This application is a 35 U.S.C. §371 National Stage Application of PCT/EP2012/061309, filed on Jun. 14, 2012, which claims the benefit of priority to Serial No. DE 10 2011 078 376.8, filed on Jun. 30, 2011 in Germany, the disclosures of which are incorporated herein by reference in their entirety.
The disclosure relates to a handle device, in particular for a hand tool, preferably for a motor-driven hand tool. In this case, the expression “motor-driven” should be understood in particular to mean a drive of the hand tool having an electromotive, piezoelectric or electromagnetic drive principle, but also a drive by means of a fluid motor or combustion engine.
Handle devices comprising a grip unit and a fastening unit are already known, wherein a spring-elastic damping unit is arranged between the grip unit and the fastening unit. A grip unit is understood in this case to mean in particular a unit or an element which can be grasped, fixed or held by at least one hand of an operator in order to guide the hand tool. To this end, the grip unit has preferably a bar-like grip element. A fastening unit is understood to mean in particular a unit or device which is provided or designed to connect the grip unit to the hand tool, preferably releasably, wherein the term “connect” is understood to mean in particular to connect spatially in a substantially fixable manner with respect to the hand tool, in particular a housing of the hand tool. The damping unit is provided to transmit a vibration that occurs on the fastening unit in an operating state of the handle device or of the hand tool to the grip unit in an at least partially damped manner such that an operator is at least partially decoupled from the vibration.
Such a handle device is known for example from DE 100 29 536 A1, wherein the fastening unit comprises a fastening part and a threaded pin for connecting to a housing of a hand tool. In this case, the damping unit is manufactured from a more elastic material than the grip unit. Furthermore, the handle device in DE 100 29 536 A1 has at least one securing element which is intended to prevent the grip unit from detaching from the fastening unit, were the damping unit to be damaged or even destroyed for example in an overload situation or an overload state. Thus, as a result of overloads, for example damping units which comprise a rubber-elastic or elastomeric damping element can be permanently deformed, overextended or, as a result of extreme overstretching, torn.
Such overload states of the damping units occur inter alia in the event of impact loads on the hand tool or the handle device, in particular on the grip element, which are caused inter alia by the hand tool being dropped or falling.
It is an aim of the present disclosure to provide a handle device which has particularly high overload resistance. Ideally, the handle device according to the disclosure is in this case simultaneously cost-effective easy to produce.
This is achieved advantageously by the handle device having the features of the disclosure. According to the disclosure, provision is made to this end of an overload protection unit which, in the event of an overload state occurring on the grip unit or on the fastening unit, protects the damping unit from damage by at least a part of a force flux between the fastening unit and the grip unit being diverted, in the overload state, as a bypass to an additional force flux path. In this case, a force flux path is understood to mean in particular a spatial route of a force propagation, in particular over body structures of the handle device. A diversion of a part of a force flux to an additional force flux path should be understood in this case in particular to mean that a part of the force flux which is directed substantially entirely via a first body structure—in particular the damping unit—in a regular operating state is directed past the first body structure via a further body structure—in particular the overload protection unit—in a second state, primarily the overload state.
Preferably, the part of the diverted force flux makes up at least 25%, preferably at least 50% or particularly preferably at least 75% of the overall force flux which occurs and results in particular from the overload state.
The measures stated in the dependent claims produce advantageous developments and improvements of the features specified in the disclosure.
If the additional force flux path extends in a manner substantially parallel to a force flux path via the damping unit, the overload protection device can be configured advantageously in a compact manner.
A preferred embodiment of the handle device according to the disclosure is achieved when the grip unit comprises at least one main grip body, and preferably consists of the main grip body. As a result, in particular the number of components of the handle device is advantageously reduced. A main grip body is understood in this case to mean in particular a bar-like, in particular dimensionally stable grip body, preferably a cylindrical or hollow-cylindrical grip body. The main grip body is in this case manufactured in particular from a first material, preferably a thermoplastic or some other plastics material, in particular an injectable, castable or injection-moldable plastics material.
A further advantageous configuration is achieved when the fastening unit comprises at least one main body. A main body is understood in this case to mean a substantially dimensionally stable body which is designed in particular to absorb and/or transmit the force fluxes that occur between the grip unit and the hand tool, in particular a housing of the hand tool, in particular without itself being subjected to substantial elastic and/or plastic deformations compared with an unloaded state.
In an advantageously cost-effective and assembly-friendly embodiment, the damping unit of the handle device according to the disclosure is connected to the main grip body and/or main body. In a preferred configuration, the damping unit is in this case connected as one part to the main grip body and/or the main body.
In a further preferred configuration, at least two, preferably all three elements from the group consisting of the main grip body, the damping unit and the main body are manufactured from the first material.
