EP2252430A1

EP2252430A1 - Hand-held power tool, in particular hand-guided grinding machine

Info

Publication number: EP2252430A1
Application number: EP08872878A
Authority: EP
Inventors: Attila Nagy
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2008-02-25
Filing date: 2008-11-12
Publication date: 2010-11-24
Anticipated expiration: 2028-11-12
Also published as: RU2010139286A; WO2009106163A1; CN101959646B; EP2252430B1; RU2495740C2; DE102008010977A1; CN101959646A; US20100323595A1; US8512104B2

Abstract

A protective hood is provided for a hand-held power tool, in particular a hand-guided grinding machine, the tool of which is at least partially covered by said protective hood for which protective layers, which support the protective hood in an elastically compliant manner in the direction of rotation, can be adjusted by locking positions of a locking arrangement.

Description

title

Hand tool, in particular hand-guided grinding machine

The invention relates to a hand tool, in particular a hand-held, preferably designed as an angle grinder grinding machine, according to the preamble of claim 1.

State of the art

In one known from EP 0 583 270 Bl, designed as a hand-held angle grinder hand tool a protective hood is provided for the carried by a drive spindle tool, which arranged on a hub part on the bearing neck of the housing side bearing flange of the drive spindle and in several rotational positions via a locking device is rigidly fixate.

The hub part is designed as a hat-shaped metal cap, which is axially fixed to the bearing neck against this axially positively fixed.

The locking device with effective between the hub portion and the bearing neck locking members comprises a between a shoulder of the bearing flange and the brim of hutförmi- gene, the hub portion forming metal sheet lying annular body which is rotationally fixed to the bearing flange and the one against the brim and axially, ie against the brim has resiliently biased ring portion. This ring portion carries as a locking member a locking lug, which correspond to the side of the brim circumferentially spaced recesses as receiving locking members. The bolt nose bearing Ring section is provided with an actuating button, which is to lift the torsion-free locking manually to adjust the rotational position of the guard.

In a further, known from DE 37 44 218 Al locking device for a rotatably supported on the bearing neck of the drive spindle of an angle grinder protective locking the locking access is not axially, but radially and in a version of a two-armed lever, the housing side via a to Axis of the work spindle is articulated parallel pivot axis. The pivot lever is provided at its one end with a locking member in the form of a locking lug, which are assigned to a bearing neck enclosing hub part of the guard, circumferentially and circumferentially spaced radial recesses. The other arm of the rocker arm serves as an actuating button and is spring-loaded in the direction of engagement of the locking lug in the respective receptacle corresponding pivoting direction.

Also in this solution, the guard is rotationally rigidly supported in their respective locked rotational position.

The torsionally rigid support has the consequence that in case of tool damage, for example when bursting a grinding wheel and an associated wedging of disc parts against the protective hood or jamming of a workpiece between the tool and protective cover, in particular the protective cover and / or their locking can be damaged.

Disclosure of the invention

The invention is based on the object, without substantial additional effort such cases of damage to avoid or at least reduce their extent of damage as well as, if necessary, independently, to provide a particularly simple and montageemäßig favorable locking arrangement. This object is achieved with the features of claim 1. The dependent claims indicate expedient refinements and with regard to the design of the locking arrangement also independent training.

The starting point for the solution according to the invention is the determination of the protective cover provided peripherally covering the tool in a rotational position predetermined by the conditions of use and the purpose of work by a respective locking arrangement. By means of this locking arrangement, a respective desired position is thus predetermined for the protective hood, from which the protective hood can yield in the circumferential direction while maintaining the locking with the corresponding application of force due to the elastically yielding support. The elastically yielding support may be provided on the part of the protective hood and / or on the part of the locking device, and in particular an arrangement is expedient in which the protective hood is resiliently supported in the driving direction of rotation of the drive spindle. Thus, according to the invention, a respective protective layer is provided by a pivoting area for the protective hood

Locking position determines within which the guard is pivotable at elastically resilient support to this locking position.

A particularly simple and expedient construction results when the protective hood is resiliently supported by the spring means in the circumferential direction of the bearing neck in their respective locking position, via which the locking members of the locking device are biased to their engaged position.

