Hand tool comprising vibration damping elements

A hand tool having a tool spindle that can be driven rotatingly oscillatingly, with an outer housing having a gripping region, an inner housing that is at least partially arranged within the outer housing and coupled therewith, and further having a drive unit including a drive shaft that can be driven rotatingly. The drive unit is received within the inner housing. The drive shaft defines a drive axis. The outer and the inner housings are coupled with each other by a deformable damping element, which in the non-mounted state is formed plate-shaped. The damping element in a mounted state defines a peripheral section and an axial section. The peripheral section in the mounted state is configured for transmitting radial forces between the outer housing and the inner housing. The axial section in the mounted state is configured for transmitting axial forces between the outer housing and the inner housing.

BACKGROUND OF THE INVENTION

The invention relates to a hand tool, in particular a hand tool comprising a tool spindle that can be driven rotatingly oscillatingly, comprising an inner housing that at least partially is received within an outer housing and coupled therewith vibration muted, wherein in the inner housing there is received a drive unit comprising a drive spindle that can be driven rotatingly.

Such a hand tool is known from DE 10 2012 103 587 A1. The known hand tool comprises an outer housing extending substantially along a longitudinal axis and a drive unit received within the outer housing, wherein the drive unit is coupled to the outer housing by means of elastic power transmission elements.

In other words in the known hand tool the outer housing is vibrationally decoupled from the motor unit. Vibrations which e.g. are generated by the drive unit or by a tool unit coupled therewith are transmitted onto the outer housing only muted, if all. A user may grip the hand tool at its outer housing or may grip around it, respectively. Thus a vibration level sensed by the user can be reduced.

Hand tools may commonly also be designated as power-driven hand tools. The hand tools may comprise drive units, in particular electric drive motors. Hand tools usually can be designed as hand-guided or hand-held tools. Thus a user may grip a housing of the hand tool with one hand or with both hands to be able to guide the hand tool as desired, when in use. Hand tools with tool spindles that can be driven rotatingly oscillatingly usually are designated as oscillatory tools. Hand tools with a rotary oscillatory drive can be used for a plurality of sawing tasks, cutting tasks, scraping tasks, grinding tasks or similar work. Usually such hand tools have oscillating frequences in the range of about 10.000 to 25.000 oscillations per minute. The oscillations basically may be performed at a small pivot angle which for instance is between 0.5 degrees and 7 degrees.

However, it should be understood that hand tools basically may also be equipped with a rotary drive with constant direction of rotation part-time or full-time. However, such hand tools may be also be designed as angle grinders, hand saws or similar.

Lately the reduction of the vibration level sensed by the user has become more important. Thus for instance in commercial use there exist so-called maximum exposure doses which may limit the maximum operating time of a hand tool per day. At a given maximum exposure dose as well as a vibration level of a hand tool obtained by a computation or empirically, thus a maximum admissible operating time can be determined, in particular a daily operating time. Long-lasting high frequent vibrations may be detrimental to health. Although long-time effects usually do not occur, if a hand tool is only used occasionally, however, may become relevant when hand tools are used professionally or permanently.

The reduction of the vibration level is basically desirable. However an effective implementation comes with various challenges. At the one hand often a design of a hand tool that is vibrationally decoupled comes together with a weight increase—at least to a small degree. Basically this can be explained, since the housing of the hand tool is designed with an outer part and an inner part which are distant from each other by vibration-muting elements.

A further challenge may be the so-called guiding accuracy. Namely, if basically an inner housing is decoupled from an outer housing for damping vibrations, then on the other hand the user also can only operate by means of the soft vibration-damping elements of the inner housing and thus onto a tool received thereon. However, usually with hand-guided or hand-held hand tools feed forces are exerted by the user himself. Since with a vibrationally decoupled design there is no stiff connection between the outer part and the inner part of the housing, the forces exerted by the user may lead to respective deformations between the outer housing and the inner housing. This may in particular affect works that require a high accuracy and precision.

SUMMARY OF THE INVENTION

In view of this it is a first object of the invention to disclose a hand tool, in particular a hand tool comprising a tool spindle that can be driven rotatingly oscillatingly, that allows to be used with reduced vibration exposure.

It is a second object of the invention to disclose a hand tool that can be manufactured with little design effort and manufacturing effort.

It is a third object of the invention to disclose a hand tool that is be suitable also for long-time operations (permanent operation) having little vibrations.

