DE19900402A1 - Power tool, especially angle grinder - Google Patents

Abstract

An electric tool is specified, which can preferably be used as an angle grinder (10), with an elongated motor housing, in which an electric motor is accommodated, with a gear housing at a first end of the motor housing for receiving a gear unit for driving a work spindle, and with a handle part (25) which is rotatably attached to a second end (24) of the motor housing and in which a handle switch (32) is arranged. The handle part (25) can be rotated relative to the second end (24) of the motor housing into at least four predetermined angular positions, which are preferably offset from one another by an angle of 90 °, and can be locked therein (FIG. 2).

Description

The invention relates to a power tool, in particular a Angle grinder, with an elongated motor housing, in which a Electric motor is included, with a gear housing on egg nem first end of the motor housing for receiving a transmission to drive a work spindle, and with a handle part that is rotatably attached to a second end of the motor housing and in which a handle switch is arranged.

Such a power tool is from DE 195 46 328 A1 knows.  

The known power tool is designed as an angle grinder det and has a bow-shaped handle with a handle scarf ter on which is rotatably fixed at the end of an engine housing and in a total of three Win, each offset by 90 ° kelp positions is rotatable with respect to the motor housing. This enables the right angle grinder for both right-handers as well as for left-handers in a particularly ergonomic way hold if you take into account that in addition in the front loading rich of the motor housing still a second, stalk-shaped training The handle is either on the right or left of the housing can be screwed. Furthermore, such a Ver Possibility to turn the angle grinder between Cut-off and rough grinding enables, with Cut-off loops either with one to the right out of the Gear head protruding grinding spindle or with a after Grinding spindle protruding from the gear head on the left can be processed.

To lock in the various angular positions are on Recesses facing the handle end of the motor housing provided in which an axially biased latches intervening element. If the handle part from a Winkelpo sition in another angular position, so must first a handle to be operated to lock element against the spring tension in the axial direction from the be release the relevant recess, so that the handle part ver can be rotated until in the next predetermined angular position tion the locking element again in a projection continuous  

In a further power tool, which from DE 40 21 277 A1 is known and that as a grinder, hedge trimmer, free A cutter or motor chain saw can be used shaped handle at the end of a motor housing also in three different angular positions offset from each other by 90 ° adjustable and lockable in these. There is one for locking provided on the handle pawl provided with a Projection in a corresponding recess in the motor housing engages and that of a spring towards a lock position is charged.

The object of the invention is an improved elec power tool to create that the disadvantages of the prior art Avoids technology and an ergonomic way of working for one allows the widest possible working area.

This task is performed with a power tool according to the mentioned type according to the invention solved in that the handle part compared to the motor housing in at least four predetermined win kelppositionen rotatable and can be locked in this.

The object of the invention is completely ge in this way solves. According to the present in the prior art Overcome prejudice that it is made for all use cases sufficient is a rotatable handle part opposite the Motorge housing from a middle position into another working position to the left or to another working position to the right twist. According to the invention, another is now Working position allows in the handle part, for example, by 180 ° may be twisted relative to its normal position while two further working positions are possible, in which a ver  rotation from the normal position only by 90 ° clockwise in a sense or counter-clockwise.

This additional angular position makes work particularly difficult relieved especially on ceiling areas. Rough work on Dec Key areas occur, for example, in wagon construction. The win be held overhead to deburr parts or the like. Such work is significant according to the invention relieved, since the handle part by 180 ° compared to its normal position can be rotated. Further advantages are offered by stationary use of the angle grinder.

In an additional development of the invention is between the engine Housing and handle part a rotation angle limitation for limitation the maximum angle of rotation between the motor housing and the Handle part provided.

This measure prevents the handle part what can be rotated several times relative to the motor housing otherwise damage to the electrical connection lines between between the handle and the motor housing.

In an advantageous development of the invention, the handle has switch a handle button that locked against actuation is valid if the handle part is not in one of the pre level and locked to the motor housing is steady.

