Hand machine tool adjustable front handle

In order to provide a hand machine tool comprising PA1 an elongated housing, PA1 a drive motor which is arranged in the housing and with which a tool holder can be driven via a miter gear, PA1 a first handle unit arranged on a housing section located close to the tool holder and aligned transversely to a longitudinal axis of the housing PA1 and a second handle unit arranged on the housing, with which the alignment of the first handle unit relative to the axis of rotation of the tool holder may be varied, it is suggested that the first handle unit be held for guidance in an adjusting guide means on the housing and in this adjusting guide means be adjustable within an angular range of at least 90.degree. about a longitudinal axis of the housing between several possible positions and be fixable in a positive-locking manner in the respective position.

The invention relates to a hand machine tool comprising an elongated
 housing, a drive motor which is arranged in the housing and with which a
 tool holder can be driven via a miter gear, a first handle unit arranged
 on a housing section located close to the tool holder and aligned
 transversely to a longitudinal axis of the housing and a second handle
 unit arranged on the housing.
 Hand machine tools of this type are known from the state of the art. Hand
 machine tools of this type are, in many cases, designed as angle grinders
 which are provided for a plurality of grinding and cutting work.
 In this respect, the handling capability of the machine tool is dependent
 on the alignment of the first handle unit relative to an axis of rotation
 of the tool holder.
 The object underlying the invention is therefore to provide a hand machine
 tool, with which the alignment of the first handle unit relative to the
 axis of rotation of the tool holder can be varied.
 This object is accomplished in accordance with the invention, in a hand
 machine tool of the type described at the outset, in that the first handle
 unit is held for guidance in an adjusting guide means on the housing and
 in this adjusting guide means can be adjusted within an angular range of
 at least 90.degree. about the longitudinal axis of the housing between
 several possible positions and can be fixed in a positive-locking manner
 in the respective position.
 The advantage of the inventive solution is to be seen in the fact that as a
 result of the guidance of the handle unit in the adjusting guide means a
 complete detachment of the handle unit from the housing is avoided during
 the adjustment and so the handle unit always remains in connection with
 the housing and, on the other hand, due to the positive-locking fixing the
 possibility is also created of securely fixing the handle unit in the
 intended position which is desirable for a good equipment safety of the
 hand machine tool since any undesired releasing of the handle unit in the
 respective position, which would be possible with a force-locking fixing,
 can thus be prevented.
 A positive-locking fixing is thereby to be understood as all the
 possibilities for realizing this which provide for one positive-locking
 element to engage in another. In this respect, one of the positive-locking
 elements can, in the simplest case, be designed as a rippled or wavy
 surface, the other positive-locking element then engaging in its recesses
 with a nose.
 The adjusting guide means may be designed in the most varied of ways.
 One advantageous solution provides for the adjusting guide means to
 comprise a guide path guiding a guide member connected to the first handle
 unit in a positive-locking manner between the various positions.
 In principle, it would be conceivable to design the guide path completely
 independently of the outer contour of the housing.
 However, in order to be able to integrate the guide path into the housing
 in a simple manner it is preferably provided for the guide path to extend
 along an outer contour of the housing.
 It is particularly advantageous when the guide path is arranged so as to be
 recessed in relation to the outer contour of the housing so that the guide
 path can be protected against any type of damage.
 A particularly favorable design of the adjusting guide means provides for
 the adjusting guide means to have at least one guide bar which extends in
 the direction of guidance and behind which the guide member connected to
 the handle unit engages.
 As a result, a particularly simple and functional adjusting guide means can
 be realized.
 With respect to the possibilities for the positive-locking fixing of the
 handle unit in the various positions, no further details have so far been
 given. It would, for example, be possible to provide the positive-locking
 fixing separately from the guide path. It would, for example, be
 conceivable to arrange the positive-locking elements for the fixing of the
 handle unit in the various positions next to the guide path.
 For reasons of space and for reasons of as simple a constructional solution
 as possible, it is particularly favorable when the guide bar is provided
 with a row of positive-locking elements which can be brought into
 engagement with corresponding positive-locking elements on the guide
 member connected to the first handle unit.