It is a third object of the invention to disclose a hand tool having little vibrations and a long-life drive and preferably having a sufficiently compact design.

According to one aspect of the invention these and further objects are achieved by a hand tool comprising:

an outer housing having at least a gripping region; an inner housing being at least partially arranged within said outer housing and being coupled therewith vibration-muted;

a drive unit received within said inner housing including a drive shaft which can be driven rotatingly;

a tool spindle received within said inner housing;

a gear received within said inner housing coupled to said drive shaft and to said tool spindle for driving said tool spindle about a longitudinal axis thereof;

at least one deformable damping element coupling said outer housing and said inner housing, said damping element in a non-mounted state being substantially plate-shaped forming a peripheral section and an axial section;

wherein said peripheral section in said mounted state is generally configured for transmitting radial forces between said outer housing and said inner housing;

and wherein said axial section in said mounted state is generally configured for transmitting axial forces between said outer housing and said inner housing.

Namely, according to the invention there can be effected a vibrational decoupling between the outer housing and the inner housing at substantially low effort, using simply designed parts. The damping element or the damping elements in the non-mounted state may have a substantially flat design, such as in the shape of a prismatic plate. The non-mounted state of the damping element may correlate with a non-loaded, released position. The plate-shaped damping element now during the assembly of the hand tool may be deformed in a suitable way for providing the peripheral section and the axial section, whereby in a defined way radial and axial forces between the outer housing and the inner housing may be received and transmitted.

The damping element may also be designated as a plate element or a biasing element. The damping element usually is designed at least partially elastically. The damping element may be designed for example of elastic materials, rubber materials, thermoplastic elastomers or similar materials. The damping element at least partially may work vibrationally decoupling between the inner housing and the outer housing. The damping element commonly may also be designated as an anti-vibration element.

Since the damping element in the mounted state is configured for transmitting axial forces and radial forces between the outer housing and the inner housing, the damping element also may assist for securing an axial and a radial position between the inner housing and the outer housing.

According to various developments it is desired that the at least one damping element in the mounted or non-mounted state consists of the peripheral section and the axial section. This may include that in the mounted state a defined bending edge or folding edge may be present within the damping element, separating the peripheral and the axial section.

Since the at least one damping element is deformable at least partially, it may—starting from its simple, plate-shaped form in the non-mounted state—in the mounted state take relatively complicated contours and shapes. The at least one damping element may be manufactured and provided in a cost-effective way.

According to a further development of the hand tool the outer housing is assigned to a gripping side, wherein the inner housing with the drive unit is assigned to a drive side, and wherein the peripheral section and the axial section of the at least one damping element, preferably the peripheral sections and the axial sections of a plurality of damping elements, each define a peripheral distance and an axial distance between the outer housing and the inner housing.

The gripping side generally is the side of the hand tool which is gripped and held by the user. The drive side of the hand tool generally is the side at which the drive unit, the tool spindle and a tool received thereon are located. By the at least one damping element the gripping side can be decoupled from the drive side. Vibrations and vibration loads at the hand tool usually are generated at the drive side. The vibration-damping coupling between the gripping side and the drive side effects a damping of vibrations perceivable at the gripping side.

According to a preferred development the at least one damping element in the mounted state comprises an L-shaped cross section, in particular having at least substantially an L-shaped cross section, wherein a first leg of the cross section is defined by the peripheral section, and wherein a second leg is defined by the axial section. Apart from that depending on the design of the inner housing and the outer housings the damping element may substantially have a straight extension perpendicularly to the cross section. Is is also perceivable that the damping element in the mounted state comprises a bent extension perpendicularly to the L-shaped cross section. The damping element exemplarily may be configured as a rotationally sectioned body.

According to a further development a plurality of damping elements in the non-mounted state is arranged star-shaped, connected with each other, wherein in the mounted state at least a part of the axial section of each damping element is coupled with a common ring structure. Such a star-shaped design or connection, respectively, of the damping elements in the non-mounted state may also be configured plate-shaped. Exemplarily a closed or an open ring structure may be provided, from which the sections extend radially to the outside, which later in the mounted state form the peripheral section and possibly at least a part of the axial section. However, it is also perceivable that a plurality of damping elements are arranged in a sequence and coupled with a common web that connects the axial sections on the damping elements with each other.

