Patent Application
20100025062
The invention is based on a handheld power tool with a vibration-damped handle as generically defined by the preamble to claim 1.
Particularly in handheld power tools with a percussive drive, such as in drill hammers, chiseling hammers, and the like, relatively strong vibration occurs in the tool; it is transmitted to the handle of the tool and is not only unpleasant to the user but can even be harmful to health.
From German Patent Disclosure DE 101 36 015 A1, a handheld power tool is known, having a vibration-damped handle which has two legs, extending approximately parallel to the longitudinal direction of the handheld power tool, and is coupled resiliently to the tool housing. One lever, oriented essentially perpendicular to the longitudinal direction, is pivotably connected by one of its two ends to each of the two legs, and these levers are pivotably connected by their other ends to a tool housing joint region located between the two legs of the handle.
The invention is based on a handheld power tool with a vibration-damped handle, which handle has two legs, oriented in the longitudinal direction of the handheld power tool, and is coupled movably to the tool housing of the legs, and at least one lever, oriented transversely to the longitudinal direction, is pivotably connected to each of the two legs at an articulation point, and the levers are pivotably connected to a joint region located between the two legs of the handle. The term “extending in the longitudinal direction” should also be understood to mean orientations that form an angle with a longitudinal direction, preferably an angle of less than 30° and especially preferably less than 20°. Moreover, “oriented transversely to the longitudinal direction” should be understood in particular also to mean an orientation that forms an angle unequal to 90° with a longitudinal direction of the handheld power tool, such as preferably an angle between 110° and 70°, and especially preferably between 80° and 100°.
It is proposed that each lever, between the joint region and the respective articulation point, has a bearing point. This advantageously results in an improved practical implementation of vibration damping. The handle is given linear guidance, which is economical and low in friction. A very compact design is also achieved. Because the levers are each connected to the housing or to the handle by way of only one bearing point, the handle is very strongly decoupled from tool housing vibration. Furthermore, the handle with the lever construction gains quite high stability. By the incorporation of a resilient element, effective vibration damping is attained. The user is protected against harmful and/or annoying vibration. Moreover, handling of the handheld power tool is made easier. The handheld power tool is preferably an electric power tool, in particular a drill hammer, chiseling hammer, and the like.
In a coordinate aspect of the invention, the point of departure is a handheld power tool with a vibration-damped handle, which handle has two legs, oriented in the longitudinal direction of the handheld power tool, and is coupled movably to the tool housing of the legs, and at least one lever, oriented transversely to the longitudinal direction, is pivotably connected to each of the two legs at an articulation point, and the levers are pivotably connected to a joint region located between the two legs of the handle.
It is proposed that each lever, between the joint region and the respective articulation point, has a bearing point located on the handle end. Once again, a very compact design is advantageously obtained. Especially advantageously, the bearing point can be located inside the housing.
The levers may be braced with spring force on the handle. To that end, one, two, or more spring elements may be provided, which may be embodied either passively as conventional springs or actively in the form of suitable actuators. Expediently, it is provided that the levers are located inside the handle. This advantageously makes for a perceptible reduction in the amount of space required for the vibration damping.
In a favorable embodiment, the two levers may merge in one piece with one another. The joint region between the legs, in this embodiment, may be embodied as an elastic connection tongue. Expediently, at least one of the bearing points then makes a longitudinal compensation possible.
If the two legs of the handle, in the aforementioned joint region, are pivotably connected via a fork and a ball-like body that engages it, favorable movability of the lever connection is possible. For improved wear resistance, a sliding block may be located between the fork and the ball-like body; the ball-like body is pivotably secured to the sliding block and can slide in the fork when the ball-like body moves up and down.
It is advantageous if the handle can be braced on the housing by spring force. The handle is supported in such a way that it is extensively free of friction and it can execute a longitudinal motion in the direction of a primary vibration direction of a handheld power tool. A further advantageous embodiment for vibration damping of the handle is that one or more electrically controllable or regulatable actuators are located between the handle and the tool housing and damp vibration of the handle by counteracting a force or motion that occurs as a result of the vibration of the tool housing.
Further advantages will become apparent from the ensuing description of the drawings. In the drawings, exemplary embodiments of the invention are shown. The drawings, description, and claims include numerous characteristics in combination. One skilled in the art will expediently consider them individually as well and put them together to make useful further combinations.
Shown are:
Elements that remain essentially the same are identified throughout by the same reference numerals.
One lever 20, oriented transversely, in this case essentially perpendicular, to the longitudinal direction 48 of the handheld power tool is pivotably connected by one of its two ends to one leg 12 at a articulation point 16 and by its other end to a joint region 50 located between the legs 12 and 14 of the handle 10. Symmetrically to it, a lever 22 of the same kind is pivotably connected by one end to the other leg 14 at an articulation point 18 and is likewise pivotably connected by its other end in the joint region 50. The levers 20, 22 extend through openings, not identified by reference numeral, in the housing 28 to the articulation points 16 and 18 on the respective legs 12 and 14. In principle, however, an asymmetrical design is also conceivable, for instance with legs and/or levers of different lengths, so that in particular, a handle motion can be attained that deviates from a handle motion oriented in the longitudinal direction and can in particular be oriented to special vibration directions.
In the joint region 50, on the end of one lever 22, a fork 30 is embodied, which is engaged by one end, embodied as a ball-like body 32, of the other lever 20 and is retained movably therein, in particular in a height-adjustable and tiltable fashion.
Each leg 12 and 14, between the joint region 50 and the respective articulation point 16 and 18, has a respective bearing point 24 and 26 on the housing end, by way of which bearing point the respective lever 20, 22 is connected to the housing 28 and about which the respective levers 20 and 22 are pivotable. To that end, a pivot peg structurally connected to the housing engages a bore in the respective lever 20 and 22. To enable the necessary pivoting motion of the levers 20, 22, suitable recesses 52, 54 are provided as free spaces in the housing 28. In principle, a reverse disposition would also be conceivable.
The resilient coupling of the handle 10 to the housing 28 is attained by providing that the handle 10 is braced with its respective legs 12, 14 on the housing 28 via spring elements 34 and 36, preferably embodied as compression springs, that extend parallel to the longitudinal direction 48; the legs 12, 14 dip into corresponding channel-like guides, not identified by reference numeral, in the housing.
The spring elements 34, 36 keep the handle 10 in its rear position, remote from the tool (toward the right in the drawing). If manual force is exerted on the handle 10, the handle moves in the direction of the housing 28, until the manual force and the spring force of the spring elements 34, 36 balance one another. The handle 10 is thus insulated in terms of vibration from the housing 28.
As
A variant of the invention can be seen in
Two levers 20a, 22a, pivotably connected to legs 12, 14 of the handle 10, are embodied in one piece and are connected to one another via an elastic connection tongue 56 in the joint region 50. The two ends, toward one another, of the levers 20a, 22a are pivotably connected to the elastic joint of the connection tongue 56, which replaces the fork connection of the preceding embodiments. Once again, the respective bearing points 24a, 26a, as in the embodiment of
The end of the levers 20b, 22b remote from the fork or from the ball-like body 32 is pivotably connected to a peg 44 and 46, respectively.
For the motion of the levers 20b, 22b about the bearing points 24b, 26b, suitable articulations in the handle 10 are provided.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2006 016 442.3 | Apr 2006 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP07/51250 | 2/9/2007 | WO | 00 | 12/5/2007 |