 The guide member is, as a result, not only provided for the purpose of
 guiding the handle unit in the adjusting guide means but it is also used
 at the same time for the purpose of realizing the positive-locking
 connection in the respective positions.
 In order to ensure that the positive-locking elements transfer into their
 positive-locking position and remain in it, a securing element is
 preferably provided which acts on the positive-locking elements in order
 to keep these in their positive-locking position and when they are not in
 their positive-locking position to transfer them into it.
 A particularly simple design of such a securing element from a
 constructional point of view provides for this to comprise a retaining
 spring which acts on the positive-locking elements in such a manner that
 they transfer into their positive-locking position, and remain in this
 position.
 With respect to the arrangement of the securing element, the most varied of
 possibilities are conceivable. For example, it would be conceivable to
 arrange the securing element as a separate element independent of the
 adjusting guide means. However, a particularly favorable solution provides
 for the securing element to be arranged so as to be supported on the
 adjusting guide means.
 An alternative solution provides for the securing element to be arranged in
 the handle unit.
 In order to ensure that the positive-locking elements transfer from their
 positive-locking position into their non-positive-locking position and
 thus the handle unit is movable in the adjusting guide means, it is
 necessary to provide an actuating element for the securing element. Such
 an actuating element could, for example, be an additional element provided
 in the handle unit, such as, for example, an actuating lever or an
 actuating knob.
 A particularly simple solution from a constructional point of view provides
 for the securing element to be actuatable via a handle of the handle unit,
 for example, in the case of a retaining spring to be acted upon contrary
 to the force of the spring.
 In conjunction with the preceding description of the individual
 embodiments, no further details have so far been given as to how the
 fixing of the first handle unit is intended to be brought about in the
 respective positions. It would, for example, be adequate, in order to hold
 the handle unit in this position, to fix it in a positive-locking manner
 in this position also with a certain play.
 In order to facilitate a secure and precise working with the hand machine
 tool it is, however, particularly advantageous when the first handle unit
 can be positioned on the housing free from play in the respective position
 fixed in a positive-locking manner by means of a clamping device.
 The advantage of this solution is to be seen in the fact that the
 positioning of the handle unit relative to the housing is indeed possible
 by way of the positive-locking fixing thereof but this positioning is
 still subject to play, wherein play does not have a disadvantageous effect
 on fundamental safety aspects which are realized by the adjusting guide
 means and the positive-locking fixing in the respective position. As a
 result of the additional fixing free from play by means of a clamping
 device the desired, rigid and precise alignment of the handle unit in
 relation to the housing is, however, ensured.
 Such a clamping device may be realized in various ways. A particularly
 favorable solution provides for the clamping device to have a clamping
 element, with which a support element of the handle unit can be abutted
 against the housing in a clamped manner.
 The clamping element which must itself engage on the housing in order to
 abut the support element on the housing in a clamped manner is preferably
 designed such that it engages on the guide member guided in the adjusting
 guide means.
 The clamping element could be designed, for example, as a resiliently
 elastic element.
 A particularly favorable solution does, however, provide for the clamping
 element to be designed as a clamping gear element, with which large forces
 for the clamping of the handle unit in relation to the housing may be
 realized in a simple manner.
 A particularly simple and inexpensive solution provides for the clamping
 element to be designed as a clamping spindle.
 With respect to the possible positions of the handle unit in the adjusting
 guide means, no further details have so far been given. It would, for
 example, be conceivable to realize the positive-locking fixing such that
 an essentially continuous positioning of the handle unit along the
 adjusting guide means is possible.
 On the other hand, it is of advantage in order to bring about a secure,
 positive-locking positioning of the handle unit when the first handle unit
 can be fixed discontinuously in a positive-locking manner. A
 discontinuous, positive-locking fixing creates the possibility of
 specifying individual fixing points from the outset which can then be
 realized in a constructionally simple manner.
 In principle, it would be possible to realize the discontinuous,
 positive-locking fixing of the handle unit such that the first handle unit
 can be fixed discontinuously in a positive-locking manner in steps of
 smaller than to equal to 90.degree..
 It is, however, even more advantageous when the first handle unit can be
 fixed discontinuously in a positive-locking manner in steps of smaller
 than to equal to 30.degree..