A structure of a plurality of damping elements may have advantages from a manufacturing view. In particular the assembly of the hand tool may be simplified, since less separate parts must be assembled. The structure of the damping elements basically may be ring-shaped or row-shaped. Since the damping elements are deformable, the final shape may simply be generated by the assembly between the outer housing and the inner housing. The ring or web that connects the individual damping elements with each other, can also be used for sealing a radial gap between the inner housing and the outer housing. This may also be advantageous with respect to the coolant air guidance or with respect to the cooling of the drive unit, respectively.

According to a further development the outer housing comprises at least one support, in particular a receiving pocket, for the at least one damping element, wherein the support comprises at least one peripheral wall and a longitudinal stop, in particular an axial stop, wherein the peripheral section of the at least one damping elements in the mounted state contacts the peripheral wall, and wherein the axial section of the at least one damping element in the mounted state contacts the longitudinal stop. In this way at the outer housing, in particular at its inner contour, a defined receiving contour for the damping element or the damping elements can be provided.

According to a development of this design the at least one support comprises a first longitudinal stop and a second longitudinal stop which are arranged at an axial distance along the drive axis, wherein an axial distance L2between the first longitudinal stop and the second longitudinal stop is smaller than a length L1of an axial side of the damping element in the non-mounted plate-shaped state.

In other words the damping element may be designed so that in the non-mounted plate-shaped state it is simply too long for the receiving pocket, so that a section of the damping element, the axial section, is formed to the outside during joining of the inner housing with the outer housing. The axial section thus may be bent over or turned over.

However, basically it is also perceivable that the support or the receiving pocket, respectively, may have a length L2between the first longitudinal stop and the second longitudinal stop that is larger than the length L1of the axial side of the damping element (in the non-mounted, plate-shaped state). This may substantially simplify the assembly of the damping element. Also with this design in the mounted state there may form the peripheral section and the axial section of the damping element. To this end, in particular, the elasticity and the formability of the damping element coming therewith can be utilized.

Basically a substantially plate-shaped damping element in the mounted state may be contacted only sectionally in radial direction by means of the inner housing. In this way primarily the section being in contact with the inner housing is deformed, in particular compressed. This section may form the peripheral section. A residual section onto which no direct radial forces act, thus may undergo substantially less (radial) loads and deformations. This section may form the axial section. It is also perceivable that the compression at the peripheral section leads to an expansion at the axial section. In other words it is basically perceivable that the peripheral section in the mounted state is compressed (radially), and that the axial section in the mounted state is stretched (radially).

In a preferred development the at least one damping element in the mounted state is received at least partially with positive fit between the outer housing and the inner housing, wherein the axial section is substantially axially biased in a neutral position, and wherein the peripheral section in the neutral position is substantially radially biased. The neutral position may be a defined relative position between the inner housing and the outer housing which for instance is taken when by the user there is not exerted any feed force onto the hand tool. The at least partially form-fit support of the damping element assists to further decrease the manufacturing or assembly effort. If the position of the damping element is secured in a positive fit, then no separate fastening element at the outer housing or the inner housing are necessary, so that the effort for parts and joining can be reduced.

According to a further development the inner housing comprises a drive section and a spindle section, wherein the spindle section includes a tool spindle that can be coupled to the drive spindle by means of a gear unit, in particular an eccentric coupling mechanism, wherein the tool spindle at its end facing away from the inner housing comprises a tool receptacle for receiving a tool.

The gear unit may be used for transforming a rotary drive motion at the drive shaft into a rotatingly oscillating output motion at the tool spindle. Rotary oscillatory output motions commonly generate a particular vibration level so that with rotary oscillatory tools it is advantageous to couple the inner housing and the outer housing vibrationally muted.

According to the development of this design the inner housing further comprises a rear end facing away from the spindle section, wherein at least sectionally a peripheral face and a front face are formed, wherein the peripheral section of the at least one damping element, preferably a plurality of damping elements, in the mounted state contacts the peripheral face, and wherein the axial section of the at least one damping element, preferably of a plurality of damping elements, contacts the front face in the mounted state.

In this way the damping element may provide an axial stop as well as a peripheral stop for the inner housing within the outer housing. The inner housing may be inserted into the outer housing starting with its rear end, cartridge-like.

It should be understood that the front face of the inner housing must not necessarily be designed exactly perpendicular to the drive axis. Instead also a conical or a bent design or a different design is conceivable that includes at least one axial component. Also with a front face not extending ideally perpendicularly to the drive axis the axial position of the inner housing may be defined sufficiently precisely.

