WO2006045611A1

WO2006045611A1 - Module for an electric tool, in addition to an electric tool that is equipped with a module of this type

Info

Publication number: WO2006045611A1
Application number: PCT/EP2005/011527
Authority: WO
Inventors: Winfried Dettling
Original assignee: Kress-Elektrik Gmbh & Co. Elektromotorenfabrik
Priority date: 2004-10-27
Filing date: 2005-10-27
Publication date: 2006-05-04
Also published as: RU2007119551A; RU2360788C2; EP1814699B1; DE102004052329A1; CN101111350B; CN101111350A; EP1814699A1

Abstract

The invention relates to an electric tool and a module (1) for an electric tool, in particular an electric hand tool, such as a drill hammer with a chisel function, equipped with a module of this type. The module is configured as a synchronisation and switching unit that can be pre-assembled and is used for a rotary switch (12) that activates different operating modes. Said module comprises a locking element (3) that engages in a non-positive fit in a part that rotates in a fixed manner with a tool spindle (29), in addition to at least one switching plate (5, 6) with a guide curve (14, 15) for converting a rotational displacement of the rotary switch (12) into an axial displacement for activating different operating modes. The invention permits a simplified assembly of the electric tool.

Description

Assembly for a power tool and a power tool equipped with such a unit

The invention relates to a structural unit for a power tool according to the preamble of patent claim 1 and to a power tool equipped with such a structural unit according to patent claim 10.

It is generally known to design power tools, such as rotary hammers, for example, in such a way that they are constructed from building units. The individual units can be inexpensively prefabricated and assembled with a few assembly steps to the final product. Typical examples of such units are motor and gear units, which are used in prefabricated state in the housing shells of the tool. For power tools with a variety of functions, such as drill bits with chisel function, due to the complexity still requires a high assembly cost. Especially the setting of the different operating modes requires a high mechanical effort.

From DE 42 05 840 C2 a rotary hammer with chisel function is known in which different operating modes are switchable by means of a slide switch. In the known rotary hammer the chisel function is realized in that a driven gear rotatably fixed to the drill spindle is pushed axially into a locking position with a housing-fixed locking ver¬. In order to re lativieren the possibility of intermediate positions in which the teeth of the locking element are aligned with the teeth of the output gear so that the driven gear can not be brought into engagement with the locking element is provided in the known hammer drill that the locking teeth of the peeler initially rejuvenated and Then gradually widening are formed, so that the output gear of the rotary drive moves even for the gewünsch¬ th engagement in the locking element rightly.

From DE 195 45 260 Al a rotary hammer is known in which the different operating modes are switchable by means of a rotary switch, wherein the rotational movement of the rotary switch is converted via a switching plate in an axial movement. The switching plate is mounted displaceably in the housing and is moved over an eccentrically arranged on the rotary switch cams be¬. In order to block the drill spindle in the chiseling operation, in the known rotary hammer a locking plate fastened to the gear housing is provided, the toothed area of which, by engagement with the teeth of the driven gearwheel of the drill spindle, holds it against rotation. In a "Zahn¬ on-tooth position" between locking plate and Abtriebs¬ gear, the latter can not be moved into the locking position.

The invention has for its object to propose a structural unit for a power tool, is ensured by the simple assembly of the power tool.

Furthermore, the object underlying the invention is to propose a power tool, in particular electric hand tool such as hammer drill with chisel function, which is ein¬ fold to assemble.

These objects are achieved by the features of claims 1 and 10.

Advantageous embodiments of the invention are specified in the dependent claims. The invention is based on the idea of creating a preassemblable unit in the form of a synchronization and switching unit for a rotary knob for switching different operating modes, which on the one hand has a locking element with which a part rotating with the tool spindle, in particular the output gear, on the other hand with a switching plate with switching curve for converting a rotational movement of the rotary switch is provided in an axial movement to the circuit of different operating modes for the realization of a chisel. The installation of an electric tool, which according to the invention is equipped with this premounted structural unit, is considerably simplified compared to the assembly of known power tools, since the components, such as the locking element and the switching plates, are not screwed individually to the housing or into special guides in the housing must be used.

