Patent Publication Number: US-7708260-B2

Title: Auxiliary handle device

Description:
CROSS-REFERENCE TO A RELATED APPLICATION 
   The invention described and claimed hereinbelow is also described in German Patent Application 10 2007 037 048.4 filed on Aug. 6, 2007. 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 is directed to an auxiliary handle device. 
   An auxiliary handle device for a hand-held power tool is already known, the auxiliary handle device including an auxiliary handle and a damping unit. The damping unit includes an absorber mass element that serves to dampen vibrations. 
   SUMMARY OF THE INVENTION 
   The present invention is directed to an auxiliary handle device, in particular for a hand-held power tool, with an auxiliary handle and a damping unit that includes at least one absorber mass element. 
   It is provided that the absorber mass element is designed in the shape of a sleeve along a main extension direction of the auxiliary handle. 
   In this context, an “auxiliary handle” is understood to be a region and/or a component and/or an element provided for placement—and enclosing, in particular—by one or two hands of an operator for guiding a hand-held power tool using an auxiliary handle device, and which is capable of being attached to the hand-held power tool in an auxiliary manner, adjacent to a further handle, in particular the main handle, the auxiliary handle device being located on the side of the hand-held power tool, and/or being capable of being removed from the hand-held power tool by an operator without the use of tools, and/or being located in a front region of the hand-held power tool close to the tool, and/or the auxiliary handle is designed in the shape of a rod. 
   An “absorber mass element” refers, in particular, to an element that is excited—at least within one intended frequency range of an initial oscillation and/or excitation oscillation—to generate a counter-oscillation that counteracts the initial or excitation oscillation, and therefore contributes to a reduction of vibrations. “Along a main extension direction of the auxiliary handle” is understood to mean an orientation and/or placement of the absorber mass element in particular, the length of the absorber mass element being oriented preferably parallel to the main extension direction and/or to a length of the auxiliary handle. The inventive design provides an advantageous damping of the auxiliary handle—of the gripping region in particular—and, therefore, a high level of operating comfort for an operator. In particular, vibrations may be advantageously damped along a preferred direction, e.g., along the main extension direction. The inventive auxiliary handle device is basically usable in conjunction with all hand-held power tools that appear reasonable to one skilled in the technical art, thereby making it easier, in particular, for an operator to guide hand-held power tools using the auxiliary handle. Due to its damping property, the auxiliary handle device is particularly advantageous when used with an angle grinder. 
   It is also provided that the auxiliary handle includes a grip sleeve that serves as a receiving area for receiving the absorber mass element, thereby providing a receiving function with a simple design and making it possible to locate the damping unit and/or the absorber mass element inside the auxiliary handle device in a particularly space-saving manner. 
   When the grip sleeve is supported in a radial and/or axial direction via the absorber mass element, an undesired and, in particular, direct transfer of vibrations from the hand-held power tool to the grip sleeve may be prevented. The grip sleeve is preferably located around the absorber mass element, thereby ensuring advantageous support of the grip sleeve in the radial and/or axial direction via the absorber mass element. 
   In a further embodiment of the present invention, it is provided that the damping unit includes at least one damping element that supports the absorber mass element in at least one direction, thereby making it possible to attain an advantageous, vibration-damping support of the absorber mass element along an axial and/or radial direction of the auxiliary handle. The axial direction is preferably oriented parallel with the main extension direction of the auxiliary handle, and the radial direction is oriented radially outwardly from an auxiliary handle axis that extends parallel with the main extension direction. 
   An advantageous support of the absorber mass element that enables a counter-oscillation to be generated may be attained when the damping element is a rolling element. The rolling element is preferably designed as a bearing, a ring, and/or further rolling elements that appear reasonable to one skilled in the technical art. 
   An advantageous support of the absorber mass element may also be attained when the damping element is made of an elastomer and/or a ring and/or a damping fluid. The elastomer preferably encloses a rubber-like, elastic material. The damping fluid is advantageously a pure fluid, a suspension, and/or further damping fluids that appear reasonable to one skilled in the technical art. 
   In an advantageous refinement of the present invention, it is provided that the damping unit includes at least one adjusting element that is provided for adjusting at least one damping parameter of the damping element. With this, the damping parameter may be advantageously adapted to an oscillatory behavior of the hand-held power tool. It is advantageously provided that the damping parameter is adjusted by an operator of the auxiliary handle device. 
   It is also provided that the damping unit includes at least a second sleeve-shaped absorber mass element, thereby ensuring that particularly effective damping of vibrations may be attained via the damping unit when the hand-held power tool and/or the auxiliary handle device are operated. 