According to a further development of the hand tool the at least one damping element in the range of the rear end of the inner housing covers a peripheral gap between the inner housing and the outer housing at least partially. It is preferred, if the peripheral gap in the range of the rear end is axially sealed or covered, respectively. This design possibly may be combined with the ring structure or web structure mentioned above for connecting a plurality of damping elements.

Principally a peripheral gap between the inner housing and the outer housing is provided for allowing (small) relative movements therebetween. In this way the outer housing can be decoupled vibrationally from the inner housing. It should be understood that this may not necessarily be a complete decoupling. By contrast, the decoupling may include a vibration damping, with which still vibrations can be sensed at the outer housing, which however are considerably reduced when compared to the vibrations of the inner housing.

A coverage or a sealing of the peripheral gap may in particular be relevant for the air guidance or the coolant air guidance, respectively, within the hand tool. The inner housing usually comprises a drive unit, the operation of which includes a heat generation. It should be possible to lead away the heat efficiently. The coolant air guidance at a hand tool with an inner housing and an outer housing that are vibrationally coupled with each other comes with several challenges. In particular the coolant air to be discharged (warmed) must be guided through the inner housing as well as through the outer housing (at least partially), for leaving the hand tool. The masking or covering of the peripheral gap between the inner housing and the outer housing may assist a directed air guidance and thus a more effective heat diversion. This may affect the life-span of the drive unit and the hand tool.

According to a further development the hand tool comprises at least one deformable coupling element being configured as a further damping element which is coupled to the outer housing and to the inner housing, wherein the at least one deformable damping element and the at least one coupling element in the mounted state commonly define a neutral position of the inner housing within the outer housing, wherein the at least one damping element and the at least one coupling element in the neutral position are at least partially biased.

According to this design there may be first type of deformable damping elements as well as a second type of deformable damping elements, the coupling elements. The damping elements and the coupling elements may commonly be referred to under the term anti-vibration elements. The vibrational decoupling between the outer housing and the inner housing thus may not only be reached by the at least one damping element according to the above-mentioned designs.

According to another development of this design the hand tool comprises a first configuration of damping elements and a second configuration of coupling elements, wherein the first configuration and the second configuration are spaced from each other at least axially, and wherein in particular the second configuration is displaced from the first configuration along the drive axis into the direction of the spindle-side end of the outer housing.

Thus the first configuration may provide a coupling of the rear end of the inner housing with the outer housing. The second configuration may provide a coupling of the spindle-side section of the inner housing with the outer housing. Commonly there may result a plurality of coupling points between the inner housing and the outer housing which effect a defined relative position and a desired guiding stiffness between the inner housing and the outer housing. It should be noted in this context that it may be advantageous to design the coupling between the inner housing and the outer housing particularly soft and yieldable in the spatial directions which match substantially with the directions of vibrations caused at the inner housing. Vice versa it may be advantageous to design the coupling between the inner housing and the outer housing in the spatial directions sufficiently stiff that coincide with directions of common feed forces that are exerted by the user in operation.

According to a preferred development the first configuration comprises three or more damping elements that are aligned with each other axially and in particular are arranged distributed in a first peripheral region of the inner housing. The second configuration may comprise two coupling elements that are aligned axially with each other and in particular are arranged in a second peripheral region of the inner housing one opposite to the other. In particular the first configuration may comprise four damping elements that preferably are arranged substantially at equal angular intervals along the periphery of the inner housing. The two coupling elements of the second configuration commonly may define an axis along which they face each other. The common axis may be perpendicular to the drive axis and perpendicularly oriented to the spindle axis and may in particular intersect the drive axis.

According to a further development the outer housing comprises a rear end that faces away from the spindle-side end of the outer housing, wherein the rear end comprises a support contour for receiving an energy storage device, wherein the rear end comprises a section that is slanted with respect to the main direction of extension that preferably effects a radial displacement of the mass balance point of a received energy storage device in the direction of a side of the drive axis opposite the tool receptacle.