This prevents the power tool from being switched on if the handle is not in a stable position located in relation to the motor housing, so that an unintended  Rotate the handle part relative to the motor housing work and an associated risk of accidents is avoided.

According to a further embodiment of the invention is on the engine a central ring flange is provided in the radial out savings are provided in which a projection of a ver pivoted and featured in a locking position tensioned locking lever in one of the given Angular positions can be locked.

This results in a particularly simple arrest Possibility for the handle part in the specified angle positions on the motor housing, with a special space saving construction is realized. It is thus avoided that the handle can accidentally twist. Is a ver rotation of the handle part in a different angular position with respect desired on the motor housing, so rather must first Lock button are depressed, then the Handle part can be rotated relative to the motor housing until the lock button again at one of the specified angles positions in one of the radial recesses on the motor housing engages and the handle part against further rotation ge locked to the motor housing.

In an additional development of the invention is also on Handle part ver locking lever on a pivot axis pivoted, the first out as a push button depicted from the swivel axis in the direction of the motor housing has standing part, at the outer end of a projection is formed which in one of the recesses of the flange  is insertable, and one approximately at right angles to the first part has the second part projecting from the pivot axis, which with the handle button of the handle switch cooperates so that a Then press the handle button to switch on the motor is enabled if the pushbutton was previously pressed by pressing an activation position has been transferred so that the projection the locking lever in one of the radial recesses on Ring flange of the motor housing engages.

This way, using simple means, becomes an unintended one Start of the angle grinder when gripping the handle switch avoided. A user must first press the push button before he can press the handle button on the handle switch.

In an additional development of this version is the handle Ver button on the motor housing facing away from the end of the handle pivoted and against movement into an asset biased to turn on the engine, and points at its free end a web that is in a locked position if the pushbutton on a projection is not pressed in on the two strikes th part of the locking lever, so that an actuator the handle button to turn on the engine is prevented.

In an additional development of this version is the handle button against a spring force when the push button is pressed over the projection into the activation position for the scarf ten of the electric motor movable, the web on the Griffta interacts with the second part of the locking lever, to move the same from the activation position of the To prevent push button.  

This ensures that at the start of work Push button only needs to be pressed once and on closing after the handle switch has been operated, the Pushbutton remains in its activation position, so that results in a continuous operating position. Then the handle When the button is released, the locking lever releases the handle button again free, so that afterwards the pushbutton again must be pressed in before the handle switch is activated again can be fourth.

According to a further embodiment of the invention, the engine housing on its side facing the handle part a center len cylindrical pin with a passage for cable entry tion that penetrates the ring flange, with the handle part inwardly projecting webs are provided which on the Outside surface of the pin and in a space between the ring flange and an end face of the motor housing are.

This measure ensures good guidance of the grip part on Motor housing ensures and easy rotation ensured only low friction. Also becomes a simple one and cost-effective manufacturability guaranteed, in particular when the handle part on two assembled housing shells points.

In an additional development of the invention, the handle part no fan slots open.

This has the advantage that the sensitive handle switch is none Contamination due to penetrating dirt particles  is. Fan slots can instead be used, for example, in Mon door housing may be provided.

It is understood that the above and the following standing features to be explained not only in each specified combination, but also in other combinations or can be used alone, without the scope of to leave the present invention.

Embodiments of the invention are in the drawing are shown and are described in more detail in the following description explained. Show it:

Fig. 1 is a perspective view of a power tool according to the invention using the example of an angle grinder;

FIG. 2 shows a view of the power tool according to FIG. 1, on which only the end of the motor housing facing the handle part and the handle part can be seen, wherein one housing half of the handle part has been removed;

Fig. 3 is an exploded view of the right half of the housing of the handle part with locking button and associated spring, and the handle switch, which is mounted with the Ar locking lever to a unit;

Fig. 4 is a view of the motor housing from the handle part and

Fig. 5 is an exploded view of the motor housing with the front motor housing part, rear motor housing part and an insertion element for the rear motor housing part together with accessories.