   Particularly advantageous damping inside the auxiliary handle device that is adapted to a different oscillatory behavior, e.g., different oscillation frequencies in particular, may be attained when the different absorber mass elements have different damping properties. The absorber mass elements differ preferably in terms of the material, mass, volume or shape, and/or in terms of other properties that appear reasonable to one skilled in the art. The different properties of the individual absorber mass elements result in different damping properties. 
   A particularly compact damping unit with a particularly space-saving arrangement of the individual absorber mass elements may be advantageously attained when at least one of the sleeve-shaped absorber mass elements is located at least partially inside a further sleeve-shaped absorber mass element. The sleeve-shaped absorber mass element is preferably supported inside the further sleeve-shaped absorber mass element using a damping element, e.g., using an elastomer ring and/or further damping elements that appear reasonable to one skilled in the art. 
   It is also provided that at least one absorber mass element includes a segment-like projection in a radial direction, thereby making it possible to integrate an advantageous unbalanced mass for generating a counter-oscillation inside the damping unit. In this context, a “segment-like projection” refers, in particular, to a projection that preferably extends around a circular segment by a maximum of 180°, particularly advantageously by a maximum of 90°, and particularly preferably, it extends around a circular segment by a maximum of 45°, and/or is designed in the shape of a peg in particular. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows a hand-held power tool with an inventive auxiliary handle device, in a schematic depiction, 
       FIG. 2  shows the auxiliary handle device with an inventive damping unit, in a sectional view, 
       FIG. 3  shows the auxiliary handle device with an alternative damping unit that includes several absorber mass elements, in a sectional view, 
       FIG. 4  shows the auxiliary handle device with an alternative damping unit that includes a grip sleeve supported by absorber mass elements, in a sectional view, and 
       FIG. 5  shows the auxiliary handle device with an alternative damping unit that includes a segment-like unbalanced mass, in a sectional view. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   A hand-held power tool  12   a  designed as an angle grinder is shown in  FIG. 1 , in a perspective view from above. Angle grinder includes a housing  48   a  and a main handle  46   a  integrated in housing  48   a . Main handle  46   a  extends along a side  52   a  facing away from a tool  50   a  that is a cutting disk, in a longitudinal direction  54   a  of the angle grinder. An auxiliary handle device  10   a  is located in a front region  56   a  of the angle grinder that is close to the tool, and extends transversely to longitudinal direction  54   a  of the angle grinder. 
     FIG. 2  shows auxiliary handle device  10   a  with an auxiliary handle  14   a , a fastening unit  58   a , and a damping unit  16   a . Additional handle  14   a  includes a grip sleeve  26   a , which extends along a main extension direction  24   a  of auxiliary handle device  10   a . Grip sleeve  26   a  forms—together with a radially inwardly facing surface  60   a —a receiving area  28   a , which is provided to receive damping unit  16   a . Receiving area  28   a  is designed cylindrical in shape along main extension direction  24   a . Auxiliary handle  14   a  and/or grip sleeve  26   a  has a surface  62   a  that is curved radially outwardly along main extension direction  24   a  of auxiliary handle  14   a , thereby providing a particularly good grip for an operator of auxiliary handle device  10   a.    
   A ridge-type raised area is provided along main extension direction  24   a  in end regions  64   a ,  66   a  of auxiliary handle device  14   a , which limits a gripping region of grip sleeve  26   a  for an operator of auxiliary handle device  10   a  along main extension direction  24   a . The two ridge-type raised areas are located on auxiliary handle  14   a  in the manner of rings, in a circumferential direction  68   a , which extends perpendicularly to main extension direction  24   a . The two ridge-type raised areas extend radially outwardly from auxiliary handle  14   a . During operation of auxiliary handle device  10   a , ridge-type raised areas prevent the operator&#39;s hand from slipping when the operator guides hand-held power tool  12   a  using auxiliary handle device  10   a  and/or while force is being transmitted by the operator via auxiliary handle device  10   a  to hand-held power tool  12   a.    
   Fastening unit  58   a , which is designed to be screwed together with hand-held power tool  12   a , includes a bolt-shaped fastening element  70   a . A support element  72   a  abuts fastening unit  58   a  and extends in main extension direction  24   a  through end region  64   a  facing fastening unit  58   a  and through receiving area  28   a , and is fastened to end region  66   a  facing away from fastening unit  58   a . Support element  72   a  is designed as a single piece with fastening unit  58   a . Damping elements  74   a ,  76   a  made of an elastomer are located in a radial direction  30   a  between support element  72   a  and end regions  64   a ,  66   a . Damping elements  74   a ,  76   a  prevent a direct transfer of oscillations from support element  72   a  to end regions  64   a ,  66   a  and, therefore, to grip sleeve  26   a.    
