Handheld power tool

A handheld power tool having a drive driving a motor shaft, which is accommodated in a power tool housing, in which at least one air inlet covered by a dust protection element is formed, and having a tool interface for connecting a tool. The dust protection element is pushed onto the power tool housing in an insertion direction and is secured on the power tool housing.

This nonprovisional application claims priority under 35 U.S.C. § 119(a) to German Patent Application No. 10 2018 113 730.3, which was filed in Germany on Jun. 8, 2018, and which is herein incorporated by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a handheld power tool, comprising a drive driving a motor shaft, which is accommodated in a power tool housing, in which at least one air inlet covered by a dust protection element is formed, as well as comprising a tool interface for connecting a tool.

Description of the Background Art

In handheld power tools, for example in angle grinders, the problem exists that chips are produced when processing material, which may damage the handheld power tool if they enter the interior thereof. This problem occurs, in particular, when processing metal, since the resulting particles and chips are electrical conductive, so that, if they enter the interior of the handheld power tool, there is the danger of short-circuits occurring, whereby under certain circumstances the handheld power tool itself is energized, which would be associated with a danger of electrical shock to the user. Dust protection elements are therefore often used, which cover the air inlet and with which a penetration of contaminants into the interior of the handheld power tool is to be avoided.

Handheld power tools of this type are known, for example, from DE 10 2008 009 227 A1. In these handheld power tools known from the prior art, the dust protection element, with which the interior of the handheld power tool is protected against the penetration of contaminants, in particular against the penetration of metal chips, is clipped onto the power tool from below. However, it has proven to be disadvantageous that the dust protector must be partially bent when it is clipped on, in order to clip it into the power tool housing. This type of attachment also gives rise to the problem that the dust protector is not securely attached to the power tool, since it may become loose and slide off the handheld power tool, in particular when vibrations occur.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to to reduce the aforementioned disadvantages and to provide an improved attachment of the dust protection element to the handheld power tool.

According to an exemplary embodiment of the invention, this object is achieved in a handheld power tool, in that the dust protection element is pushed onto the power tool housing along an insertion direction and is secured on the power tool housing.

In that the dust protection element only has to be pushed onto the power tool housing in the insertion direction, a particularly easy attachment is provided, which makes it possible to secure the dust protection element on the power tool housing without deforming it, which has a positive effect on the assembly complexity and longevity of the dust protection element. The insertion direction may be oriented essentially in parallel or essentially perpendicularly to the motor shaft. The wording, “essentially in parallel,” covers an angle range between the motor shaft and the insertion direction which is preferably between −35° and 35° and which is particularly preferably 0°. The wording, “essentially perpendicularly,” covers an angle range between the motor shaft and the insertion direction which is preferably between 55° and 125° and which is particularly preferably 90°. The insertion along the insertion direction may take place from the side facing away from the tool interface, i.e. from the back, or from the side facing the tool interface, i.e. from the front.

The power tool housing can have an at least two-part design and comprises a first housing part and a second housing part, the dust protection element being secured on the first housing part by the second housing part. This achieves the fact that the dust protection element pushed onto the first housing part is secured only by the second housing part, whereby, in particular, the axial position of the dust protection part is fixed in the assembled state of the handheld power tool and is unable to disengage from the handheld power tool, in particular even if vibrations occur.

The dust protection element can at least partially surround the power tool housing on the outside thereof and has a receiving section, with which a coupling section formed on the power tool housing interacts. Due to the use of the receiving section formed on the dust protection element, and due to the corresponding coupling section assigned to the power tool housing, the insertion direction is ultimately fixed, and a guidance for the dust protection element is formed, which represents a particularly simple way to push the dust protection element onto the power tool housing and secure it thereon.