In Fig. 1, an electric tool according to the invention is shown perspecti vically and generally designated by the number 10 . In the illustrated power tool 10 , it is egg NEN angle grinder, which is designed as a so-called two-hand angle grinder and has at its rear end a handle part designated overall with the number 25 , in which a handle switch is provided (see. Fig. 2). At the upper end of the handle part a push button 28 is provided, the function of which is explained in more detail below.

The power tool 10 further includes an overall designated with the Zif fer 22 motor housing, which has a front motor housing seteil 23 for receiving an electric motor 14 , and a rear motor housing part 24 , to which the handle part 25 connects. At the front motor housing part 23 , a gear housing 12 follows, in which a gear 16 is provided for driving a work spindle, which is only indicated schematically with the Zif fer 18 . On the left side of the Ge gear housing 12 , a receptacle 20 is also shown, into which a handle-shaped additional handle can be screwed so that the power tool 10 can be handled with a front hand on the accessory and with a rear hand on the handle part 25 . It is understood that on the opposite right side of the gear housing 12, a further receptacle for the additional handle is provided, so that the power tool 10 is suitable for a right-handed or a left-handed drive.

In Fig. 1, the protective hood seen in principle for an angle grinder is not shown for the sake of clarity.

The grip part 25 has a first, left grip housing part 26 and a second, right grip housing part 27 , the function of which will be explained in more detail below.

The handle part 25 can be rotated twice from the basic position shown in FIG. 1, in which the handle button 33 points downward according to FIG. 2, through an angle of 90 ° to the left, ie counterclockwise, and once from the position shown in FIG basic position shown. 1 to 90 °, ie twist to the right in a clockwise direction.

This twisting possibility enables a changeover between rough grinding, in which a surface is machined with a grinding wheel, and between cutting, in which a workpiece is severed with the end face of a cutting wheel. Furthermore, by the possibility of rotation of the handle part 25 by 2 × 90 ° in one direction, that is to say by 180 °, the handle switch can also be turned on the upper side of the power tool 10 . Such a handle position is particularly advantageous when working on rough grinding on ceilings and projections.

The rotation mechanism, which allows rotation of the handle part 25 relative to the motor housing 22 and locking in the pre-given angular positions, is described in more detail below with reference to FIGS . 2 to 4.

In Fig. 2, the handle part 25 together with the rear motor housing part 24 is shown in an enlarged view, the left handle housing part 26 being removed, so that the internal structure, which is shown somewhat simplified, can be seen.

The rear motor housing part 24 has an approximately circular cross section (cf. FIG. 4) and is cut off obliquely downwards at its front end, which can be joined together with the front motor housing part 23 , so that there is approximately an oblique truncated cone. On both sides of the rear engine housing set 24 a plurality of air intake slots 31 is laterally arranged one above the other and within the rear engine housing portion 24 at a short distance from the air intake 31 each have a baffle plate 30 , the end of which in Fig. 2 from the rear Motor housing part 24 can be seen protruding forward. The function of these baffle plates 30 is explained in more detail below.

The rear motor housing part 24 has a central cylindrical pin 44 , which protrudes into the handle part 25 . This pin 44 serves as a passage 62 (see. FIG. 4) to lead through electrical cable 50 between the motor housing and the handle part and also serves as a pivot bearing for rotatable on the handle part 25 on the rear motor housing part 24th The rear motor housing part 24 has an end face 21 facing the handle part 25 , with which an annular flange 42 is connected to form an intermediate space 51 via radially extending webs 29 . This ring flange 42 has a somewhat smaller outer diameter than the rear motor housing part 24 on its end face 21 , but has a significantly larger diameter than the pin 44 coaxial therewith.

The ring flange 42 has a total of four radial recesses 43 , which are each offset by an angle of 90 ° to one another (cf. FIG. 4).

At these recesses 43 , the grip part 25 can be locked with the aid of a locking lever 54 in the angular positions given by the recesses 43 with the rear motor housing part 24 .