According to this configuration the energy storage device may be received at the gripping side, i.e. at the side of the hand tool that is vibrationally decoupled. This may be advantageous for the life-span of the energy storage device. The energy storage device may exemplarily be configured as an accumulator package. Hand tools, in particular oscillatory tools having a shaft-shaped housing at the rear end of which an energy storage device can be received, may require particular efforts for cooling air guidance. The rear end may be obstructed by the support contour for the energy storage device. Thus at this place coolant air can be sucked or exerted only to a limited extent or not at all. Thus it is advantageous to discharge major parts of the coolant air radially from the shaft-shaped outer housing. This may require that the coolant air radially flows through the inner housing as well as through the outer housing. Thus it may be advantageous to cover or to seal the peripheral gap between the inner housing and the outer housing axially in the direction of the rear end of the outer housing.

According to further development the drive unit comprises a compact motor that is received at the inner housing, wherein in addition at the inner housing there is received a fan unit which is assigned to the compact motor, wherein the compact motor is displaced axially from the fan unit into the direction of the spindle-side end, wherein the fan unit is arranged in particular between the compact motor and the support contour for receiving the energy storage device. Compact motors in particular are suitable for hand tools that can be battery-driven. Compact motors may have a small space requirement as well as a weight-optimized design.

Commonly compact motors have a high power density. Exemplarily compact motors may be designed so that the drive shaft is supported within an integral stator housing of the compact motor. In this way the effort for bearing the drive shaft can be limited. It is advantageous when the inner housing also serves as the stator housing for the compact motor. In total there may result an integral design of the inner housing with the drive unit comprising the compact motor. The fan unit may aspire or blow off coolant air through suitable air throughput openings within the inner housing and the outer housing. In particular, the air guidance of the hand tool may be designed so that the coolant air passes at least with one radial velocity component when passing the peripheral gap between the inner housing and the outer housing. A suitable coolant air path may be provided by the axial masking of the peripheral gap by means of at least one damping element.

According to a further development in addition at the outer housing there is received a control unit for controlling the drive unit which is displaced from the fan unit into the direction of the rear end of the outer housing and which in particular is arranged between the fan unit and the support contour for receiving the energy storage device. It is advantageous to support the control unit at the outer housing, since it is thus arranged at the vibrationally decoupled gripping side of the hand tool. This may be advantageous for the life-span of the control unit.

It is understood that the afore-mentioned features and the features to be explained hereinafter cannot only be used in the given combination but also in different combinations or independently, without departing from the scope of the current invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1shows a side view of a hand tool that is designated in total with10.FIG. 2shows a further side view of a hand tool that basically corresponds to the hand tool10according toFIG. 1.FIG. 1generally refers to components of the hand tool10that can be seen from the outside.FIG. 2shows a strongly simplified schematic sectional view for illustrating and explaining inner components of the hand tool10.

The hand tool10exemplarily is designed as an oscillatory tool. The hand tool10comprises an outer housing12as well as an inner housing14that is at least partially received within the outer housing12, see in particularFIG. 2. Basically the inner housing14may also be designated as a drive housing. The outer housing12and the inner housing14preferably have a relative distance to each other (in a non-loaded state). In other words it is preferred when at least in the non-loaded state there is no rigid connection or no tight contact, respectively, between the outer housing12and the inner housing14.

The inner housing14of the hand tool10comprises a drive section16and a spindle section18. The drive section16and the spindle section18of the inner housing14preferably are tightly connected with each other. Commonly the drive section16and the spindle section18may form a housing combination that is at least partially vibrationally decoupled from the outer housing12. In other words the inner housing14may be supported elastically at or within the outer housing12.

The outer housing12exemplarily may be designed shaft-shaped and comprises a gripping region20which may encompass major parts of the outer surface of the outer housing12. The gripping region20may be provided in a suitable way with contourings, profilings and similar form elements. The gripping region20is the region which a user of the hand tool10may generally grip with his hands, at least with one hand, and may guide it. It is preferred when the gripping region20allows for a plurality of gripping positions to allow a handling of the hand tool10in different orientations and for different applications. It is further preferred when the gripping region20allows for a gripping by a left-handed person as well as by a right-handed person.

In the spindle section18there is received a tool spindle22. The tool spindle22is configured for exerting rotary oscillations about the spindle axis24thereof, see also the double arrow designated with26. At its end facing away from spindle section18the tool spindle22comprises a tool receptacle28at which a tool30may be received. For securing and exchanging a tool30a tool clamping device may be provided (not shown inFIGS. 1 and 2). The tool clamping device exemplarily can be operated by means of a clamping lever32(FIG. 1) which is supported at the spindle section18of the inner housing14and which can be pivoted between a closed state and a released state.