This can be achieved particularly easily with spring means in the form of a U-shaped bent leg spring which has a locking leg and fastening legs connected via its U-shaped vertex arc, of which the fastening leg is fixed on the housing side and the locking leg is provided on the side of the hub side clamping neck - A -

Locking members engaging locking members and extends transversely to the axis of the drive spindle.

In the context of the invention, the leg spring can be arranged with the spring plane extending transversely to the axis of the drive spindle or, which is a preferred solution according to the invention, with the spring plane extending in the direction of the axis of the drive spindle. In both cases, by the design as a leg spring and the connection of the legs on the vertex and a compliance in the direction of extension of the legs to achieve, resulting in the elastically resilient support of the guard in a protective layer to a respective given locking position.

Conveniently, the leg spring is formed as a leaf spring with in the direction of the spring plane over the vertex arc against each other, each transverse to the spring plane flat locking leg and mounting leg, which can be high clamping forces and for the elastic support Ab support high support forces realize for locking. These forces can be influenced in their height as well as in their relation to one another further by the fact that the fastening leg and the locking leg extend at an angle to one another in the direction of the spring plane, so that a tilting of the leg spring results in the area of the vertex arc. Such a set also has the advantage that the legs extend at an angle to one another transversely to the spring plane, so that a fastening screw passing through the fastening leg in the vicinity of the vertex arc lies outside the overlapping area of the locking leg and is thus easily accessible.

Further advantages and expedient embodiments can be taken from the further claims, the description of the figures and the drawings. Show it: 1 is a schematic plan view of a hand tool in the form of a hand-held grinding machine parallel to the drawing plane, a tool, preferably in the form of a grinding or cutting disc, supporting drive spindle and the drive spindle enclosing bearing neck on which a protective cover is rotatably mounted, which is supported by a locking arrangement, which is in its locking position, in a protective layer,

2 is a representation corresponding to FIG. 1, in which the locking arrangement is shown in its unlocked position, FIG.

Fig. 3 is a schematic representation corresponding to a

Section III-III in Fig. 1, wherein the locking arrangement comprises spring means whose spring plane transversely, in particular perpendicular to the plane, thus approximately in the longitudinal direction of the axis of the drive spindle, that is axially,

FIG. 4 shows a basic illustration corresponding to FIG. 3, in which, unlike FIG. 3, spring means are shown whose spring plane extends along the plane of the drawing, in particular parallel to the plane of the drawing and thus transversely, in particular radially to the axis of the drive spindle, and

5 to 7 separate representations of the illustrated in Fig. 1 to 3 spring means which are formed in the form of a leg spring having a locking leg and a mounting leg, Fig. 5 according to the illustration of FIG. 1, the leg spring in side view across the Spring level and in one of their locking position corresponding spring position and Fig. 6, the leg spring according to FIG. 7 illustrates in a side view according to FIG. 5 different spring positions of the leg spring, in which the leg spring is initially shown in solid lines in its unstressed basic shape, following - dash-dotted - in the direction of its span plane offset and biased, in one of the Fig. 1 corresponding locking position and finally, following, dashed lines in one of Fig. 2 corresponding unlocking position in which the locking leg is further swung and accordingly biased more.

1 and 2 are mutually corresponding representations of a power tool in the form of a hand-held grinding machine 1 shown in a side view. The grinding machine 1 is formed in the embodiment as an electrically driven machine and has a housing 2, which, which is not shown in a known manner receives a drive with motor and nachgeordne- tem gear and that in the embodiment axially at one of its ends with a bearing flange 3 connected, is screwed in the embodiment. Associated axial screw connections are indicated at 4.

The bearing flange 3 is, as illustrated in Fig. 3, penetrated by a drive spindle 5, the driving direction of rotation is denoted by 38, and terminates in a bearing neck 6. The drive spindle 5 extends to the bearing neck 6, at least in approximation coaxially. The rotational and longitudinal axis in the drive spindle 5 is denoted by 7. The drive spindle 5 carries at the end auslaufend, which is not shown in detail, a tool 8. The tool 8 is preferably in the form of a rotating grinding or cutting disc. At least over part of its circumference, the tool 8 is enclosed by a protective hood 9, which is mounted on the bearing neck 6 via its hub part

Shape of a clamping neck 10 rotatably guided and the bearing neck 6, which is not shown, is axially fixed. The clamping collar 10 is formed by a laterally, that is, in the direction of the rotational and longitudinal axis 7 to the protective hood 9 projecting and the bearing neck 6 overlapping collar.