Furthermore, a locking lever 38 is provided, which is pivotally received on a pivot axis 37 and as the first projecting from the pivot axis 37 forward in the direction of the transmission housing 12 has the push button 28 , at the front end of which a projection 41 is formed, which is aligned Alignment with a recess 43 can be inserted therein. The locking lever 38 also has a second, rigidly connected to the push button 28 portion approximately at right angles to protrude to the push button 28 downward and cooperating of the bottom at its end with the handle switch 32nd

The handle switch 32 has a handle button 33 , which is fixed at the lower rear end of the handle part 25 pivotable about a pivot axis 45 . The handle button 33 interacts with a switch module 34 , which is arranged above the handle button 33 , the handle button 33 being biased downwards by a spring 36 and moving upward against a switching pin 35 arranged on the underside of the switch module 34 for switching on - And switching off the electric motor 14 acts.

The handle button 33 has at its front, the rear motor housing part 24 facing end on the right and left side each an extension 59 , which are connected by a crossbar 46 at the outer end Ren, so that overall at the front end of the handle button 43rd an approximately rectangular recess is formed, in which the lower end of the second part 39 of the locking lever 38 is movable by a certain amount.

At its lower end, the second part 39 of the locking lever 38 has a projection 48 which serves as a stop for the crossbar 46 of the handle button 33 .

The locking lever 38 is biased by a spring 47 which acts on the second part 39 such that the Arretie approximately lever is acted upon 38 in the representation according to Fig. 2 in a clockwise direction, so that the pushbutton 28 provided to the top is clamped.

In the position shown in Fig. 2, the projection 41 of the push button 28 is aligned with one of the recesses 43 , so that the push button 28 could already be transferred by pressing into the illustrated activation position. By impressing the push button 28 , the handle button 33 with its cross bar 46 could be moved upward against the projection 48 of the second part 39 of the locking lever against the force of the spring 36 , so as to actuate the switch module 34 to the power tool 10 on.

Once this position is reached, the push button 28 can be released, since a pivoting back of the locking lever 38 under the action of the spring 47 from its activation position to its rest position is prevented by a front surface 49 of the second part 39 of the locking lever 38th strikes from the inside on the crossbar 46 of the handle button 33 .

This results in a continuous operating position, in which the handle button 33 must be kept single in order to enable constant working with the power tool 10 .

Is out of this in Fig. Position shown in Figure 2 now, the grip button is released 33, so the handle key 33 moves under the action of the spring 36 downward, so that their is moved past crosspiece 46 on the projection 48 of the second part 39 of the locking lever 38 and the locking lever 38 now pivots out of its activation position under the action of the spring 47 into its rest position or starting position. If this position is taken, the handle button 33 can no longer be moved upwards, since the crossbar 46 on the before jump 48 of the second part 39 of the locking lever 38 strikes.

If the motor is to be switched on, the pushbutton 28 must first be pressed, as a result of which the locking lever 38 according to FIG. 2 pivots counterclockwise, so that the handle button 33 with its crosspiece 46 swings past the jump 48 upwards can be to actuate the switch pin 35 of the switch module 34 .

In Fig. 2 is also at the lower end of the handle portion 25 of the locking lever 54 Ver recognizable, which is pivotally received with a receptacle 58 on egg ner pivot axis 55 of the second or right handle housing part 27 (see also Fig. 3). This locking lever 54 is pre-tensioned by a spring 56 such that when the grip part 25 is aligned with one of the radial recesses 43 with a projection 57 it engages in the relevant recess 43 on the rear motor housing part 24 and the grip part 25 thus prevents rotation against it rear engine housing part 24 locks.

The locking lever 54 has the effect that the handle part 25 can only be rotated with respect to the motor housing 22 if the locking lever 54 is pressed in a targeted manner. At closing the handle member 25 can be rotated until after a rotation of 90 ° or a multiple thereof the locking lever 54 is again aligned with a radial recess 43 of the ring flange 42 and the projection 57 of the locking lever 54 under the action of the spring 56 engages with its projection 57 in the radial recess 43 of the ring flange 42 and locks the grip part 25 against further rotation. The function of locking the grip part 25 in a r of the predetermined angular position on the motor housing 22 is decoupled in this way from the function of the pushbutton 28 , which serves as a switch-on lock against unintentional switching on of the electric motor, but uses the same radial recess 43 to latch like the locking lever 54 .