A cost-effective configuration of the damping unit according to the disclosure is achieved when the latter comprises a defined number—preferably at least 4, 6 or particularly preferably 8—of bending elements which substantially enclose a grip axis of the grip unit in the circumferential direction of the grip axis. A bending element is understood in this case to mean an element which is deformable in a substantially elastic manner at least in one spatial direction compared with a rest position. Preferably, this spatial direction extends in a manner substantially perpendicular to the grip axis. Furthermore, the enclosure of the grip axis should be understood to mean in particular an arrangement which is circular, elliptical or polygonal, as seen in a cross section along the grip axis, and located substantially on a closed cross-sectional line. In a particularly preferred configuration, the bending elements are arranged in a manner directed substantially radially, in particular in a radiating manner away from the grip axis.
A particularly effective overload protection unit according to the disclosure has a hollow-cylinder-like support element which at least partially, preferably virtually entirely, surrounds the damping unit in the circumferential direction. A hollow-cylinder-like support element is understood in this case to mean in particular an element which is suitable for supporting the grip unit with respect to the fastening unit and in this case has a cross-sectional line which is circular, elliptical or polygonal, as seen along the grip axis, and is preferably substantially closed. However, it may also be advantageous for the support element to be constructed along the cross-sectional line from support segments which are interrupted with respect to the cross-sectional line.
In a preferred configuration, the overload protection unit, in particular the hollow-cylinder-like support element, is connected to the main grip body of the grip unit or to the main body of the fastening unit, and is preferably formed as one part therewith. Preferably, a support surface is provided on the in each case other body—the main body or the main grip body—said support surface being provided to come or be brought into contact in a force transmitting manner at least with a part of a contact surface which is provided on the support element.
In a preferred configuration, a contact spacing is provided between the contact surface and the support surface in a rest state of the handle device according to the disclosure. The contact spacing can in this case preferably be configured to be substantially constant over a circumference. However, it may also be advantageous for the contact spacing to be a function of a circumferential angle, in particular a circumferential angle with respect to the grip axis.
The contact spacing is in this case selected such that the contact surface cannot come into contact with the support surface in a regular operating state, even when the damping unit is acting in a vibration-damping manner, wherein the grip unit can be deflected from a rest position relative to the fastening unit. In particular as a result of this, the overall force flux between the fastening unit and the grip unit of the handle device according to the disclosure flows in an undivided manner via the damping unit and can be advantageously damped in a corresponding manner.
However, if an overload state occurs, the contact spacing can be reduced by a deflection of the grip unit relative to the fastening unit such that the support surface comes into supporting contact with the contact surface at least so as to be touching in a locally limited manner. Over the supporting contact surface which arises, an additional force flux path arises by way of example as an advantageous example of the disclosure, and a part of the overall force flux can now flow past the damping unit.
In an advantageous further development of the handle device according to the disclosure, at least one torsion inhibiting means is provided on the fastening unit and on the grip unit, said torsion inhibiting means limiting torsional moments acting on the damping unit to a maximum in the event of torsion of the grip unit relative to the fastening unit, in particular about the grip axis.
In a preferred embodiment, the torsion inhibiting means comprises at least one recess and at least one torsion blade engaging in the recess. In this case, the recess and the torsion blade are arranged in a manner mutually assigned to one another on the fastening unit and on the grip unit, preferably on the overload protection unit.
Further advantageous embodiments and developments can be gathered from the combination of the above-described features and the features of the exemplary embodiments described in the following text.
(An) exemplary embodiment(s) of the disclosure is/are illustrated in the drawings and explained in more detail in the following description. In the drawings:
Also arranged on the neck region 20 is a handle device 24 according to the disclosure. In this case, the handle device 24 is in the form of an auxiliary handle 26 of the hammer drill 10. In the example according to
The fastening unit 30 according to
The damping unit 32 has a first bearing surface 44 facing away from the grip unit 36. The main body 38 of the fastening unit 30 has a second bearing surface 46 which is provided in particular to support the first bearing surface 44 of the damping unit 32.
Arranged in a cavity 48 that extends through the grip unit 36 and the damping unit 32 along the grip axis 28 is a clamping nut 50. The clamping nut 50 is in this case received in the cavity 48 in a rotationally fixed manner about the grip axis 28. It is in this case placed preferably substantially beneath the first bearing surface 44 along the grip axis 28.
The first bearing surface 44 has a bore 52 which is provided in a substantially concentric manner with the grip axis 28, said bore 52 being arranged in a substantially coaxial manner with an internal thread 54 of the clamping nut 50.
The fastening unit 30 furthermore has a clamping space 56 which for its part a bore 58 for passing through a clamping screw 60 arranged in the clamping space 56 is provided in an end region facing the grip unit 36. The clamping screw 60 has external thread 62 matching the internal thread 54, such that the damping unit 32 is connectable to the fastening unit 30 by means of the clamping screw 60. In particular, by appropriately tightening the clamping screw 60 in the clamping nut 50, the first and second bearing surfaces 44, 46 come into contact with one another such that the damping unit 32 is supported on the fastening unit 30, thereby defining a rest position of the grip unit 36 relative to the second bearing surface 46. In the example according to
In the example according to
An end face 66, facing the fastening unit 30, of the hollow-cylindrical support element 64 is in this case configured according to
In the rest position, illustrated in
The eight bending beams 74, 76 stand, in the example according to
During operation of the hammer drill 10 according to
The contact spacing d of the contact surface 68 from the support surface 70 is in this case selected such that the two surfaces come substantially neither partially nor fully into abutment in a regular operating state of the hammer drill 10. As a result, a force flux is already prevented in the regular operating state from being able to be passed via the support element 64, which would disadvantageously result in an action contrary to the vibration damping of the damping unit 32 with respect to the vibrations transmitted to the main grip body 37. A force flux 80 applied to the fastening unit 30 and caused by the mentioned vibrations is thus passed via the damping unit 32 as a single force flux path 80a, 80b.
