Abstract:
A holding device for hand machine tools, in particular a drill and/or a chipping hammer holding device, includes a hammer tube and at least one blocking body, which, when installed, connects the hammer tube to at least one additional holding component. The blocking body is provided with at least one blocking surface that is curved around at least one load tipping axis.

Description:
This application is a 35 U.S.C. §371 National Stage Application of PCT/EP2010/055880, filed Apr. 30, 2010, which claims the benefit of priority to Ser. No. DE 10 2009 027 316.6, filed Jun. 30, 2009 in Germany, the disclosures of which are incorporated herein by reference in their entirety. 
     BACKGROUND 
     The disclosure is based on a holding device for a portable power tool. 
     Rotary- and chisel-hammer holding devices are known which have a hammer tube and locking bodies which connect the hammer tube to a tool chuck in the fitted state. 
     SUMMARY 
     The disclosure is based on a holding device for a portable power tool, in particular a rotary- and/or chisel-hammer holding device, having a hammer tube and at least one locking body which connects the hammer tube to at least one further holding component in a fitted state. 
     It is proposed that the locking body have at least one locking surface curved about at least one load tilting axis. In this case, the expression “hammer tube” is intended to mean in particular an elongated, hollow component, in particular a hollow shaft, in which a striker of a percussion mechanism, a piston, in particular a skirt-type piston, and/or a percussion pin interacting with a striker is guided in the longitudinal extent of the hammer tube. The expression “load tilting axis” is intended to mean in particular an axis about which the locking body is tilted during a main load, such as, in particular, during a load on the hammer tube and/or on the holding component, to be connected to the hammer tube, in the axial direction of the hammer tube and/or in the circumferential direction of the hammer tube. Large load-bearing areas, small surface pressures, low wear and a long service life can be advantageously achieved by an appropriate configuration. 
     In this case, the locking surface can have various curvatures which seem appropriate to the person skilled in the art and can also be produced by various methods which seem appropriate to the person skilled in the art, e.g. by means of material removal processes, e.g. milling processes. In an especially advantageous manner, however, the locking surface is formed at least partly by a cambered surface, i.e. a surface produced by a plastic deformation operation, such as, in particular, by a rolling operation, as a result of which the service life can be further increased. The locking surface of the locking body can be designed in principle to be at least partly concave and/or, in an especially advantageous manner, to be at least partly and preferably completely convex. 
     Various components of the holding device for the portable power tool which seem appropriate to the person skilled in the art can be connected to the hammer tube by means of one or more corresponding locking bodies. However, if the holding device for the portable power tool has a tool holder having at least one holding surface which corresponds with the locking body in at least one operating state, an especially space-saving design, in particular without an additional holding flange, can be achieved. In this connection, the expression “tool holder” is intended to mean in particular a component which has an accommodating region for an application tool, such as in particular for a drill and/or chisel. 
     In a further configuration of the disclosure, it is proposed that the hammer tube and, in an especially advantageous manner, at least one further holding component have at least one curved holding surface which corresponds with the curved locking surface in at least one operating state, as a result of which surface pressure which occurs and wear which occurs can be further reduced. 
     The locking body can in principle have various shapes which seem appropriate to the person skilled in the art; for example, said locking body can be designed to be spherical, parallelepiped-shaped, bean-shaped, etc., and preferably correspondingly adapted mating surfaces should then be provided. In an especially advantageous manner, however, the locking body has, in the fitted state, a greater extent at least in the radial direction of the hammer tube than in the axial direction of the hammer tube, as a result of which advantageous overlapping can be achieved. 
     It is also proposed that the locking body have at least one curved end face and/or a curved lateral surface. In this case, the expression “end face” is intended to mean in particular a surface pointing in the longitudinal direction of the locking body, preferably in the radial direction of the hammer tube, and a “lateral surface” is intended to mean in particular a surface pointing transversely to a longitudinal direction and extending about a longitudinal axis of the locking body. Advantageous force flows and small surface pressures can be advantageously achieved by an appropriate configuration, specifically, in particular, if the locking body has at least two locking surfaces. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       Further advantages follow from the description of the drawings below. Exemplary embodiments of the disclosure are shown in the drawings. The drawings, the description and the claims contain numerous features in combination. The person skilled in the art will also expediently consider the features individually and combine them to form appropriate further combinations. 
       In the drawing: 
         FIG. 1  shows a schematic illustration of a rotary and chisel hammer with a partial section through a rotary- and chisel-hammer holding device, 
         FIG. 2  shows an enlarged illustration of a detail from  FIG. 1 , with play and tilt angle shown greatly exaggerated, 
         FIG. 3  shows an enlarged illustration of a detail of a first alternative, with play and tilt angle shown greatly exaggerated, 
         FIG. 4  shows an enlarged illustration of a detail of a second alternative, with play and tilt angle shown greatly exaggerated. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a schematically illustrated rotary and chisel hammer with a partial section through a rotary- and chisel-hammer holding device of the rotary and chisel hammer. The rotary- and chisel-hammer holding device comprises a hammer tube  10   a  in which a striker  36   a  of a percussion mechanism (not shown in any more detail) is guided. Furthermore, the rotary- and chisel-hammer holding device has three locking bodies  12   a  of the same kind which are uniformly distributed over the circumference of the hammer tube  10   a  and which, in a fitted state, connect the hammer tube  10   a  to a holding component for conjoint rotation and in an axially fixed manner, said holding component being formed by a tool holder  22   a . The tool holder  22   a  has an outside diameter which is smaller than an inside diameter of the hammer tube  10   a  and is inserted into the hammer tube  10   a.    