 With regard to the type of fixing of the handle unit in the adjusting guide
 means, nothing has so far been said concerning essential positions which
 are significant for the use of the hand machine tool. One advantageous
 solution provides in this respect for the handle unit to be aligned in one
 of the possible positions approximately parallel to the axis of the tool
 holder. This solution ensures that with the possible positions of the
 handle unit such a position can also be reached which preferably permits
 the use of the inventive hand machine tool for the cutting of objects with
 a favorable ergonomic handling.
 Another solution advantageous for the ergonomic handling provides for the
 handle unit to be aligned in one of the possible positions approximately
 at right angles to the axis of the tool holder since, with this alignment,
 it is ensured that roughing and grinding work, in particular, can be
 carried out advantageously with the inventive hand machine tool.

One embodiment of an inventive, motor-driven hand machine tool illustrated
 in FIGS. 1 and 2 comprises a housing 10, in the motor housing section 12
 of which a motor, for example, an electromotor is arranged. Furthermore, a
 gear housing section 14 adjoins the motor housing section 12 and in this
 section a miter gear is, for example, arranged which drives a tool holder
 16 which is rotatable about an axis 18 which, for its part, extends
 transversely to a longitudinal axis 20 of the housing 10.
 The tool holder 16 is designed, for example, as a holder for a grinding
 disc 22 which forms the driven tool.
 A cover 24 for the tool 22 can preferably be fixed, in addition, on the
 gear housing section 14, wherein the cover 24, for example, engages around
 a cylindrical holding attachment on the gear housing section 14, which is
 arranged cylindrically to the axis 18, with a holding clip 28.
 For the guidance of the hand machine tool, a first handle unit 30 is
 provided in the region of the gear housing 14 and, in addition, a
 possibility for holding the hand machine tool on a side of the motor
 housing section 12 located opposite the gear housing section 14. This is
 realized, for example, in the form of a second handle unit 32, wherein the
 latter preferably extends away from the motor housing section 12
 approximately in the direction of the longitudinal axis.
 Furthermore, a switch 34 is preferably provided in the handle unit 32 for
 switching on the hand machine tool.
 As illustrated in FIGS. 1 and 2, an adjusting guide means for the first
 handle unit 30, which is designated as a whole as 40, is provided in the
 gear housing section 14, preferably in a segment 38 of the gear housing
 section 14 located close to a connection flange 36 for the fixing of the
 gear housing section 14 on the motor housing section 12 and so, as
 illustrated in FIG. 2, the first handle unit 30 can be positioned in an
 angular range W about the longitudinal axis 20 in a plurality of
 individual positions 42, wherein these individual positions 42 facilitate
 different handling of the hand machine tool. For example, the grinding
 disc 22 can be expediently used in the position 42a as a cutting disc for
 separating objects, wherein in the position 42a a central axis 44 of the
 handle unit 30 is aligned approximately parallel to the axis 18, about
 which the grinding disc 22 rotates.
 In contrast thereto, the grinding disc 22 can preferably be used in a
 position 42b for roughing or sanding. The position 42b preferably
 corresponds to the position of the handle unit 30 suitable for roughing or
 sanding for right-handed users whereas a position 42c corresponds to the
 position for roughing or sanding for left-handed users.
 The angular range W is preferably in the order of magnitude of
 approximately 180.degree..
 In addition, further intermediate positions can be realized, such as, for
 example, the position 42d, which can be selected depending on the location
 and purpose of use.
 As illustrated in FIGS. 2 to 4, the adjusting guide means 40 comprises two
 grooves 44 and 46 which are formed into the segment 38, extend parallel to
 one another in azimuthal direction 48 in relation to the longitudinal axis
 20 of the housing 10 and are separated from one another by a guide web 50.
 The guide web 50 bears on its upper side 52 a guide element which is
 designated as a whole as 54, extends, as illustrated in FIGS. 3 and 5, in
 the azimuthal direction 48 with its center line 56 and thereby rests with
 a central area 58 on the upper side 52 of the web but projects beyond the
 guide web 50 into the groove 44 or the groove 46 with guide bars 60 and
 62, respectively, which adjoin the central area 58 on both sides thereof
 in continuation thereof. Furthermore, each of the guide bars 60 and 62 is
 provided with locking recesses 64 and 66 located opposite one another in
 relation to the center line 56, wherein the locking recesses 64 and 66
 have, for example, an angular distance wa which is in the order of
 magnitude of 15.degree..