According to the work requirements, the protective cover 9 is to set the rotational and longitudinal axis 7 in different rotational positions as protective layers.

This purpose is served by a locking arrangement 11 which, in a first embodiment according to FIGS. 1 to 3, has spring means 12 to which locking members 13 are assigned, to which locking members 14 provided on the part of the protective hood 9 and corresponding to the clamping neck 10 correspond. In the exemplary embodiment provided on the part of the spring means 12 locking members 13 are formed as projecting tabs 15, which correspond to recesses 16 as provided on the side of the clamping neck 10 locking members 14.

The spring means 12 are designed in the embodiment of FIGS. 1 to 3 as a U-shaped leg spring 17 with a locking leg 18, a mounting leg 19 and a U-shaped vertex arch 20 connecting these legs. The spring plane of the U-shaped leg spring 17 extends in the arrangement according to Fig.l to 3 axially, that is, in the longitudinal direction of the rotational and longitudinal axis 7, and thus with respect to the view of FIG. 1 and 2 parallel to the plane, and based on the sectional view of FIG. 3 perpendicular to the plane.

In a corresponding manner, the tabs 15 axially overlap in the recesses 16 axially in their locking position (FIG. 1) and are substantially axially swung out of the recesses 16 as shown in FIG.

This is achieved by the fact that in substantially U-shaped connected locking leg 18 and mounting leg 19th these are offset in the axial direction via the vertex bend 20 extending in the axial direction, so that the legs 18, 19 against each other, and thereby also the handle 21 projecting towards the free end of the locking leg 18, surround an imaginary one determined by the vertex bend 20 Pivoting axis are pivotable.

The U-shaped leg spring 17 is preferably, as shown in FIGS. 1 to 3, designed as a U-shaped leaf spring, namely at the spring plane transverse broad sides 22 and extending in the direction of the spring plane narrow sides 23, in particular from the Fig. 5 to 7 can be seen.

In FIGS. 5 to 7, in particular in FIG. 6, it is also illustrated that, in a plan view of the U-shaped leg spring 17 according to arrow VI in FIG. 5, the locking leg 18 and the fastening leg 19 are preferably at an angle 24 to each other, through which in the plan view of FIG. 5, the screw 4 associated screw hole 25 in the mounting leg 19 at least partially, preferably at least substantially unobstructed to the locking leg 18 and thus a simple screwing of the spring means 12 in the form of the leg spring 17 frontally Bearing flange 3 allows, as shown in FIGS. 1 and 2 can be seen. The entanglement of the leg spring 17 in the region of the vertex arc 20 also gives the possibility of an arrangement of the leg spring 17 with respect to the circumferential direction of the bearing neck 6 in opposite directions extension of locking leg 18 and mounting leg 19, wherein the locking leg 18 transverse to the rotational and longitudinal axis 7 substantially extends tangentially to the bearing neck 6 and, as shown in FIG. 6, in the area provided on the locking leg 18, formed by the tabs 15 locking members 13 bulged radially outward, so that one of the peripheral contour of the clamping neck 10 in the locking area corresponding contour of the locking leg results. An over the mounting leg 19 and the U-shaped vertex arch 20 transversely to the rotational and longitudinal axis 7 substantially unyielding support of the locking leg 18 would have the consequence that in the locked position, the guard 9 rotatably, that is rotationally fixed in the circumferential direction of the bearing neck 6 in their respective rotational position would be fixed.

Such a support of the protective hood 9 via the leg spring 17 in its described embodiment is indeed advantageous over known solutions, since it enables a basic adjustment of the protective hood 9 in different locking positions under simple assembly and design considerations, and thus inexpensively solely due to the resilient compliance of the locking leg 18 in the direction of in Fig. 1 to 3 along the rotational and longitudinal axis 7 extending locking plane. Accordingly, such a locking arrangement already embodies an independent design according to the invention.