In order to move the shifters in the axial direction, eccentric cams are arranged on the rotary switch with respect to the axis of rotation of the rotary switch, which cooperate with the Schalt¬ curves of the shifters.

According to a preferred embodiment of the present invention, the locking element for the perception of the drill spindle lock in the chisel function is to be designed such that it meshes with a larger number of gear gaps of a driven gear on the drill spindle, for example over a quarter circle or a Eighth circle to secure the chisel position wear-free.

In an embodiment of the invention is advantageously provided that the assembly has two, preferably parallel to each other an¬ ordered, axially displaceable button, wherein a switching plate for connecting and disconnecting the percussion drive and a switching plate for the axial displacement of a Abtriebszahnra¬ is formed on the tool spindle. By the axial displacement of the output gear, the drill drive can be switched on and off by the driven gear is brought into engagement or out of engagement with the drive gear of a countershaft. At the same time, the output gear can be brought into engagement with the locking element via this Schalt¬, in order to realize the chisel function. Likewise, the output gear is movable with this switching plate in an axial position in which it is not in engagement with the drive gear of the countershaft and on the other hand is not yet locked by means of the locking element. In this so-called bit position search position, the desired angle of rotation of the bit can be selected, in which the output gear is to be blocked in a further switching position.

In a further development of the invention is advantageously provided that the unit comprises a guide rod, along which the locking element and at least one switching plate against each spring force are axially displaceable. Due to the fact that the locking element is not fixed in its position, but rather is arranged axially displaceable against a spring force, a synchronization device between output gear and locking element is created in a surprisingly simple and effective manner. In the event that during the axial movement of the locking element along the boring spindle into the locking position the teeth of the locking element should be aligned with the teeth of the drive gear, the locking element is displaced axially against the spring force. As soon as only minimal torque acts on the drill spindle when inserting percussion drive, it is slightly rotated, whereby the locking element with the locking teeth in the tooth gaps the output gear snaps. In this way, the rotary switch and forcibly guided in this direction Schalt¬ sheet can be switched through in the bit position (lock position), even if the output gear can not be brought into engagement with the locking element due to its angular position.

The installation of the assembly in a power tool can be done simply by the guide rod is taken with its two end in a respective bearing in the housing, in particular is locked.

The axial Federkraftbeaufschlagung at least one control panel also provides a synchronization device. If the output gear wheel can not be brought into engagement with the drive gear of a countershaft because of its angular position, the rotary switch can still be rotated into the corresponding position due to the design according to the invention. As soon as the rotary drive is switched on, the output gear wheel, due to the axial spring load, snaps into meshing engagement with the drive gear of the countershaft. In the same way, the connection and disconnection mechanism for the percussion drive can be synchronized if the switching plate provided for the circuit of the percussion drive is designed to be axially spring-loaded. As a result of the embodiment according to the invention, the shifters are forcibly guided only in one direction of movement, so that switching through the rotary knob is possible independently of the angular position of the toothed wheels or coupling elements relative to one another. The switching plate, which moves the output gear axially, should be loaded in such a manner that the driven gear is spring-loaded in the direction of the drive gear, so that the switching plate is positively driven out of the rotational drive position. The same applies to the switching plate, which is responsible for the connection and disconnection of the percussion drive. Also, this switching plate should be forced out only from the engaged position. For this purpose, it is advantageous if all springs of the assembly are arranged such that the Rich¬ direction of the spring force on the axially displaceable Arretierele¬ element and the spring force on at least one, preferably all, axially movable shifters are rectified.

The realization of the assembly with as few Einzel¬ share is possible, that the locking element and at least one switching plate in each case a coaxially arranged Schalt¬ rod spring, preferably coil spring, is assigned, each coil spring arranged with one end to one on the shift rod Stop, in particular a Si cherungsring supported. It is advantageous if the An¬ impact for a switching plate associated coil spring simultaneously forms an axial stop for the locking element and / or the stop for a switching plate associated coil spring simultaneously forms an axial stop for another switching plate.

Preferably, the locking teeth are arranged symmetrically with respect to a central axis which is perpendicular to a longitudinal axis of the guide rod. This ensures that the locking element is acted upon symmetrically with respect to the guide rod and can not be twisted or folded against it.