 The guide element 54 can preferably be screwed onto the guide web in the
 state preshaped in accordance with the upper side 52 of the web with
 screws passing through the guide element 54 in screw holes 68 and engaging
 in the guide web 50.
 Preferably, the guide element 54 of the adjusting guide means 40 is
 arranged on the guide web 50 and the guide web 50 designed such that an
 upper side 70 of the guide element 54 resting on the guide web 50 is
 aligned with an outer contour 72 of the segment 38 of the gear housing
 section 14 and extends in accordance with the shape of the outer contour
 72.
 In the simplest case, the outer contour 72 is thereby designed as a surface
 which is approximately cylindrical with respect to the longitudinal axis
 20 and preferably circular-cylindrical. It would, however, also be
 conceivable to design the outer contour 72, for example, as an elliptical
 surface extending symmetrically with respect to the longitudinal axis 20.
 The adjusting guide means 40 comprises, in addition, a guide member, which
 is designated as a whole as 80 and which has a central section 82 engaging
 over the upper side 70 as well as, proceeding from this, side sections 84,
 86 engaging in the grooves 44 and 46, with holding sections 88, 90 which
 extend in the direction towards one another and engage behind the guide
 bars 60 and 62 on their undersides 92 and 94 located opposite the upper
 side 70 so that the guide member 80 is thus movable in the azimuthal
 direction 48 but is guided so as to be unreleasable from the guide element
 54 of the adjusting guide means 40.
 In addition, the holding sections 88, 90 comprise locking projections 96
 and 98 which can be brought into engagement with the locking recesses 64
 and 66 in order to facilitate a positive-locking securing in position of
 the guide member 80, wherein the holding sections 88 and 90 of the guide
 member 80 can dip into the grooves 44 and 46 to such an extent that the
 locking projections 96 and 98 are movable along the undersides 92 and 94
 of the guide bars 60 and 62 in the azimuthal direction and by lifting the
 guide member in relation to the grooves 44 and 46 the locking projections
 96 and 98 can be brought into engagement with the respectively reachable
 locking recesses 64 and 66.
 In order to ensure that the guide member 80 does not endeavor to always dip
 into the grooves 44 and 46 with the holding sections 88 and 90 to such an
 extent that the guide member is in its position freely movable in the
 adjusting guide means 40 in the azimuthal direction 48 but rather the
 guide member 80 always endeavors to transfer into a position in the
 adjusting guide means 40 which is secured in a positive-locking manner and
 in which the locking projections 96 and 98 engage in the locking recesses
 64 and 66, a pressure spring is provided as securing element 100 and this
 is supported with one end 102 on the upper side 70 of the guide element 54
 and acts with an oppositely located end 104 against a pressure surface 106
 of the central section 82 of the guide member 80 facing the upper side 70
 and thus keeps the central section 82 always at the maximum possible
 distance from the upper side 70 of the guide element 54 so that, as a
 result, the locking projections 96 and 98 always endeavor to engage in the
 locking recesses 64 and 66 from the undersides 92 and 94 of the guide bars
 60 and 62. In this position secured in a positive-locking manner, the
 holding sections 88 and 90 preferably abut with contact surfaces 108 and
 110 facing the undersides 92 and 94 of the guide bars 60 and 62. A
 threaded bore 120 is provided, in addition, in the central section 82 of
 the guide member 80 and this is arranged approximately in the center of
 this section and a threaded pin 122, which is fixed on a handle 124 of the
 handle unit 30, can be screwed into it.
 Although the handle unit 30 is, on the one hand, guided in the adjusting
 guide means 40 and, on the other hand, secured in a positive-locking
 manner as a result of the guide member 80, which, on the one hand, engages
 behind the guide bars 60 and 62 with the holding sections 88 and 90 and,
 on the other hand, engages in the locking recesses 64 and 66 with the
 locking projections 96 and 98, so that the handle 124, which is connected
 to the guide member 80 via the threaded pin 122 screwed into the threaded
 bore 120 thereof, is also securely guided and secured in a
 positive-locking manner on the gear housing section 14 by way of the
 adjusting guide means 40 with the guide member 80, the handle 124 is, as a
 result, not rigidly aligned in relation to the gear housing section 14 but
 rather movable at least with play since the securing element 100 can
 merely serve to keep the locking projections 96 and 98 in engagement with
 the locking recesses 64 and 66 but not prevent any inclination of the
 guide member 80 in relation to the guide element 54.