The inner housing14is assigned to a drive side36of the hand tool10. The outer housing12is assigned to a gripping side34of the hand tool10, see alsoFIG. 2. It is preferred when the gripping side34is at least partially vibrationally decoupled from the drive side36. Oscillations or vibrations at the hand tool10usually are generated at the drive side36. If the gripping side34is sufficiently vibrationally decoupled from the drive side36, then only a lower vibration level acts onto the gripping side34. In other words vibrations felt at the gripping side34may be muted. On the one hand this may serve to improve working ergonomics. A user may be less impaired by the vibrations of the hand tool10and can longer hold and guide it. In addition the life-span of components of the hand tool10which are supported at the gripping side34may be extended, since smaller mechanical loads occur.

At the inner housing14a drive unit38is received comprising a motor40, seeFIG. 2. The motor40may in particular be designed as a compact motor. The inner housing14, or the drive section16of which, respectively, may at least partially serve as a housing for the motor40. The motor40is configured for driving a drive shaft42rotatingly about its drive axis44, see also an arrow designated with46. The drive shaft42may be supported at the drive section16of the housing14. In addition a fan unit48may assigned to the drive unit38that may be coupled exemplarily with the drive shaft42at a side facing away from the spindle section18of the motor40. The fan unit48may comprise at least a fan wheel which is configured for aspiring and/or blowing out coolant air. During operation of the hand tool10in particular in the region of the motor40heat may be generated. An effective cooling thus may affect the power capacity and the life-span of the hand tool10advantageously. Due to the “double casing” design of the hand tool10with the outer housing12and the inner housing14it may be required to guide or direct, respectively, coolant air through cavities within the inner housing14as well as through cavities within the outer housing12. This may for instance be affected through suitable passage openings for coolant air (not shown inFIG. 2).

In the hand tool10configured as an oscillatory tool the drive shaft42is coupled to the tool spindle22by means of an eccentric coupling mechanism50. For instance the eccentric coupling or eccentric coupling mechanism50may comprise an eccentric fork arranged at the spindle side that cooperates with a crowned bearing with an eccentric shoulder at the spindle-side end of the drive shaft42(not shown in more detail inFIG. 2). With respect to the design of the eccentric coupling mechanism50and a suitable design of the tool clamping device referral is made for instance to WO 2005/102605 A1.

The outer housing12at its end facing the tool spindle22comprises a support or a receiving contour54at which an energy storage device56may be supported, see alsoFIG. 1. The energy storage device56exemplarily may be released from the outer housing12, see also the dashed representation of the energy storage device56designated with56′ in the released state inFIG. 2. The energy storage device56may comprise at least one energy storage cell58,58′. The energy storage device56may in particular be an accumulator package.

In addition at the outer housing12—i.e. at the gripping side34—of the hand tool10exemplarily there is received a control unit60. In addition a switch62is received at the outer housing12. The control unit60and the switch62thus are received at the gripping side34that is vibrationally decoupled and thus is only subject to vibrational loads that are muted, at most. In this way the life-span of the control unit60and the switch62may be improved. The control unit60for instance may be configured for controlling the drive unit38and the fan unit48. To this end the control unit60may be coupled with the drive unit38, the switch62and the energy storage device56by means of suitable wires.

Referring toFIG. 2, as well as toFIGS. 3a, 3band 3cthe vibration-muting coupling of the inner housing14to the outer housing12is explained in more detail.FIGS. 3a, 3band 3cshow strongly schematically simplified representations of the inner housing14. It may in particular be the drive section16of the inner housing14, see alsoFIG. 2. For ease of illustration a more detailed representation of the spindle section18was dispensed with.

The inner housing14may be coupled with the outer housing12by means of several coupling elements or damping elements64,68. Elements for vibration-muting coupling of the inner housing14with the outer housing12generally may also be designated as anti-vibration elements. At the hand tool10different kinds of anti-vibration elements may be provided. It is also conceivable that the hand tool10is only equipped with one type of anti-vibration elements. According to the design shown inFIG. 2the inner housing14is coupled with the outer housing12by means of coupling elements64-1,64-2as well as by means of damping elements68-1,68-2,68-3and68-4(not shown inFIG. 2, see alsoFIG. 3c). The coupling elements64may be of one type. The damping elements68may be of a type different from the type of the coupling elements64. The representation of the coupling elements64and the damping elements68inFIG. 2is shown only schematically for representation.