Preferably, a headband may be provided, which in the

Drilling the switch plate fixed and thus holds the drive gear in its position. This prevents that in the case of a shock load of the tool or a release the slip clutch, the output gear, which is otherwise held by the coil spring in position, can escape and disengage.

A particularly resilient and low-wear locking element according to the invention is obtained when the Arretierele¬ element by means of the metal injection molding method (MIM) is made. Here, metal powder is first mixed with plastic powder and injected into a mold, whereupon the plastic is baked.

The invention will be explained in more detail below with reference to the figures showing an exemplary embodiment.

Showing:

1 is a side view of the assembly with rotary switch,

2 a rotated with respect to FIG. 1 by 90 ° view of the unit,

3 is a perspective view of the front Teilbe¬ empire of a hammer drill in the switch position "drilling with impact drive" (drill hammers),

4 is a perspective view of the front Teilbe¬ empire of a hammer drill in the switch position "drilling without percussion drive",

5 is a perspective view of the front Teilbe¬ empire of a hammer drill in the switch position "chiselling" with locked drilling spindle, 6 is a perspective view of the front Teilbe¬ empire of a hammer drill in the switch position "chiselling" at a "tooth-on-tooth position"zwi¬'s output gear and locking element,

7 is a perspective view of the front Teilbe¬ empire of a hammer drill in the switch position "chisel position search" and

Fig. 8 assembly in the switch position "drilling" with zu¬ additional bracket

The structural unit 1 according to the invention consists of a guide rod 2 on which a locking element 3 with locking teeth 4, as well as a first switching plate 5 and a second switching plate 6 are mounted axially displaceably.

The guide rod 2 is guided for this purpose by an integrally formed with the locking element 3 bearing sleeve 7. The shifters 5, 6 are arranged parallel to each other and in each case via orthogonal to the shrouds 5, 6 aligned th tabs 8, 9, 10, 11 held captive and displaceable on the guide rod 2, wherein the guide rod 2 through a respective through hole in the tabs 8, 9, 10, 11 is guided. The second switching plate 6 is arranged between the first Schalt¬ plate 5 and a rotary knob 12, wherein the second switching plate is provided with a 90 ° angled and parallel to the guide rod 2 extending connecting plate 13 which engages over the first switching plate 5 and the second

Switch plate 6 with the tabs 10, 11 connects. In order to shorten the length of the structural unit 1, the tab 10 of the second th shift plate 6 between the tabs 8, 9 of the first shift plate on the guide rod 2 is arranged.

Each switching plate 5, β has a guide curve 14, 15, which cooperate with a respective transverse to the guide rod 2 extending cam 16, 17 of the rotary switch 12.

In the embodiment shown in Fig. 1, the first shift plate 5 is displaced against the spring force of a coil spring 18 on the guide rod 2 in the direction of locking element 3. The cam 17 is in the switch position shown not engaged with the associated guide cam 15. The shrouds 5, 6 are zwangsge¬ leads only in one axial direction.

The locking teeth 4 of the locking element 3 are arranged over a circular segment. In the embodiment shown in FIG. 1, the locking element 3 rests against a retaining ring 19, which is held in a groove of the guide rod 2 and forms an axial stop for the locking element 3. The securing ring 19 simultaneously forms a stop for the spiral spring 18 of the first switching plate 5, as a result of which the spiral spring 18 is supported on the securing ring 19 and on the lug 8.

The locking element 3 is associated with a coaxial with the guide rod 2 and the bearing sleeve 7 arranged coil spring 20 which is supported at one end to a held in a circumferential groove of the guide rod 2 retaining ring 21 and with its other end laterally on the locking element 3. For er¬ facilitated mounting of the assembly are on the locking element 3 two axially and parallel to the guide rod 2 extending Bolt 22, 23 provided, which can engage in corresponding recesses in the housing.

The second switching plate 6 is associated with a coil spring 24 which, like all coil springs 18, 20 coaxial with the guide rod 2 is arranged. The spiral spring 24 is supported on a circlip 25 held in a groove of the guide rod 2 and laterally on the lug 10 of the second switch plate 6. The securing ring 25 simultaneously forms an axial stop for the first switching plate 5. The axial stop for the second switching plate 6 is formed by a securing ring 26.