 For this reason, a clamping device is provided which has a support element
 130 which engages over the guide member 80 and thus the two grooves 44 and
 46 as well with an upper part 132 and extends with its side parts 134 and
 136 from the upper part 132 in the direction of the housing section 14 so
 that the side parts 134 and 136 can be placed with their bottom surfaces
 138 and 140 on the outer contour 72 of the segment 38 of the housing
 section on both sides of the grooves 44 and 46. The side parts 134 and 136
 are preferably elements of an apron extending around the central section
 82 of the guide member 80.
 The upper part 132 of the support element 130 forms with its upper side
 facing away from the guide member 80 a support surface 142, against which
 the handle 124 can be supported with an end face 144 when the threaded pin
 122 passes through an opening 133 in the upper part 132 and is turned into
 the threaded bore 120 of the guide member 80. In this case, the guide
 member 80 is drawn in the direction of the upper part 132 of the support
 element 130 so that this finally abuts on the guide bars 60 and 62 with
 its holding sections 88. As a result, the guide member 80 forms an
 abutment so that the handle 124 is increasingly moved with its end face
 144 against the support surface 142 of the upper part 132 and thus the
 entire support element 130 is moved in the direction of the outer contour
 72 until the bottom surfaces 138 and 140 of the side parts 136 rest on the
 outer contour 72 on both sides of the grooves 44 and 46, wherein, in the
 end, a rigid fixing of the handle 124 free from play results in relation
 to the gear housing section 14 due to the fact that the end face 144 of
 the handle 124 rests on the support surface 142 of the support element
 free from play and this again rests with the bottom surfaces 138 and 140
 free from play on the outer contour of the segment 38 of the gear section
 14 next to the grooves 44 and 46 in a clamped manner, wherein, in the long
 run, the clamping of the end face 144 of the handle against the support
 element 130 and the clamping of the support element 130 against the outer
 contour of the segment 38 of the housing section 14 is achieved by way of
 the threaded pin 122 as clamping element which, for its part, thereby
 draws the guide member 80 against the guide element 54.
 If, on the other hand, the threaded pin 122 is turned out of the threaded
 bore 120, the clamping between the end face 144 of the handle 124 and the
 support element 130 is released and also the clamping between the support
 element 130 and the outer contour of the segment 38 of the gear housing
 section 14 and play can be achieved between the end face 144 and the
 support element 130 due to further turning such that due to action on the
 handle 124 in the direction of the grooves 44, 46 the guide member can be
 pressed into the grooves 44, 46 against the force of the securing element
 100 to such an extent until the locking projections 96, 98 become
 disengaged from the locking recesses 64, 66 in the guide element 54 and
 the guide member 80 is movable along the guide element 54 in the adjusting
 guide means 40 into one of the positions 42.
 In a second embodiment of an inventive hand machine tool, illustrated in
 FIGS. 6 and 7, those parts which are identical to those of the first
 embodiment are provided with the same reference numerals and so with
 respect to their description reference is made in full to the comments on
 the first embodiment.
 In contrast to the first embodiment, the guide element 54 of the second
 embodiment is designed such that it does not have in the region of its
 guide bars 60, 62 locking recesses penetrating them in their entire
 thickness but, as illustrated in FIG. 7, in particular, a wavy-like or
 ripple-like structure on a side of the guide bars 60, 62 facing the
 grooves 44, 46, the indents of this structure forming the locking recesses
 64, 66.
 Furthermore, the holding sections 88 and 90 of the guide member are each
 provided with a locking projection 96, 98 which is in a position to dip
 into one of the indents forming the locking recesses 64, 66 and thus to
 serve for a positive-locking fixing of the guide member 80 on the guide
 element 54.
 The second embodiment represents altogether a variation of the first
 embodiment.