The coupling elements64may form a configuration which is axially displaced from a configuration formed by the damping elements68. The configuration of the coupling elements64may be axially displaced from the configuration of the damping elements68into the direction of the spindle-side end of the inner housing14. The coupling elements64may be supported in a suitable way in the jointed or mounted state at supports66-1,66-2of the inner housing14(see.FIGS. 3a, 3band 3c) as well as at assigned counter contours within the outer housing12(not shown). It is preferred when at the inner housing14two supports66-1,66-2are supported for receiving two coupling elements64-1,64-2. The position of the coupling elements64-1,64-2inFIG. 2differs from the position of the supports66-1,66-2inFIGS. 3a, 3band 3c, for ease of representation. It is advantageous when the supports66-1,66-2define a common axis that is perpendicular to the drive axis44and perpendicular to the spindle axis24.

The configuration of the damping elements68may be received at a rear end of the inner housing14that faces away from the spindle-side end. It is preferred, when a plurality of damping elements68-1,68-2,68-3,68-4is arranged at a periphery of the inner housing14in the rear-end region thereof, see.FIGS. 3aand 3c.FIG. 4shows a representation of the (mounted) damping elements68without showing the inner housing14, in an orientation that is similar to the orientation according toFIG. 3c. It is preferred, when the four damping elements68are supported at a periphery of the inner housing14in a distributed way, in particular distributed at equal angular intervals.

At the inner housing14in addition there may be provided air passage openings52for coolant air (see.FIGS. 3band 3c), which may be assigned to a fan wheel of the fan unit48(seeFIG. 2). Coolant air may be blown out of the inner housing14or may sucked in, respectively, through the air passage openings52.

FIGS. 5aand 5bshow a possible configuration of the damping elements68.FIG. 5aillustrates a non-mounted state within which the damping element68is substantially non-loaded.FIG. 5bshows a mounted, assembled state within which the damping element68was brought into shape by means of the outer housing12and the inner housing14. It is preferred, when the damping element68in the non-mounted state has a generally plate-shaped or rectangular-shaped form76. For instance the damping element68in the non-mounted state may have the shape of a rectangular plate. In this way the damping element68may be manufactured at low cost and at high quantities. The damping element68in particular is made of a deformable material that is suitable for damping, at least in sections. These may be rubber materials, rubber-like materials, foamed materials, elastomeric materials, thermoplastic elastomeres or similar materials. It is preferred, when the damping element68acts damping, at least in sections. Thus the damping element68may attenuate occuring loads by inner friction and may decrease the energy load in a corresponding way.

The damping element68inFIG. 5b, in the mounted state, generally has a L-shaped cross section. It will be understood that the state exemplified byFIG. 5bgenerally only occurs in a deformed state. The damping element68in the mounted position comprises a peripheral section72and an axial section74which may form the legs of the L-shaped cross section. Between the peripheral section72and the axial section74there may be a transitional region which may in particular be rounded or bent, respectively. In the mounted state the peripheral section72may be mated to a length L2of a receiving pocket70(seeFIG. 2), which is smaller than the released length L1of the damping element68in the non-mounted state, seeFIG. 5a. In other words the damping element68may be designed “too long” for the receiving pocket70, so that during mounting an end section is bent or folded, respectively, and forms the axial section74.

Also the damping elements68exemplified byFIGS. 3a, 3band 3chave an L-shaped cross section that is generated by such a deformation. For ease of explanation the transition between the peripheral section72and the axial section74inFIGS. 3a, 3band 3cis shown rectangular. However it can be assumed that at least with some configurations a rounded transition similarly toFIG. 5bis generated.

The peripheral section72generated by the deformation of the damping element68may rest against a peripheral face80of the inner housing14, seeFIG. 3c. In the same way the axial section74formed by the deformation may rest against the front face82of the inner housing14. In this way the mounted damping elements68may define the position of the inner housing14relative the outer housing12axially and radially. The damping elements68may transmit radial and axial loads between the inner housing14and the outer housing12.

With reference toFIGS. 6aand 6ban alternative design of the damping elements68is explained. It may be advantageous to arrange the damping elements68-1,68-2,68-3,68-4star-shaped in the non-mounted state and to combine them by a common ring structure78. The design in the non-mounted state still may be flat or plate-shaped. In the mounted state, see.FIG. 6b, the ring structure78may form the axial section74or at least a part thereof. The ring structure78in the mounted state may cover or seal a peripheral gap between the inner housing14and the outer housing12. This may be advantageous with respect to the air guidance.