In FIGS. 3 to 7, only the partial area of a rotary hammer is shown in fragmentary form. On the Dar- position of the drive motor and on the representation of Gehäu¬ seteilen was omitted for reasons of clarity. The unillustrated drive motor is in a fixed rotary engagement with a countershaft 27 via a shaft 28, wherein the countershaft 27 causes both the rotary drive for the drill spindle 29 and the impact drive. The percussion drive is realized by means of a Taumella¬ designed in a conventional manner 30, which acts via a wobble finger on a Kol¬ ben a striking mechanism. The countershaft 27 is guided centrally through the swash bearing 30 and mounted rotatably with respect to this. The swash bearing 30 can be brought via a jaw clutch 31 in rotationally fixed engagement with the Vorgele¬ waves 27, as shown for example in Fig. 3. For this purpose, the dog clutch 31 has an axially displaceable on the countershaft 27 and rotationally fixed on this mounted coupling sleeve 32 with two axially projecting

Clutch cam 33 which can engage in corresponding grooves of a Kupp¬ lungsgegenstücks 35. The coupling piece 35 is rotatably connected to the swash bearing 30. The second switching plate 6 engages with the tab 10 in a um¬ running groove 36 of the coupling sleeve 32, whereby the second switching plate 6 and the coupling sleeve 32 of the dog clutch 31 can perform a coupled axial movement.

On the countershaft 27, a drive gear 37 is arranged rotatably, which meshes in Fig. 3 with a driven gear 38. The output gear 38 is rotatably mounted on the drill spindle 29. For safety reasons, however, a slip clutch 39 is provided in a known manner in order to avoid injuries when tilting the drill during the drilling operation. The slip clutch and thus the output gear 38 and the first shift plate 5 are coupled together in the axial direction. For this purpose, the first switching plate 5 engages with the tab 8 in a circumferential groove 40 of the slip clutch 39, so that the output gear 38 is indeed rotatable relative to the unit 1, but in the axial direction of movement is positively connected to the first switching plate.

About the rotary switch 12 and the unit 1 unter¬ different operating modes can be switched. The rotational movement of the rotary switch 12 is converted via the cams 16, 18 in conjunction with the guide curves 14, 15 into axial movements of the switching plates 5, 6 and thus of the driven gear 38 and the coupling sleeve 32 of the dog clutch 31.

In the following, the different operating modes are explained in more detail with reference to FIGS. 3 to 7.

The operating mode "drilling with impact drive" (rotary hammers) is shown in Fig. 3. The shifters 5, 6 abut with the tabs 8, 11 on the securing rings 25, 26, whereby the output gear 38 of the drill spindle 29 meshes with the drive gear 37 of the countershaft 27, which in turn transmits the rotary motion of the drive gear 37 via the output gear 38 to the drill spindle 29 (drilling). At the same time, the dog clutch 31 is closed. The coupling sleeve 32 engages with the coupling cam 33 in grooves of the Kupplungsge¬ genstücks of the swash bearing 30, whereby the rotational movement of the countershaft 27 is transmitted to the swash bearing 30, wo¬ by again a wobble finger acts on a percussion piston, not shown (hammering).

4, the rotary switch 12 is rotated into the switching position "bores", whereby the second switching plate 6 has been displaced axially against the spring force of the spring 24 on the guide bar 2 in the direction of the locking element 3, as compared to FIG. by the cam 17 having been moved along the guide curve 15. The coupling sleeve 32 forcibly coupled to the second shift plate has been displaced axially along the countershaft 27 in the direction of the drive gear 37, whereby the coupling cams 33 of the coupling sleeve 32 are disengaged from the grooves 36 of the coupling counterpart 35 Thus, the rotational movement of the countershaft 27 is no longer transmitted to the swash bearing 30, so that the percussion drive is deactivated.The axial position of the first shift plate 5 has not been changed compared to the operating mode shown in FIG. whereby the drive gear 37 continues to mesh with the output gear 38 of the drill spindle 29.