   Damping unit  16   a  includes a sleeve-shaped absorber mass element  18   a , which is located inside receiving area  28   a  along main extension direction  24   a  of auxiliary handle device  14   a . Absorber mass element  18   a  is located around support element  72   a , in radial direction  30   a . To provide an additional vibration damping effect, further damping elements  36   a  are located along a path of vibration transmission from support element  72   a  in radial direction  30   a  outwardly to absorber mass element  18   a . Damping elements  36   a  are formed by rolling elements designed as elastomer balls. It is also basically feasible for damping elements  36   a  to be designed as elastomer rings and/or as further rolling elements that appear reasonable to one skilled in the technical art. 
   The elastomer balls bear against a radially outwardly oriented surface  78   a  of support element  72   a  and against a radially inwardly oriented surface  80   a  of absorber mass element  18   a . Absorber mass element  18   a  is thereby supported relative to support element  72   a  via the elastomer balls. Damping elements  36   a , i.e., the elastomer balls, dampen vibrations and/or absorb oscillation energy. The oscillation energy is at least partially absorbed and converted into internal friction energy of the elastomer balls and/or into external friction energy when the elastomer balls move relative to support element  72   a . Absorber mass element  18   a  abuts the elastomer balls outwardly in radial direction  30   a . Absorber mass element  18   a  is provided to generate a counter-oscillation and/or vibration that opposes an initial oscillation of hand-held power tool  12   a . Absorber mass element  18   a  is designed to absorb vibrations preferably in an axial direction  32   a ,  34   a , which is oriented parallel with main extension direction  24   a  of auxiliary handle  14   a . Absorber mass element  18   a  has a length  82   a  that is shorter than a length  84   a  of receiving area  28   a , thereby enabling counter-oscillations to be generated in axial direction  32   a ,  34   a  during operation of hand-held power tool  12   a.    
   Grip sleeve  26   a  abuts sleeve-shaped absorber mass element  18   a  outwardly in radial direction  30   a . Grip sleeve  26   a  is supported by absorber mass element  18   a  in radial direction  30   a  and is formed by an elastic coating around absorber mass element  18   a  applied via injection molding. The elastic coating is also located inside receiving area  28   a  between absorber mass element  18   a  and end regions  64   a ,  66   a . The elastic coating serves as damping element  38   a  and essentially prevents a direct transmission of vibrations from support element  72   a  and/or end regions  64   a ,  66   a  to grip sleeve  26   a  during operation of hand-held power tool  12   a  and/or auxiliary handle device  10   a . The elastic coating of receiving area  28   a  also forms a closed space, which may be filled with a damping fluid to further enhance a vibration-damping property of damping unit  16   a . To adjust a damping parameter of damping element  38   a  and/or to adjust a maximum counter-oscillation of absorber mass element  18   a , end region  66   a  facing away from fastening unit  58   a  is provided with a threaded adjusting element  42   a , which is screwed together with damping element  38   a . Length  84   a  of receiving area  28   a  may be adjusted using adjusting element  42   a . It is also feasible, however, for grip sleeve  26   a —together with absorber mass element  18   a —to be located at a distance from end regions  64   a ,  66   a , and for grip sleeve  26   a  to therefore be located such that it is decoupled from vibrations from end regions  64   a ,  66   a.    
   Alternative exemplary embodiments are shown in  FIGS. 3 through 5 . Components, features, and functions that are essentially the same are labeled with the same reference numerals. To distinguish the exemplary embodiments from each other, the reference numerals of the exemplary embodiments are appended with the letters a through d. The description below is essentially limited to the differences from the exemplary embodiment in  FIGS. 1 and 2 . With regard for the components, features, and functions that remain the same, reference is made to the description of the exemplary embodiment shown in  FIGS. 1 and 2 . 
     FIG. 3  shows an alternative auxiliary handle device  10   b  with a damping unit  16   b  that includes three sleeve-shaped absorber mass elements  18   b ,  20   b ,  22   b . The three absorber mass elements  18   b ,  20   b ,  22   b  are located inside a receiving area  28   b  of an auxiliary handle  14   b  of auxiliary handle device  10   b . Receiving area  28   b  is designed open in axial direction  34   b  at an end region  66   b  facing away from a fastening unit  58   b . Fastening unit  58   b  includes a fastening element  70   b , which is connected with an end region  64   b  facing fastening unit  58   b  via a form-fit, non-positive, and/or bonded connection. 