 In a third embodiment of an inventive hand machine tool, illustrated in
 FIGS. 8 to 10, the adjusting guide means 40 merely comprises one groove
 44', guide bars 60' and 62', which, as illustrated in FIG. 8, are
 connected at their ends to the guide element 54' via end sections 63,
 projecting beyond the lateral, oppositely located walls 45a and 45b of
 this groove.
 An intermediate space 65, which is penetrated by the threaded pin 122 of
 the handle 124, thus remains between the guide bars 60' and 62'. In the
 third embodiment, the guide member 80 is located as a whole in the groove
 44' and has on its side facing the guide bars 60' and 62', on the one
 hand, the support surfaces 108 and 110 and, on the other hand, the locking
 projections 96 and 98 which project upwardly beyond the support surfaces
 108 and 110 and can be brought into engagement with the locking recesses
 64 and 66.
 The securing element 100 designed as a pressure spring is supported in the
 third embodiment, in addition, on a groove base 47 of the groove 44' and
 acts on an underside 81 of the guide member 80 in such a manner that the
 guide member 80 is always pressed in the direction of the guide bars 60'
 and 62'.
 In the third embodiment, the guide bars 60' and 62' are preferably arranged
 in relation to the outer contour 72 of the segment 38 so as to be likewise
 recessed in edge grooves 61 and 63 bordering laterally on the groove 44'
 and a side wall 150 and 152, which is upright in relation to the guide
 bars 60' and 62' and reaches as far as the outer contour 72 of the segment
 38, is preferably formed thereon.
 The support element 130 is provided on the guide bars 60' and 62', namely
 lying on an upper side 154 and 156, respectively, thereof, this support
 element being part of the clamping device but in the third embodiment not
 being supported directly on the outer contour 72 but likewise on the guide
 bars 60' and 62'.
 The support element 130 is thereby designed, in the simplest case, as a
 plate with a central bore 133 which is penetrated by the threaded pin 122
 which, exactly as in the first embodiment, is screwed into a threaded bore
 120 which, in the third embodiment, is, however, arranged in the guide
 member 80 located in the groove 44'.
 For the clamping of the handle 124 free from play this is likewise
 supported with its end face 144 on the support surface 142 of the support
 element 130, wherein this can, in turn, be clamped against the upper side
 154 and 156 of the guide bars 60' and 62' whereas, on the other hand, the
 threaded pin 122 serving as clamping element abuts the guide member 80
 with the support surfaces 108 and 110 against the undersides 92, 94 of the
 guide bars 60' and 62'.
 The third embodiment functions in the same way as the first embodiment and
 so reference can be made in full to the comments on the first embodiment.
 In a variation not only of the first but also of the second or third
 embodiment it is possible to design one of the guide bars 60 or 62 without
 locking recesses 64 or 66 so that a positive-locking fixing is possible
 only with the respectively other guide bar 62, 60 and the guide member 80.
 This facilitates the release of the positive-locking fixing to the extent
 that after releasing the threaded pin 122 in the threaded bore 120 of the
 guide member 80 a tilting of the guide member 80 and thus merely a tilting
 of the handle 124 in a tilting direction 160 is required in order to bring
 the locking projections 98 out of engagement with the locking recesses 66
 of the guide bar 62 while the guide member 80 is supported with the
 support surfaces 108 on the guide bar 60 not provided with any locking
 recesses 64. Such a release of the positive-locking connection between the
 locking projections 98 and the corresponding locking recess 66 is
 simplified in comparison with the embodiments described thus far to the
 extent that it is not the entire handle 124 which has to be displaced in
 the direction of the groove 44 in order to press the guide member 80
 likewise as a whole into the groove 44; however, the securing in the
 respective position 42 is less reliable for as long as the handle is not
 clamped free from play.
 In a further variation, in particular, a variation of the first embodiment
 it would also be possible to omit the support element 130 for the clamping
 of the handle and bring about the clamping of the handle 124 in relation
 to the segment 38 by the threaded pin 122 being supported with its end
 face 162 on the upper side 70 of the guide element 54.
 The present disclosure relates to the subject matter disclosed in German
 Application No. 198 54 468.5 of Nov. 25, 1998, the entire specification of
 which is incorporated herein by reference.