If now the rotary switch 12 is rotated back from the switching position shown in Fig. 4 by 90 ° in the Schalt¬ shown in Fig. 3 position, the second switching plate 6 due to the spring force of the spring 24 again axially in the position shown in Fig. 3 procedure, whereby the coupling 33 intervene in the grooves 34. If the case is that the coupling cams 33 should not be aligned with the grooves 34, the switch can still be rotated into the position shown in FIG. However, the second switching plate 6 moves only so far in the axial direction until the Schaltno¬ bridges 33 abut the coupling counterpart 35. However, as soon as the countershaft 27 is then driven, the clutch cams 33 snap into the grooves 34 due to the spring loading with the coil spring 24 into the grooves 36. The embodiment of the assembly 1 according to the invention thus creates a synchronization for the connection of the percussion drive.

In FIG. 5, the switch is moved to the "chiseling" position. In contrast to the operating mode shown in FIG. 3, only the first shift plate 5 has been displaced axially in the direction of the locking element 3 on the guide rod 2, as a result of which also the shift plate In this way, only the impact drive is activated, so that the output gear 38 no longer meshes with the drive wheel 37 of the countershaft 27, but with the locking teeth 4 of the locking element 3 The drill spindle 29 is prevented from rotating by the locking element 3.

Fig. 6 shows the same switch position as in Fig. 5. However, the output gear 38 could not be brought into engagement with the locking teeth 4 of the locking element 3, since the teeth of the output gear 38 and the locking teeth 4 were cursing in Fig.

5 axially displaced toward the front end of the drill spindle 29 of the output gear 38. In this case, the coil spring 20 has been compressed. Due to the axia- For example, it is only possible for the rotary switch to be rotatable in the rotational position shown in FIG. 6. Oh¬ ne displaceable mounting of the locking element 3, the axial movement of the output gear 38 and thus the Axialbe¬ movement of the switching plate 5 and the rotational movement of the rotary scarf 12 would be blocked. Due to the inventive design of the assembly 1, the locking element 3 is biased against Ab¬ drive gear 38, so that the locking teeth 4 of the locking member 3 snap into the tooth gaps of the driven gear 38 as soon as only a small rotation of the Bohrspin¬ del 29 takes place. Due to the resilient bias of the animal element Arre¬ thus a synchronization device for the locking mechanism is provided.

7, the rotary switch 12 is rotated into the "cutter position position." In this case, the first shift plate 5 has been displaced axially, to such an extent that the driven gear 38 is positioned in the axial direction between the drive gear 37 and the arresting element 3 In this position, the rotary drive is decoupled, however, the drill spindle 29 with the output gear 38 is manually rotatable so that the desired bit position can be searched before the rotary switch 12 is rotated by another 45 ° into the "bit position" shown in FIG "is twisted.

FIG. 8 shows a retaining clip 41, which is fastened to a housing flange 46 with a fastening leg 42. The retaining bar 41 has a securing leg 44 which engages around the switching plate 5 in a front contact area 45. In this position, it is thus ensured that the slip coupling 39 is held positively in position via the groove 40 with the leg 8 of the switching plate 5. Without such Retaining clip 41, the slip clutch 39 is held only kraft¬ conclusively on the coil spring 18 on the locking ring 25, so that in the case of a shock stress there is the risk that the driven gear 38 disengages. An increase in the spring force to reduce this Ge¬ separates, otherwise the switching forces are too high.

Upon actuation of the rotary switch 12 in a clockwise direction Maß view Fig. 8, the cam 16 runs on a Freigabeab¬ section 43 of the securing bracket 41 so that it dodge down and the switching plate 5 releases before the No¬ 16 cken in Contact with the leadership curve 14 is coming.