The grip part 25 is guided by webs 52 , 53 projecting inwards from both grip housing parts 26 , 27 on the pin 44 on the one hand and on the ring flange 42 on the other hand. As can be seen in FIG. 3, the right handle housing part 27 has two mutually parallel ring webs 52 , which effect a first guidance on the surface of the pin 44 , and furthermore, at its end facing the rear motor housing part 24, a plurality of ring web sections 53 running in the circumferential direction that engage in the space 51 between the end face 21 and the ring flange 42 .

Since the annular flange 42 is connected via individual radially extending ribs 29 to the end face 21 of the rear motor housing part 24 , this results in a reduced contact surface of the webs 53 and in connection with the parallel webs 52 which rest on the pin 44 , an extremely reliable rotation guide for the handle part 25 on the rear Mo torgehäuseteil 24 , but with a relatively low friction resistance.

Between the handle part 25 and the rear motor housing part 24 , a rotation angle limitation is also provided, which is formed by a projection 60 on the right handle housing part 27 (see FIG. 3) and by a radial rib 61 (see FIG. 4) on the rear motor housing part 24 which extends between the pin 44 and the outer edge of the ring flange 42 . This avoids that the grip part 25 can be rotated in one direction by 360 ° or more.

In Fig. 5, the front Mo torgehäuseteil 23 , the rear motor housing part 24 and an insertable into the rear motor housing part 24 insertable member 70 and accessories are shown in an exploded view and are explained in more detail below.

The front motor housing part 23 serves to accommodate the electric motor 14 . In contrast, in the rear motor housing part 24, the insertion element 70 is received, which consists of a base plate 72 which extends over the cross section of the motor housing part 24 and with which electronic components 74 for controlling the power tool 10 are cast, and on the left and right sides of which a baffle plate made of aluminum sheet 30 protrudes forward.

During operation of the power tool 10 , cooling air is drawn in via the air slots 31 on both sides of the rear motor housing part 24 , which initially strikes the baffle plates 30 arranged immediately behind the air intake slots 31 , which leads to the deflection of dust particles and other contaminants, which may occur when working in a heavily polluted environment. (The air exits through air slots (not shown) in the area of the gear housing 12 ). This arrangement has an advantageous effect on the life of the electric motor 14 . The baffle plates 30 are also simultaneously designed as a heat sink for individual electronic components 74 , so that they are additionally cooled by the air flow drawn in. This contributes to the operational safety of the electronic components 74 .

While in conventional angle grinders the air intake slots were previously located in the handle part 25 , ie in the immediate vicinity of the handle switch 32 , the air intake slots 31 are now provided in the rear motor housing part 24 in a more fluidic manner from the handle part 25 . The bushing 62 for the cables 50 , which are provided with a plug 68 for connection to corresponding pins 40 on the switch module 34 (see FIG. 3), are largely closed by the base plate 72 of the insert element 70 . In addition, an elastic sealing washer 76 is provided, which is plugged onto the cable 50 and is located together with the latter within the passage 62 of the pin 44 in order to additionally seal the latter even when the grip part 25 is rotated.

In this way it is avoided that contaminated air gets into the area of the handle switch 32 and thus prematurely impairs its function.

The fact that the motor housing 22 is formed in two parts with a front motor housing part 23 and a rear motor housing part 24 , the manufacture and assembly is considerably simplified ver. The insertion element 70 with the electronic components 74 and the baffle plates 30 is inserted into the rear motor housing part 24 , while the electric motor 14 is mounted in the front motor housing part 23 ; then both components th by screwing screws located in the rear motor housing part 24 screw holes 64 in screw receptacles 66 in the form of pins on the front motor housing part 23 firmly connected.