If the force, caused by vibrations or in particular temporary impact pulses—for example as a result of loads caused by dropping—on the bending elements 74, or the end cap 78 rises beyond a design-related maximum value, greater tilting, caused thereby, of the end cap 78 with respect to the main grip body 37 results in the contact surface 68 coming at least partially, on a support contact surface 82, into touching, in particular supporting contact with the support surface 70. Via the support contact surface 82, a part of the force flux 80 applied to the fastening unit 30 can now flow off via the support element 64 rather than via the damping unit 32. An additional force flux path 80a, 84 forms temporarily as a bypass to the force flux path 80a, 80b via the damping unit 32.
Depending on the force occurring as an overload, a size of the support contact surface 82 changes such that an increasing overload force is accompanied by an increasing size of the support contact surface 82. Advantageously as a result, a larger part of the force flux 80 applied to the fastening unit 30 is increasingly passed via the additional force flux path 80a, 84 acting as a bypass.
In particular for handle devices 24, 26 according to the disclosure which have a known clamping band device 40 and which can be released or fixed by relative screwing of the grip unit 36 with respect to the fastening unit 30, it may be advantageous for at least one torsion inhibiting means 86 to be provided between the fastening unit 30 and the grip unit 36, said torsion inhibiting means 86 limiting torsional moments acting on the damping unit 32 to a maximum in the event of torsion of the grip unit 36 relative to the fastening unit 30.
In the example according to
Instead of the two pairs, shown here by way of example, of recesses 88 and torsion blades 90, a different number—preferably one pair, three pairs or four pairs—can also advantageously be provided. Also, the arrangement of the recess and torsion blade between the support element 64 and fastening unit 30 can be exchanged or else formed in an alternating manner.
Furthermore, further configurations of torsion inhibiting means 86, for example pins, in particular eccentrically placed pins through the first and second abutment surfaces 44, 46, surface structures in the first and second abutment surfaces 44, 46 or additional sleeve-like engaging elements between the fastening unit 30 and overload protection unit 34, in particular support element 64, are known to a person skilled in the art, and can advantageously be used in a modification of the exemplary embodiment according to the disclosure without impairing the inventive concept.
The angle grinder or cut-off grinder 110 has a housing 112 having a main direction of extension 190. The handle device 124, 126 is arranged, in particular fitted, on a drive head region 192 of the housing 112, in a direction substantially perpendicular to the main direction of extension 190.
The handle device 124, 126 has a similar structure to the exemplary embodiments already known from the preceding text according to
The fastening unit 130 of the handle device 124, 126 comprises in this example a threaded pin 194 at an end remote from the grip unit 136, as can be seen particularly well in
Instead of the threaded pin 194, other form-fitting and/or force-fitting elements, for example latching pins, latching hooks, eyelets or the like, may be provided on the fastening unit 130, said elements interacting with matching receiving and holding elements known to a person skilled in the art, instead of the receiving bore, such that the handle device 124, 126 can be connected, in particular releasably, to the housing 10, 110 of a hand tool.
In its mode of operation, in particular with respect to the damping of vibrations and protection against overloading of the damping unit 132, the exemplary embodiment according to
The exemplary embodiment according to
In its mode of operation, in particular with respect to the damping of vibrations and protection against overloading of the damping unit 132, the exemplary embodiment according to
The embodiment according to
In its mode of operation, in particular with respect to the damping of vibrations and protection against overloading of the damping unit 132, the exemplary embodiment according to
Proceeding from the exemplary embodiments, described in the preceding text, of a handle device 24, 26, 124, 126 according to the disclosure, it will be easy for a person skilled in the art to make obvious modifications. In particular, for example by varying the design and/or the number of bending elements 74, 174, advantageous configurations of a handle device according to the disclosure can be achieved. In addition to the configuration, shown here, as an auxiliary handle 26, 126, the inventive concept can advantageously also be used as a main handle depending on the hand tool taken as a basis, for example in the case of hand tools which have a mainly stem-like elongate form.
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10 2011 078 376 | Jun 2011 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP2012/061309 | 6/14/2012 | WO | 00 | 4/18/2014 |
Publishing Document | Publishing Date | Country | Kind |
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WO2013/000724 | 1/3/2013 | WO | A |
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International Search Report corresponding to PCT Application No. PCT/EP2012/061309, mailed Aug. 22, 2012 (German and English language document) (8 pages). |
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