Is in the context of the inventive solution, the U-shaped leg spring 17 additionally designed to the effect that the locking leg 18 is not only resilient in the direction of the locking plane, and thus transversely to its extension, but is also connected to the mounting leg 19, that he at corresponding load of the protective cover 9 is resiliently supported in the circumferential direction in its longitudinal direction, it follows depending on the protective hood 9 supported torque corresponding to the elastically yielding support while maintaining the respective locking position in the circumferential direction shifted protective layer. In other words, based on a respective locking position by the elastically yielding support, a sector is determined as the pivoting range, over which the protective layer can change depending on the torque to be supported.

The support in its protective position in the direction of rotation elastically yielding the protective cover 9 in one, or based on a each This locking position is achieved in the pre-formed design by a corresponding resilience of the spring means 12, so the leg spring 17, which in turn is fixed via the mounting legs 19 rigidly to the bearing flange 3, and thus also to the bearing neck 6. In the context of the invention, a corresponding effect can be realized at least partially or additionally by fixing the fastening leg 19 instead of the rigid screw connection 4 via an elastic connection to the bearing flange 3 or another part fixed to the housing.

With regard to the resilient support of the locking leg 18 in the direction of the spring plane and / or with regard to the given by a respective locking position of the locking arrangement 11 starting position for a to this

Starting position by in the direction of rotation elastically yielding support of the guard 9 achievable protective layer, it proves to be useful, the leg spring 17 in the region of its U-shaped apex arc 20 and / or the or outgoing therefrom areas of the locking leg 18 and / or the mounting leg 19 over its cross-section, wherein a preferred solution is shown in Fig. 6, which for the locking leg 18 tapering on its the tabs 15 as locking members 13 bearing bulging portion 26 provides a greater width 27 than for the arc formed by the arc 20, the has a width 28. Corresponding effects can be achieved, possibly also reinforced, by changes in the respective supporting cross-section, for example via recesses, ribbing or the like, which is not shown.

Fig. 7 illustrates positions of the locking leg 18 of the leg spring 17 in its unassembled starting position, which is shown in solid lines. The dot-dashed center position of the leg spring 18 corresponds to a locking position shown in FIG. 1 and a position shown in FIG. 5, in which a swivel travel 29 corresponding clamping force is constructed. The Leg spring 17 is thus biased to its locking position and for displacement in the unlocked position, which is shown in dashed lines as a third position, an enlarged pivoting 30 is overcome, so possibly also with increase in torque applied to the protective cover 9 and optionally to a Actuation of the locking leg 18 leads in the direction of its unlocked position, correspondingly larger biasing forces are constructed.

The solution according to the invention is thus distinguished not only by a robust, simple construction and a sensible handling, but also by great locking reliability.

In particular, it is also ensured by the design according to the invention that even with abruptly occurring torque loads, which may result, for example, when bursting grinding and / or cutting discs and jamming of disc parts, disc fragments and / or other objects between the drive spindle 5 and 9 protective cover , Both the protective hood 9 as well as the locking assembly 11 and / or the drive spindle 5 and their storage are at least normally protected from damage, which cause a replacement of these parts and thus trigger a repair case.

FIGS. 1 to 3, as described, are based on an arrangement of a leg spring 17 with a spring plane extending in the longitudinal direction of the rotational and longitudinal axes 7. FIG. 4 shows, in a representation corresponding to the basic construction of FIG. 3, a deviating arrangement of a U-shaped leg spring 31 which analogously to FIGS. 1 to 3 again has a locking leg 32, a fastening leg 33 and a U-shaped leg 32, 33 connecting vertex arch 34 have. The fastening leg 32 is, as shown symbolically, supported by a screw connection 37, for example, on a support boss 35, which is provided axially projecting on the bearing flange 3. Deviating from the design according to FIGS. 1 to 3, the leg spring 31 is arranged in the solution according to FIG. 4 in such a way that the clamping neck 10 between the illustrated locking position and not shown unlocking position is given a pivoting path 36 for the locking leg 32 which is radial and longitudinal Thus, a plane parallel to the plane of FIG. 4 spring plane with respect to the rotational and longitudinal axis 7 radial engagement of the adjustable via a handle 21 of the locking leg 32 ver gelungsglieder 13 formed by tabs 13. Also in this solution, the leg spring 31 is preferred formed as a leaf spring with extending in the direction of the spring plane narrow sides and lying transverse to the spring plane broadsides 22.