The guidance may also be further simplified in that the receiving section can have an undercut. Due to this undercut, a rail is ultimately provided, which acts as a guide, so that, during assembly, an assembler only has to push the dust protection element onto the corresponding coupling section of the power tool housing with the aid of the undercut formed on the receiving section, whereby the assembly is further simplified. In this connection, it has also proven to be successful if the undercut has an L-shaped cross section. Due to the L-shaped cross section of the undercut, a guide is also provided perpendicularly to the insertion direction, which has a favorable effect on the positioning of the dust protection element on the power tool housing. Within the scope of the invention, it is also provided, in particular, that the coupling section and the receiving section are each provided multiple times, particularly preferably twice.

The seating of the dust protection element in the power tool housing may be further improved if at least one securing tab is formed on the dust protection element, which engages with at least one securing recess formed on the power tool housing for forming a latching connection. A stop is provided by the securing recess, which limits the pushing of the dust protection element onto the power tool housing along the insertion direction, whereby, in particular, the axial position of the dust protection element on the power tool housing is fixed. The latching connection is ultimately a securing component for the dust connection element on the power tool housing.

A tongue and groove joint can be formed between the first housing part and the second housing part and/or between the dust protection element and the second housing part. The use of the tongue and groove joint between the first housing part and the second housing part makes it possible to define the position thereof with respect to each other. In addition, a penetration of contaminants, such as electrically conductive particles or chips, into the interior of the power tool housing at the point of contact between the first housing part and the second housing part is effectively prevented thereby. Moreover, if a tongue and groove joint is also formed between the second housing part and the dust protection element, the position of the dust protection element, in particular, may be fixed thereby. The term, tongue and groove joint, explicitly also covers tongue in groove joints.

An insertion chamfer can be formed on the second housing part. When the second housing part is mounted on the first housing part, the dust protection element is moved hereby axially in the insertion direction with the aid of the insertion chamfer formed on the second housing part, whereby any clearance that may be present between the dust protection element and the first housing part is reduced.

To prevent the penetration of contaminants, such as metallic chips and particles, into the interior of the power tool housing, at least one screen structure can be assigned to the dust protection element, which at least partially overlaps the at least one air inlet when the dust protection element has been mounted. The screen structure may be designed as a single piece or comprise multiple sections. The screen structure may also be cast into the dust protection element or be otherwise fastened thereto, for example by gluing. In this connection, it has also proven to be successful if the screen structure has a mesh width between 0.100 mm and 0.500 mm and is, in particular, 0.250 mm. The selection of the mesh width makes it possible to control the particle size at which particles are able to enter the handheld power tool. The mesh width may thus be selected in such a way that particles which would negatively influence the functionality or the life span of the handheld power tool according to the invention are held back by the screen structure. However, if too small a mesh width of the screen structure is selected, this results in the fact that the through-flow of the handheld power tool by cooling air is not sufficiently ensured, which would also prove to be disadvantageous.

In particular, the assembly complexity may be further reduced by the fact that the first housing part and the second housing part are connected to each other by a screw connection. The screw connection makes it possible to particularly easily connect the two housing parts to each other, so that, in particular, a replacement of the dust protection element is possible, for example for cleaning purposes or for maintenance work.

DETAILED DESCRIPTION

FIG. 1shows an exploded representation of a handheld power tool1according to the invention, which, in the illustrated exemplary embodiment, is designed as an angle grinder. Handheld power tool1includes a drive2with a motor shaft3, which is accommodated in a motor housing24, which is part of a power tool housing4, in which at least one air inlet5is formed. Handheld power tool1also has a tool interface6, to which a tool7is attached, which, in the illustrated exemplary embodiment, is designed as a grinding wheel. In the area of the at least one air inlet5, a dust protection element8may be attached, which may be pushed onto power tool housing4in an insertion direction9oriented essentially in parallel to the longitudinal axis of motor shaft3, as is apparent, in particular, fromFIG. 2. Power tool housing4has a multi-part design and comprises motor housing24as well as a first housing part10and a second housing part11in the area of dust protection element8, which are connected to each other during assembly. The position, in particular the axial position, of dust protection element8relative to first housing part10is fixed by second housing part11, as is explained in greater detail below, in particular on the basis ofFIGS. 3 and 4. A latching connection is formed between dust protection element8and first housing part10by a securing tab21, which is assigned to dust protection element8and is apparent inFIG. 5, and a corresponding securing recess22, which is formed on first housing part10.