FIGS. 7a, 7bandFIGS. 8a, 8bshow different conceivable mounting situations of damping elements68which may e.g. be designed according toFIGS. 5band 6b. The orientation is depicted inFIGS. 7a, 7b, 8aand 8bwith an arrow each depicted with92that is directed to the tool spindle22, thus pointing “to the front”.

FIG. 7ashows a cross-section through the outer housing12and the inner housing14of a hand tool10. In the outer housing12there is formed a receiving pocket70for the damping element68. The receiving pocket70may provide a support length L2which is smaller than a length L1of the damping element68in the flat, non-loaded state, see alsoFIGS. 5aand 5b. In this way the damping element68may be deformed in the region of a longitudinal stop86of the receiving pocket70, to form the axial section74, see alsoFIG. 7b.

As mentioned above already it is also conceivable that the support length L2is lager than the length L1of the damping element68in a flat, non-loaded state. This may simplify the mounting of the damping element68. The outer housing12then can contact the damping element68along the total length L2of the receiving pocket70(radially). The inner housing14can contact the damping element68within an axial section (radially) which later forms the peripheral section72. Thus radial loads may in particular occur at the peripheral section72. This may lead to a deformation of the peripheral section72, such as to a decrease in the thickness of the peripheral section72. Also this load may effect an invasion or a thickness balancing, respectively, at the axial section74. The radial thickness of the axial section74may increase so that the axial section74due to this expansion may contact the front face82(see alsoFIG. 7b) of the inner housing14.

FIG. 7bshows a mounting situation that is comparable to the one ofFIG. 7a, wherein however only the outer housing12is shown sectioned. The receiving pocket70comprises a peripheral wall84, the longitudinal stop86as well as a further longitudinal stop88. The peripheral wall84in the mounted state is contacted by the peripheral section72. The peripheral section72extends between the first longitudinal stop86and the second longitudinal stop88. The axial section74of the damping element68rests agianst the first longitudinal stop86. In particular the first longitudinal stop86may be designed in the shape of a rib90. It is preferred, when the first longitudinal stop86starting from the outer housing12protrudes further radially to the inside into the direction of the drive axis44than the second longitudinal stop88. This may simplify the assembly of the damping elements68and the inner housing14.

The peripheral wall84and the peripheral face80include the peripheral section72between each other. The longitudinal stop86and the front face72include the axial section74between each other. If at the damping element68a ring structure78, seeFIGS. 6aand 6b, is formed, then a peripheral gap between the inner housing14and the outer housing12may be fully obstructed or covered, respectively. It will be understood that such an “obstruction” should not be completely stiff to not impair the damping effect of the damping elements68excessively. By contrast it may be advantageous, when only geometries are generated that avoid an exit or an insertion of coolant air in the rearward end region of the inner housing14into the peripheral gap between the inner housing14and the outer housing12. Also without a ring structure78the axial sections74may act obstructing and/or covering in their respective peripheral sections.

The design of the damping elements68and the receiving pockets70which is illustrated with reference toFIGS. 8aand 8bis basically similar to the design according toFIGS. 7aand 7b.FIG. 8ashows a lateral section through the outer housing12and the inner housing14.FIG. 8bshows an enlarged cross section of the representation according toFIG. 8in the region of a damping element68which is received at a receiving pocket70.

The peripheral section72is received between the first longitudinal stop86and the second longitudinal stop88in a known way. In addition the peripheral section72contacts the peripheral wall84of the receiving pocket70. Depending on which damping material the damping element68is made of, after the mounting of the inner housing14and the outer housing12there may form protrusions94,96at the damping element68which axially protrude beyond the length L2defined by the longitudinal stops86,88. The protrusion94is assigned to the axial section74or forms a substantial part of the axial section74, respectively. The protrusion96is assigned to the peripheral section72.

With the damping elements68an axial as well as a radial positioning between the inner housing14and the outer housing12may be performed at low manufacturing expenditure. In particular the damping elements68in the mounted state can provide a radial and an axial biasing force for the inner housing14. A coolant air flow between the inner housing14and the outer housing12, in particular within a peripheral gap between the inner housing14and the outer housing12, can be sufficiently sealed and guided. Such designs in particular are suitable for battery-operated hand tools10which are equipped with energy storage devices56at the rear side.