Functionally, taking into account the differences between radial and axial access of the locking members 13 on the clamping neck 10 given each other largely corresponding conditions, which can be additionally accommodated by constructive adjustments in a simple manner, so that for the two in Figs. 3 and 4 analog illustrated embodiments, the statements apply to Fig. 1 to 3 in a corresponding adaptation.

Thus, several solutions are shown by the invention, to specify for the protective hood 9 in their protective layer a pivoting range determined by elastic compliance. This once by the fact that the protective hood in its protective position to a locking arrangement located in a respective locking position has an elastically yielding pivoting range, be it by a torsionally flexible support between the locking members or a rotationally elastic connection located downstream of the protective hood 9. In a further embodiment, an elastically yielding pivoting range can be created for the protective hood 9 in its protective position when the locking arrangement 11 is in a respective locking position relative to the protective hood 9 by elastic attachment of the locking arrangement 11 at the housing. closing Lich, according to the invention, the protective cover 9 in its protective position in befindlicher in a locking position to the hood 9 befindlicher locking arrangement by an inherently elastic design of the locking arrangement an elastically yielding supported pivoting range can be achieved, wherein the elastic in itself education are achieved for example by spring means 12, as they in the form of the leg springs 17 or 31 are explained vorildert.

Claims

claims

1. Hand tool, in particular hand-held grinding machine (1), with a via a drive spindle (5) carried tool (8) and a tool (8) at least partially ü- covering protective hood (9) rotatably mounted on a bearing neck (6) and in the direction of rotation to the bearing neck (6) has at least one protective layer, which is predetermined by a respective locking position of a locking arrangement (11), characterized in that the protective hood (9) is supported in its protective position to their respective locking position in the circumferential direction elastically yielding ,

2. Hand tool according to Claim 1, characterized in that the protective hood (9) is supported torsionally elastic relative to the bearing neck (6).

3. Hand tool according to Claim 1 or 2, characterized in that the locking arrangement (11) for clamping neck (10) fixing locking members (13, 14), one locking member (13) towards its manual aufhebbare locking position to the other locking member (14 ) is biased by spring means (12).

4. Hand tool according to one of claims 1 to 3, characterized in that the protective hood (9) in the drive direction of rotation (38) of the drive spindle (5) is resiliently supported.

5. Hand tool according to Claim 3 or 4, characterized in that the protective hood (9) in its protective position on the spring means (12) of the locking arrangement (11) in the circumferential direction of the bearing neck (6) is resiliently supported and that the part of the spring means ( 12) see locking members (13) of the locking assembly (11) are biased to its locking position.

6. Hand tool according to Claim 5, characterized in that the spring means (12) by a

Leg spring (17, 31) are formed, which has a against the clamping neck (10) resiliently biased locking legs (18, 32) which on the side of the clamping neck (10) provided for locking members (14) accessing locking members (13) and carries a Locking leg (18, 32) angled mounting leg (19, 33).

7. Hand tool according to Claim 6, characterized in that the leg spring (17, 31) is U-shaped bent.

8. Hand tool according to Claim 7, characterized in that the mounting leg (19, 33) expiring from the U-shaped vertex bend (20, 34) of the Schenkelfe- (17, 31) is fixed to the housing side.

9. Hand tool according to one of claims 6 to 8, characterized in that the leg spring (31) has a transversely to the axis (7) of the drive spindle (5) extending spring plane.

10. Hand tool according to one of claims 6 to 8, characterized in that the leg spring (17) has a in the direction of the axis (7) of the drive spindle (5) extending Fe- derebene.

11. Hand tool according to Claim 9 or 10, characterized in that on the locking leg (18, 32) provided locking members (13) as projecting La see (15) are provided.

12. Hand tool according to one of claims 6 to 11, characterized in that the leg spring (17, 31) as a leaf spring with in the direction of the spring plane over the U-shaped vertex bend (20, 34) against each other pivotable, each lying transversely to the spring plane broad sides of locking leg (18, 32) and mounting leg ( 19, 33) is formed.

13. Hand tool according to Claim 12, characterized in that the fastening leg (19, 33) and the locking leg (18, 32) extend in the direction of the spring plane viewed at an angle to each other.

14. Hand tool according to claim 13, characterized in that the leg spring (17, 31) in the area of the U-shaped vertex arc (20, 34) is set.