FIG. 2shows a side view of power tool housing4in the area of dust protection element8. In this figure, it is apparent, in particular, that dust protection element8has through-openings23, which are protected by a screen structure12and which at least partially cover the at least one air inlet5when dust protection element8is mounted. The mesh width of screen structure12is 0.250 mm.

FIG. 3shows a perspective view of section III-III of power tool housing4fromFIG. 2. It is apparent herefrom, in particular, that dust protection element8has a receiving section13, with which a coupling section14formed on first housing part10engages. Receiving section13of dust protection element8has an undercut15with an L-shaped cross section. In the illustrated exemplary embodiment, a tongue and groove joint is formed between dust protection element8and second housing11, including a groove16assigned to second housing11and a tongue17, which is formed on dust connection element8. As is also apparent from the sectional view inFIG. 3, dust protection element8is adapted to the outer shape of first housing part10, whereby dust protection element8may be easily pushed thereon. In the pushed-on state, dust protection element8then rests against the outer circumference of first housing part10over a wide area or at least in sections, and coupling sections14of first housing part10are accommodated in corresponding undercuts15of receiving sections13of dust protection element8. If second housing part11is now connected to first housing part10, tongue17engages with groove16, whereby the tongue and groove connection between second housing part11and dust protection element8is established, and dust protection element8is secured on power tool housing4.

As is apparent in the sectional view illustrated inFIG. 4along section IV-IV fromFIG. 2, a tongue and groove joint also exists between first housing part10and second housing part11. In the illustrated exemplary embodiment, assembly grooves19are formed in first housing part10, with which a securing tongue20assigned to second housing part11engages to form the tongue and groove joint between first housing part10and second housing part11. This tongue and groove joint additionally prevents dust protection element8from being displaceable axially against insertion direction9, since dust protection element8is fixed in its axial position by the tongue and groove joints. Insertion chamfers18are also used for this purpose, which are formed on second housing part11and are used to move dust protection element8axially in the direction of motor shaft3when second housing part11is mounted.

FIG. 5shows a perspective view of dust protection element8, including screen structure12situated therein, which has multiple sections, each having a mesh width of 0.250 mm in the illustrated exemplary embodiment. Moreover, securing tab21is apparent on dust protection element8on the end face facing away from drive2, which engages with securing recess22formed on first housing part10to form an axially operating latching connection in insertion direction9—with regard to motor shaft3—between dust protection element8and first housing part10.

The assembly of handheld power tool1is explained once again below, in particular the mounting of dust protection element8. Dust protection element8is first pushed axially onto first housing part10along insertion direction9, which is preferably oriented in parallel to motor shaft3. Coupling sections14, which are formed on first housing part10, engage with corresponding receiving sections13, which are formed on dust protection element8and which each have undercut15with an L-shaped cross section. Securing tab21of dust protection element8engages with securing recess22, which is formed on the outside of the end face of first housing part10facing away from drive2. A latching connection between dust protection element8and first housing part10is formed hereby. In another step, second housing part11is mounted on the unit form from first housing part10and dust protection element8perpendicularly to insertion direction9, a tongue and groove joint being formed between tongues17formed on dust protection element8and grooves16formed on second housing part11, on the one hand, as well as between securing tongues20formed on second housing part11and assembly grooves19assigned to first housing part10, on the other hand. Due to insertion chamfers18formed on second housing part11, an axial force is applied to dust protection element8in insertion direction9when second housing part11is mounted on the unit formed from first housing part10and dust protection element8, whereby any clearance that may be present between dust protection element8and first housing part10is eliminated but at least reduced.