     The locking body  12   a  passes radially through a round aperture in the hammer tube  10   a , said aperture being defined by a holding surface  28   a . The locking body  12   a  has two locking surfaces  16   a ,  18   a  ( FIG. 2 ) which are convexly curved about its load tilting axis  14   a  and are formed by cambered surfaces. The locking body  12   a  is of cylinder-like design and has, in the fitted state, a greater extent in the radial direction  32   a  of the hammer tube  10   a  than in the axial direction  34   a  of the hammer tube  10   a . The locking surfaces  16   a ,  18   a  are formed by opposite end faces of the locking body  12   a.    
     In accordance with the number of locking bodies  12   a , the tool holder  22   a  has blind-hole recesses  38   a  on its inner circumference, specifically blind holes, the center axes of which extend radially relative to the hammer tube  10   a . The blind-hole recess  38   a  is defined in the radial direction by a holding surface  24   a  of the tool holder  22   a , said holding surface  24   a  corresponding with the locking body  12   a  in an operating state and being concavely curved about the load tilting axis  14   a . Furthermore, the rotary- and chisel-hammer holding device has, in the radially outer region of the hammer tube  10   a , a perforated ring  40   a , through which the locking body  12   a  passes in the radial direction. In the radially outer region of the perforated ring  40   a , the rotary- and chisel-hammer holding device has a holding component which is formed by a holding ring  42   a  and which has a concavely curved holding surface  30   a  on its side pointing radially inward, said holding surface  30   a  corresponding with the locking surface  16   a  of the locking body  12   a  in an operating state. The perforated ring  40   a  has a stepped outer contour and the holding ring  42   a  has a stepped inner contour. The inner contour and the outer contour are matched to one another, and the inner contour and the outer contour engage one inside the other in a positive-locking manner in the axial and radial directions. The perforated ring  40   a  and the holding ring  42   a  are secured in the axial direction  34   a  of the hammer tube  10   a  inside a portable power tool housing  46   a  by means of a clamping ring  44   a  and by means of a step  48   a  integrally formed on the portable power tool housing  46   a.    
     If, for example, a force F 1  loading the tool holder  22   a  in an axial direction away from the striker  36   a  occurs during operation, the locking body  12   a  is tilted about the load tilting axis  14   a  running perpendicularly to the axial direction  34   a  of the hammer tube  10   a  by the force F 1  and a reaction force F 2  opposed to the force F 1 , as shown exaggerated in  FIG. 2  for illustration. As a result of the curved locking surfaces  16   a ,  18   a  and the curved holding surfaces  24   a ,  30   a , large contact areas, small surface pressures and low wear are advantageously achieved. 
       FIGS. 3 and 4  show details of alternative exemplary embodiments. Components, features and functions that remain the same are basically marked with the same reference numerals. To distinguish between the exemplary embodiments, the letters a to c are added to the reference numerals. The description below is basically restricted to the differences from the exemplary embodiment in  FIGS. 1 and 2 . With regard to features and functions that remain the same, reference may be made to the description of the exemplary embodiment in  FIGS. 1 and 2 . 
       FIG. 3  shows a detail of an alternative rotary- and chisel-hammer holding device having barrel-shaped locking bodies  12   b  which connect together a hammer tube  10   b  and a tool holder  22   b  of the rotary- and chisel-hammer holding device for conjoint rotation and in an axially fixed manner. The locking body  12   b  has a curved locking surface  20   b , specifically a convexly curved lateral surface, and flat end faces  16   b ,  18   b . For each locking body  12   b , the hammer tube  10   b  has a radial through-aperture which is defined by a holding surface  28   b  of the hammer tube  10   b , said holding surface  28   b  being concavely curved about a load tilting axis  14   b  and corresponding with the locking surface  20   b  in an operating state. The holding surface  28   b  of the hammer tube  10   b  is a lateral surface or encloses the locking body  12   b  by 360°. Furthermore, the tool holder  22   b  has a radial blind-hole recess which is defined by a holding surface  26   b  concavely curved about the load tilting axis  14   b  and corresponding with the locking surface  20   b  during operation. The holding surface  26   b  is formed by a lateral surface or encloses the locking body  12   b  by 360°. Compared with the exemplary embodiment in  FIGS. 1 and 2 , the hammer tube  10   b  is radially defined in the region of the locking body  12   b  directly by a portable power tool housing  46   b . The hammer tube  10   b  is directly mounted in the portable power tool housing  46   b.    
       FIG. 4  shows a detail of an alternative rotary- and chisel-hammer holding device having barrel-shaped locking bodies  12   c  which connect together a hammer tube  10   c  and a tool holder  22   c  of the rotary- and chisel-hammer holding device for conjoint rotation and in an axially fixed manner. The locking body  12   c  has three curved locking surfaces  16   c ,  18   c ,  20   c , specifically a convexly curved lateral surface and two convexly curved end faces. For each locking body  12   c , the hammer tube  10   c  has a radial through-aperture which is defined by a holding surface  28   c  of the hammer tube  10   c , said holding surface  28   c  being concavely curved about a load tilting axis  14   c  and corresponding with the locking surface  20   c  in an operating state. Furthermore, the tool holder  22   c  has a radial blind-hole recess which is defined by a holding surface  26   c  concavely curved about the load tilting axis  14   c  and corresponding with the locking surface  20   c  during operation. The holding surface  26   c  is formed by a lateral surface or encloses the locking body  12   c  by 360°. The hammer tube  10   c  is radially defined in the region of the locking body  12   c  directly by a portable power tool housing  46   c . The curved end faces of the locking body  12   c  correspond with a concave holding surface  30   c  of the portable power tool housing  46   c  pointing radially inward and with a concave holding surface  24   c  of the tool holder  22   c  pointing radially outward.