Patent Application
20090178243
This application is based on German Patent Application No. 10 2007 011 787.8 filed 12 Mar. 2007, upon which priority is claimed.
1. Field of the Invention
The invention relates to a handle, in particular an auxiliary handle, for a hand-guided power tool.
2. Description of the Prior Art
Numerous power tools such as angle grinders, drills, and rotary hammers are equipped with an auxiliary handle. In order to prevent vibrations generated during operation of the power tool from being transmitted to the operator, auxiliary handles are usually provided with vibration-damping means.
As described, for example, in DE 20 2004 012 400 U1, there are already known auxiliary handles in which an elastic intermediary element is provided as a vibration-damping means between a fastening part, which serves to mount the auxiliary handle onto the housing of a hand-guided power tool, and a grip region, which is designed to be grasped by the operator of the hand-guided power tool.
The present invention is based on a handle that includes a grip element and a fastening element for attaching the handle to a housing of a hand-guided power tool. So that vibrations during operation of the hand-guided power tool are not transmitted from the hand-guided power tool to the grip element of the handle or are only transmitted to a reduced degree, the grip element and the fastening element are spaced apart by at least one damping element Consequently the fastening element and the grip element do not touch each other directly, but only via at least one damping means.
In order to reduce vibrations in the handle as much as possible, according to the present invention, at least one of the two contact surfaces, i.e. the contact surface of the grip element or the contact surface of the fastening element, which are oriented toward each other via the damping element, is embodied as profiled so as to enlarge the contact surfaces. Preferably, both of the contact surfaces are profiled; the two contact surfaces can be profiled the same way or differently.
The expression “profiled contact surface” is understood to mean a contact surface that is not smooth in macroscopic terms, but instead has a certain roughness that is sufficient to significantly increase the surface area of the contact surface. In order to enlarge the contact surfaces of the grip element and fastening element, the contact surfaces are in particular provided with structural elements that result in a profiling or structuring of the contact surfaces. These structural elements can be grooves, ribs, beads, knobs, pins, teeth, or the like. These structural elements can be arranged regularly or irregularly.
The profiling of the contact surfaces produces an advantageous enlargement of the contact surfaces between the grip element and damping element and between the fastening element and damping element. It is therefore possible for the forces that occur to be favorably distributed over a large area, thus minimizing the danger of an overload of the damping element. In addition, due to its favorable material distribution, such an embodiment also experiences a high degree of vibration damping.
As structural elements, the contact surface of the grip element can be provided with claws and the contact surface of the fastening element can be provided with counterpart claws. The claws and counterpart claws reach between one another; they are situated spaced apart from one another and therefore do not directly touch. Between the claws and counterpart claws, a gap-shaped intermediate space is formed, into which the damping element, e.g. composed of an elastic material, is introduced. The claws and counterpart claws can be oriented axially in relation to the handle so that they reach between one another in an axial direction. The claws and counterpart claws can, however, also be oriented radially so that they reach between one another in a radial direction.
In another embodiment, the contact surfaces are profiled so that they engage with one another in a thread-shaped fashion. In this instance, structural elements in the form of grooves on the contact surfaces are embodied in a fashion similar to a thread. Thus, the contact surfaces of the grip element and fastening element are provided with a thread-like profile and the thread-like profiles of the two contact surfaces engage with one another like a thread and counterpart thread. The reciprocal engagement occurs in a contactless fashion since the contact surfaces are not permitted to touch one another directly, but rather only via a damping element. As the damping element, an elastic material, e.g. an elastomer, foam, or another vibration-absorbing material, can be injected in a thread-shaped form into the intermediate space between the grip element and fastening element.
Because of the profiling or structuring of the contact surfaces of the grip element and fastening element, the damping element is situated in a meandering or undulating form between the contact surfaces. It is particularly advantageous if the entire intermediate space between the contact surfaces is filled with a damping element. In addition to an elastomer or foam, the vibration-absorbing material for the damping element can also be provided in the form of a damping cushion filled with a fluid, e.g. a gas, a liquid, or a gel.
The grip element of the handle according to the present invention has an essentially cylindrical form. In a simple embodiment, it can be a cylinder. The cylindrical grip sleeve can also be adapted to the ergonomics of the human hand in that, by contrast with a purely cylindrical shape, it has varying diameters along its longitudinal axis, for example, and is thus bulbous or convex. The grip element here can be rotationally symmetrical so that the handle can be grasped at any orientation in relation to the operator. Alternatively, the grip element can also be especially adapted to the ergonomics of the human hand so that a first region of the grip element specifically serves as a support surface for the palm and a second region serves as a support surface for the fingers.
In addition, the grip element can be of a one-part or multipart embodiment. A multipart grip element is composed, for example, of a grip core and a grip casing, possibly with a damping element situated between them. One or more parts of the grip element can likewise be embodied as vibration-damping. Thus, for example, the grip casing can be composed of an elastic material, e.g. an elastomer or a foam, or the grip core can be embodied as an absorbing mass. The grip element can also have a coating composed of an elastic material.
The fastening element is used to detachably fasten the handle to a housing of a hand-guided power tool. In a simple embodiment, the fastening element can be a kind of threaded bolt that can be screwed into the housing of the hand-guided power tool. By contrast, the fastening element can be a kind of threaded nut or another type of recess with an internal thread, with the housing of the hand-guided power tool being provided with a corresponding thread for the attachment of the handle. In lieu of a screw connection device, the fastening element can also be provided, for example, in the form of a clamping device for attaching the handle to the housing of a hand-guided power tool.
The fastening element can be of a one-part or multipart embodiment. A two-part fastening element is composed, for example, of a fastening device and a support element; the fastening device can, for example, be a screw connection device, e.g. a threaded bolt, a screw, or the like, or can be a clamping device. The fastening device is supported on the support element, e.g. in that a threaded bolt is partially extrusion coated with plastic that constitutes the support element. The support element for the fastening device constitutes the head of the handle and is oriented toward the hand-guided power tool in the installed position of the handle on the housing of a tool. In such a two-part embodiment of the fastening element, the support element is situated spaced apart from the grip element and is connected to the grip element via a damping element.
The handle according to the present invention is particularly suited for use as an auxiliary handle for a cordless or corded hand-guided power toot such as an angle grinder or rotary hammer. Consequently, a hand-guided power tool that has a handle according to the present invention is also a subject of the present invention.
The invention will be better understood and further objects and advantages thereof will become more apparent from the ensuing detailed description of preferred embodiments taken in conjunction with the drawings, in which:
In a first embodiment schematically depicted in
According to the present invention, in the handle 100, the contact surfaces of the grip element 10 and fastening element 20 are embodied as profiled. To that end, claws 16 are formed onto the contact surface 15 of the grip element 10 and counterpart claws 26 are formed onto the contact surface 25 of the fastening element 20. As shown in
In both of the embodiments, the contact surfaces 15, 25 are significantly enlarged by the embodiment of claws 16, 17 and counterpart claws 26, 27.
In another embodiment of profiled contact surfaces 15, 25 shown in
As is clear from the drawings, due to the profiling or structuring of the contact surfaces 15, 25, the damping element 30 is situated in a meandering or undulating form between the contact surfaces 15, 25.
The foregoing relates to preferred exemplary embodiments of the invention, it being understood that other variants and embodiments thereof are possible within the spirit and scope of the invention, the latter being defined by the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2007 011 787.8 | Mar 2007 | DE | national |