   The three absorber mass elements  18   b ,  20   b ,  22   b  differ in terms of their masses and diameters  88   b ,  90   b ,  92   b . The three absorber mass elements  18   b ,  20   b ,  22   b  may also differ in terms of a material and/or other properties that appear suitable to one skilled in the technical art. Absorber mass element  22   b  with the smallest diameter  88   b  is enclosed outwardly in a radial direction  30   b  by absorber mass element  20   b  with mid-range diameter  90   b . In turn, absorber mass element  20   b  is enclosed by absorber mass element  18   b  with greatest diameter  92   b . Damping elements  38   b ,  40   b  designed as elastomer rings are located between absorber mass elements  18   b ,  20   b ,  22   b  in radial direction  30   b  to support individual absorber mass elements  18   b ,  20   b ,  22   b  relative to each other. In order to provide equal support to absorber mass elements  18   b ,  20   b ,  22   b  along a main extension direction  24   b  of auxiliary handle  14   b , annular damping elements  36   b ,  38   b ,  40   b  are located between absorber mass elements  18   b ,  20   b ,  22   b , and between absorber mass element  18   b  and grip sleeve  26   b  in regions of receiving area  28   b  facing end regions  64   b ,  66   b.    
   In order to attach absorber mass elements  18   b ,  20   b ,  22   b  inside receiving area  28   b , damping elements  36   b ,  38   b ,  40   b  are integrally extruded with grip sleeve  26   b  and absorber mass elements  18   b ,  20   b ,  22   b . It is also basically feasible for damping elements  36   b ,  38   b ,  40   b  to be clamped between absorber mass elements  18   b ,  20   b ,  22   b  and/or between absorber mass element  18   b  and grip sleeve  26   b , thereby securing absorber mass elements  18   b ,  20   b ,  22   b  in axial direction  32   b ,  34   b  inside receiving area  28   b  using pressure-generated tension. It is also feasible for receiving area  28   b  to be closed to the outside at end region  66   b  facing away from fastening unit  58   b , and for absorber mass elements  18   b ,  20   b ,  22   b  to also be supported in a damping fluid. 
     FIG. 4  shows an alternative auxiliary handle device  10   c  with a damping unit  16   c  that includes two sleeve-shaped absorber mass elements  18   c ,  20   c . In contrast to the exemplary embodiment shown in  FIG. 3 , a fastening unit  58   c  is designed as a single piece with a support element  72   c  that extends through a receiving area  28   c  along a main extension direction  24   c  of an auxiliary handle  14   c . The two absorber mass elements  18   c ,  20   c  are located around support element  72   c , outwardly in a radial direction  30   c . Damping elements  36   c ,  38   c  designed as elastomer rings are located between absorber mass elements  18   c ,  20   c  and/or between absorber mass element  20   c  and support element  72   c . Damping elements  36   c ,  38   c  are applied to absorber mass elements  18   c ,  20   c  and/or support element  72   c  via injection molding. It is also basically feasible, however, for damping elements  36   c ,  38   c  to be clamped between absorber mass elements  18   c ,  20   c  and/or between absorber mass element  20   c  and support element  72   c . A grip sleeve  26   c  of auxiliary handle  14   c  is supported relative to absorber mass element  18   c  in radial direction  30   c  via integrally extruded damping elements  40   c  designed as elastomer rings. Grip sleeve  26   c  is separated from end regions  64   c ,  66   c  of auxiliary handle  14   c  along main extension direction  24   c , thereby ensuring that grip sleeve  26   c  is vibration-decoupled or vibration-damped relative to end regions  64   c ,  66   c  in axial direction  32   c ,  34   c.    
     FIG. 5  shows an alternative auxiliary handle device  10   d  with a damping unit  16   d  that includes a sleeve-shaped absorber mass element  18   d . As explained with reference to the designs shown in FIGS.  3  and  4 , a grip sleeve  26   d  is supported in a radial direction  30   d  relative to absorber mass element  18   d  via damping elements  40   d  designed as elastomer rings. Absorber mass element  18   d  is supported via damping elements  38   d  designed as elastomer rings relative to a support element  72   d , which is designed as a single piece with a fastening unit  58   d . A receiving area  28   d  of an auxiliary handle  14   d  is designed open toward an end region  64   d  facing fastening unit  58   d  and toward an end region  66   d  facing away from fastening unit  58   d , in the region of fastening unit  58   d , absorber mass element  18   d  extends in axial direction  32   d  beyond auxiliary handle  14   d.    
   In this region, absorber mass element  18   d  includes a peg-shaped, segment-like projection  44   d  that extends outwardly in radial direction  30   d . Segment-like projection  44   d  extends along a maximum angular range of 45° in a circumferential direction  68   d , and is provided to increase inertia and/or to produce an imbalance in order to absorb vibrations by generating a counter-oscillation. A fastening element  70   d  of fastening unit  58   d  includes a peg-shaped element  86   d  along axial direction  32   d ,  34   d  in the region of segment-like projection  44   d  of absorber mass element  18   d . Peg-shaped element  86   d  extends radially outwardly from fastening element  70   d  and is located on a side of fastening element  70   d  opposite to segment-like projection  44   d.    
   It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above. 
   While the invention has been illustrated and described as embodied in a auxiliary handle device, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention. 
   Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention.