BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of one embodiment of a handheld power tool of the invention, with a damping element;
FIG. 2 is a detail of an inside view into the housing of the handheld power tool of FIG. 1, with a first embodiment of a securing element;
FIG. 3 is a schematic view of a detail of a handheld power tool of the invention, with a further embodiment of a securing element;
FIG. 4 is a schematic view of a detail of a handheld power tool of the invention, with retaining elements;
FIG. 5 is a schematic view of a detail of a handheld power tool of the invention, with a further embodiment of a securing element; and
FIG. 6 is a schematic view of a detail of a handheld power tool of the invention, with a further embodiment of a securing element.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In FIG. 1, a right-angle power sander 10 is shown as an embodiment of a handheld power tool of the invention. The right-angle power sander 10 in the embodiment shown includes three housing parts: a first housing part 11 for receiving an electric motor (not shown), among other elements; a second housing part 12, which is embodied as a handle 15; and a third housing part 13 for receiving a gear (not shown), among other elements. A drive shaft drivable by an electric motor is coupled (not shown) to a driven shaft via a gear, comprising a driving gear wheel and a driven gear wheel. A sanding wheel is located on the driven shaft in a manner fixed against relative rotation (not shown). The electric motor is switched on and off by the user via an ON/OFF switch 19. In the embodiment shown in FIG. 1, the first housing part 11 and the second housing part 12 are of plastic, while the third housing part 13, which is the gearbox, is of metal.
In the region between the first housing part 11 or motor housing and the second housing part 12 or handle, the right-angle power sander 10 has a damping element 21 for vibration-decoupled or vibration-damped connection of the two housing parts 11, 12. As can be seen in FIG. 1 and particularly in the sectional view in FIG. 2, the first housing part 11 and the second housing part 12 are spaced apart from one another in the longitudinal direction of the right-angle power sander 10, so that an interstice 15 in the form of a gap between the first housing part 11 and the second housing part 12 is formed. The damping element 21 fills up the interstice 15, and the connection of the two housing parts 11, 12 to one another is effected solely via the damping element 21, so that there is no direct, rigid connection between the two housing parts 11, 12.
The damping element 21 comprises an elastic material, in particular a thermoplastic elastomer. It is connected to the first and second housing parts 11, 12 by injection molding, in which the damping element 21 is integrally molded from the inside onto the inner walls 14, 16 of the two housing parts 11, 12.
The damping element 21 is embodied approximately annularly, so that it extends all the way around in the interstice 15 between the two housing parts 11, 12. In the interstice 15, it has a radially outward-oriented bead 23. As can be seen in FIG. 2, to improve the damping properties the bead is embodied as essentially U-shaped.
In FIG. 2, a securing element 31 in the form of a metal plate is provided, which is placed in the two housing parts 11, 12 that are joined to a damping element 21 and is joined to them. The plate may be flat but is preferably curved, so that it is better adapted to the contour of the housing parts 11, 12. The securing element 31 is fixed in the housing part 12 embodied as a handle via a form lock. To that end, the securing element 31 is provided with openings 32. Pegs 17 that fit into the openings 32 are integrally molded onto the inner wall of the housing part 12 and optionally engage the openings from behind. In addition, the securing element 31 may be secured to the housing parts 11, 12 by adhesive bonding, welding, etc. In the first housing part 11, the connection between the securing element 31 and the housing part 11 has play. A round peg 18 is integrally molded onto the inner wall of the housing part 11, which fits with play into a round opening 33 in the securing element 31. In this embodiment, the securing element 31 is connected to the two housing parts 11, 12, but not to the damping element 21. The securing element 31 merely rests on the damping element 21, or has no contact whatever with the damping element 21.
Unlike what is shown in FIG. 2, instead of a separate component, the securing element may also be integrally molded (not shown) onto one of the two housing halves.
In FIG. 3, again unlike FIG. 2, the securing element 34 is connected not only to the two housing parts 11, 12 but also to the damping element 21, which here again comprises an elastic material, in particular an elastomer. Here the securing element 34 takes the form of struts, which may be embedded individually, or joined together, in the damping element 21. For integrally molding the damping element 21 onto the housing parts 11, 12, the securing element 34 can for instance be placed in the cavity of the injection mold and sheathed. The securing element 34 may also be attached to the housing parts 11, 12 additionally in a first step, for instance by means of adhesive bonding or sheathing. Only in a second step is the complete sheathing with the elastic material of the damping element 21 then done.
In another embodiment shown in FIG. 4, a damping element 21 of an elastic material is likewise provided in the interstice 15 between the first housing part 11 and the second housing part 12. For securely fastening the damping element 21 to the housing parts 11, 12, retaining elements 25 are built into the housing parts 11, 12. The retaining elements 25 may be of metal or plastic.
On the one hand, the retaining elements 25 are each connected to one of the housing parts 11 or 12. On the other, the retaining elements 25 are connected to the damping element 21. The damping element 21 may for instance be molded around the retaining elements 25, so that the retaining elements 25 are embedded in the damping element 21. In the embodiment shown in FIG. 4, the retaining elements 25 comprise a first part 25a, which is connected to one housing part, in this case the housing part 12, and an angled second part 25b, which is connected to the damping element 21.
In the embodiment of FIG. 5, the securing element 35, which if the damping element 21 should fail assures the connection of the housing parts 11, 12 to one another in the interstice 15 between the housing parts 11, 12, is at the same time a retaining element 25, which assumes the function described above in conjunction with FIG. 4. The securing element 35 is a plate, for instance of metal or plastic, which is embedded in the damping element 21 that comprises an elastic material, such as an elastomer.
In a further embodiment, the securing element 36 is embodied as a spring element, so that the securing element 36 additionally takes on the function of a damping element. The spring element takes the form of a leaf spring and is embodied in wavelike form. The securing element 36 is again embedded in the damping element 21 of elastic material. The securing element 36 is wider than the interstice 15 between the housing parts 11, 12, so that it can bring about an additional connection of the two housing parts 11, 12 to one another.
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 type described above.
While the invention has been illustrated and described as embodied in a handheld power tool, 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.
Patent Application
20080041603
