wobble body  14 . To ensure that installation and removal may be carried out in an advantageous manner, wobble finger  36  is connected via a screw connection  84  with a main body  86  of wobble body  14 , and it may be unscrewed from main body  86  of wobble body  14  for installation or removal. Basically, other components may also have a multi-part design, to ensure that installation and removal may be carried out in an advantageous manner. 
     On a side facing piston  16 , swivel body  26  with two further transverse segments  72 ,  74  is coupled via bearing point  20 —which is connected in parallel with bearing point  18  in the power flow—with a second wobble finger  38  of wobble body  14 , which is integrally formed with main body  86  of wobble body  14  and extends radially away therefrom. 
     Swivel body  26  also includes two arms  28 ,  30 , which are guided partially laterally past piston  16 , and via which swivel body  26  is coupled via bearing points  22 ,  24  located on the side next to piston  16  with a transverse bolt  76  that has been guided through piston  16 , and via transverse bolt  76  via a bearing point  78  with piston  16 . Bearing points  22 ,  24  are located in parallel in the power flow. As such, the drive force to be transferred to piston  16  during operation is distributed between bearing points  22 ,  24 . 
     Advantageously, transverse bolt  76  is located fixedly in piston  16 , and swivel body  26  is swivelably supported on transverse bolt  76  via bearing points  22 ,  24 . Basically, transverse bolt  76  could also be connected in piston  16  in a swivelable manner, and swivel body  26  could be fixedly connected with transverse bolt  76 . 
     During operation, shaft  50  is driven in a rotating manner using electric motor  56  via toothed gearing  52 , and bearing means  46  are driven in a rotating manner via shaft  50 . The rotary motion of bearing means  46  results in a wobble motion of wobble body  14 , which drives—via wobble fingers  36 ,  38 —swivel body  26  with a swivel motion around a swivel axis  80  that is concentric with transverse bolt  76 . The swivel motion of swivel body  26 , in turn, results in a translatory, back-and-forth motion of piston  16 . Swivel axis  80  always moves along percussion axis  48 . Wobble fingers  36 ,  38  are supported in bearing points  18 ,  20  such that they may move in their circumferential and longitudinal directions, so that, during operation, wobble fingers  36 ,  38  may swivel within bearing points  18 ,  20  around their longitudinal axes relative to swivel body  26 , and swivel body  26  may move in the longitudinal direction of wobble fingers  36 ,  38  relative to them, thereby also making it possible, in particular, to compensate for a height difference  82 .