LIST OF REFERENCE NUMBERS

1 unit

2 guide rod 3 locking element

4 locking teeth

5 first switching plate

6 second switching plate

7 bearing sleeve 8 tab

9 tab

10 tab

11 tab

12 Rotary switch 13 Connecting link

14 guide curve

15 guide curve

16 cam

17 cam 18 spiral spring

19 retaining ring 20 spiral spring

21 circlip

22 bolts 23 bolts

24 spiral spring

25 Circlip 26 Circlip 27 Countershaft 28 Shaft

29 drilling spindle

30 swashbearers

31 dog clutch 32 coupling sleeve

33 clutch cams

34 grooves

35 Coupling counterpart 36 groove

37 Drive gear 38 Output gear

39 slide coupling

40 circumferential groove 41 headband

42 mounting legs

43 release section

44 securing legs

45 System area 46 Housing flange

Claims

claims

1. Assembly unit for a power tool, in particular electric hand tool such as hammer drill with chisel function, d a d e r c h e c ia n s that the

Assembly (1) as a preassembled synchronization and switching unit for a rotary switch (12) for switching different operating modes is executed and an Ar¬ retierelement (3) for positive engagement in a rotationally fixed with a tool spindle (29) rotating part and at least one switching plate (5 , 6) with a Füh¬ approximately curve (14, 15) for converting a rotational movement of the rotary switch (12) in an axial movement for switching different operating modes.

2. The assembly according to claim 1, characterized in that the locking element (3) has a plurality of locking teeth (4) extending over a circular segment.

3. Assembly according to one of the preceding claims, characterized in that the structural unit (1) has two, preferably parallel to each other an¬ ordered, axially displaceable switching plates (5, 6) up, wherein a switching plate (6) for connecting and disconnecting a Impact drive and a switching plate (5) for the axial displacement of a driven gear (38) on the Werkzeug¬ spindle (29) is formed.

4. Assembly according to one of the preceding claims, characterized in that the structural unit (1) comprises a guide rod (2) on which the locking element (3) and the at least one switching Sheet (5, 6) are held, wherein both the Arretierele¬ element (3), and the at least one switching plate (5, 6) against each spring force axially along the guide rod (2) are displaceable.

5. Assembly according to claim 4, characterized in that for Er¬ generation of the spring force springs (18, 20, 24) are arranged ange¬ such that the direction of the spring force on both the locking element (3) and on the at least one switching plate ( 5, 6) is the same direction.

6. Assembly according to one of the preceding claims, characterized in that the retainer retainer (3) and the at least one switching plate (5, 6) each coaxially to the guide rod (2) ange¬ arranged coil spring (18, 20, 24) is assigned wherein each spiral spring (18, 20, 24) is supported at one end on a stop (19, 21, 25) arranged on the guide rod (2), in particular a securing ring.

7. An assembly according to claim 6, wherein a stop (19) for the switching plate (5) associated spiral spring (18) at the same time forms an axial stop for the locking element (3).

8. Assembly according to one of claims 6 or 7, characterized in that the stop (25) for the switching plate (6) associated Spi¬ ralfeder (24) simultaneously forms an axial stop for the further switching plate (5).

9. Assembly according to one of the preceding claims, characterized in that the Ar¬ retierzähne (4) are arranged symmetrically with respect to a central axis which is perpendicular to a longitudinal axis of the guide rod (2).

10. Power tool, in particular electric hand tool such as hammer drill with chisel function, with a rotary switch for switching different operating modes, characterized in that the rotary switch (12) with a structural unit (1) according to one of the preceding claims is engaged to a rotational movement of the rotary switch (12) into an axial movement to switch different operating modes.

11. Power tool according to claim 10, characterized in that on the rotary switch (12) for each switching plate (56) a switching cam (16, 17) is provided, each along the guide curve (14, 15) of the switching plate (5, 6 ), wherein the switching plates (5, 6) and the Arretierele¬ element (3) are spring-loaded axially in the direction of rotary switch (12).

12. Power tool according to one of claims 10 or 11, characterized in that the rotary switch (12) is rotated in distributed over the circumference Schaltpo¬ tions, the operating modes drilling, drills, chisels and chisel position search are switchable.

13. Power tool according to one of claims 10 to 12, d a d u r c h e c e n e z e i c h e s that the rotary switch (12) in the switch positions releasably, in particular audible, engages.

14. Power tool according to one of claims 10 to 13, d a d u r c h e c e n e c e s in that the switching plate (5) can be axially fixed by means of a holding clip (41) which can be activated via the rotary switch (12).