Claims (11)

1. Power tool, in particular angle grinder ( 10 ), with an elongated motor housing ( 22 ), in which an electric motor ( 14 ) is received, with a gear housing ( 12 ) at a first end of the motor housing ( 22 ) for receiving a gear ( 16 ) for driving a work spindle ( 18 ), and with a handle part ( 25 ) which is rotatably fixed at a second end ( 24 ) of the motor housing ( 22 ) and in which a handle switch ( 32 ) is arranged, characterized in that the handle part ( 25 ) relative to the motor housing ( 22 ) can be rotated and locked in at least 4 predetermined angular positions. 2. Power tool according to claim 1, characterized in that the given angular positions are each one Angles of 90 ° are offset from one another. 3. Power tool according to claim 2, characterized in that the handle part ( 25 ) can be rotated from a basic position in one direction by 90 ° and in an opposite direction by two 90 °. 4. Power tool according to one of the preceding claims, characterized in that between the motor housing ( 22 ) and the handle part ( 25 ) a rotation angle limitation ( 60 , 61 ) for loading limitation of the maximum rotation angle between the motor housing ( 22 ) and the handle part ( 25 ) is provided is. 5. Power tool according to one of the preceding claims, characterized in that the handle switch ( 32 ) has a handle button ( 33 ) which is locked against actuation when the handle part ( 25 ) is not in one of the predetermined angular positions and with the Motor housing ( 22 ) is locked. 6. Power tool according to claim 5, characterized in that a central ring flange ( 42 ) is provided on the motor housing ( 22 ), in the radial recesses ( 43 ) are hen, in which a projection ( 41 ) of a pivotally mounted and in a locking position preloaded locking lever ( 54 ) can be locked in one of the predetermined angular positions. 7. Power tool according to one of the preceding claims, characterized in that on the handle part ( 25 ) an arresting lever ( 38 ) on a pivot axis ( 37 ) is pivotally fixed, the first as a push button ( 28 ) formed from the pivot axis ( 37 ) has in the direction of the motor housing ( 22 ) projecting part, at the outer end of which a projection ( 41 ) is formed, which can be latched into one of the recesses ( 43 ) of the ring flange ( 42 ), and a second approximately at right angles to the first part from the pivot axis ( 37 ) protruding second part ( 39 ) which cooperates with the handle button ( 33 ) of the handle scarf age ( 32 ) such that pressing the handle button ( 33 ) to switch on the electric motor ( 14 ) is only possible, if the pushbutton ( 28 ) has previously been pushed into an activation position so that the projection ( 41 ) of the locking lever ( 38 ) into one of the radial recesses ( 43 ) engages on the ring flange ( 42 ) of the motor housing ( 22 ). 8. Power tool according to claim 7, characterized in that the handle button ( 33 ) on the motor housing ( 22 ), th end of the handle part ( 25 ) is pivotally fixed and pre-tensioned against movement into the activation position, and one at its free end Web ( 46 ), which strikes in a locked position when the push button ( 28 ) is not pressed against a projection ( 48 ) on the second part ( 39 ) of the locking lever ( 38 ), so that actuation of the handle button ( 33 ) to switch on the elec tromotors ( 14 ) is prevented. 9. Power tool according to claim 8, characterized in that when the push button ( 28 ) is pressed in a working position, the handle button ( 33 ) against a spring force on the projection ( 48 ) past in an activation position for switching on the electric motor ( 14 ) and that the web ( 46 ) on the handle button ( 33 ) cooperates with the second part ( 39 ) of the locking lever ( 38 ) to prevent movement of the same from the activation position of the push button ( 28 ). 10. Power tool according to one of the preceding claims, characterized in that the motor housing ( 22 ) on its ner the handle part ( 25 ) side facing a central cylindrical pin ( 44 ) with a passage ( 62 ) for Ka beldurchführung that the ring flange ( 42 ) passes through, and that on the handle part ( 25 ) inwardly projecting webs ( 52 , 53 ) are provided, the surface of the pin ( 44 ) on the outer surface and in an intermediate space ( 51 ) between the ring flange ( 42 ) and one Front ( 21 ) of the motor housing ( 22 ) are guided. 11. Power tool according to one of the preceding claims, characterized in that the handle part ( 25 ) has no fan slots.