CN1095237C

CN1095237C - Hand electric tool

Info

Publication number: CN1095237C
Application number: CN 99102581
Authority: CN
Inventors: C·格伯; T·迈尔; S·克勒; O·蔡特
Original assignee: Scintilla AG
Current assignee: Scintilla AG
Priority date: 1998-03-04
Filing date: 1999-03-03
Publication date: 2002-11-27
Anticipated expiration: 2019-03-03
Also published as: JP4536179B2; CN1227987A; GB2334911A; CH693405A5; GB9904278D0; GB2334911B; JPH11309677A; DE19809135A1

Abstract

A portable electric tool is provided with a tool spindle drivable by an electric motor, a torque coupling for transmitting the advancely prescribed maximum torque arranged in a transmission mechanism between the electric motor and tool spindle and a manual adjustment member 14 for adjusting a different torque step in the torque coupling. In order to change adjustment members machine by machine without changing a transmission gear required for adjustment, the adjustment member is divided to a switch ring 23 turnable around a machine axis for enforcing the adjusting function and a design ring for a manual turning operation combined with the switching ring relatively and unturnably.

Description

Electric hand-held power tool

The present invention relates to a kind of electric hand-held power tool.

In a kind of known electric hand-held power tool (DE 42 13291 A1) that is designed to thrust borer; torque clutch is as a kind of protectiveness clutch of the slip-clutch design that has a disc spring, so that machine and user are protected during cutter locking in boring procedure.The adjusting part that the different operating status adjustment is used can be realized gear shift and be converted to hammer or chisel operation from the percussion drill operation.

Well-known so-called storage battery electric screw wrench is to be adjusted to the torque that maximum allows by means of adjusting part to come tighten the screws, and torque adjustment can be carried out classification, and can be adjusted to a plurality of adjusting positions by the conversion of adjusting part.

The advantage of electric hand-held power tool of the present invention is, because adjusting part is divided into the outward appearance that a control ring of carrying out the transmission regulatory function and manual structure ring can change the adjusting part from a kind of machine to another kind of machine, does not need to change and regulate required transmission device.Control ring belongs to transmission device, and by the decision of requirement here, and to satisfy whole transmission types all be identical repertoire.Structure ring is born the function of whole variations, can't help transmission device decision, and can at any time load onto and change.Its outward appearance can be changed to another kind of machine to some extent by a kind of machine, the number of same adjusting position and also can change with respect to the position of the anglec of rotation of structure ring.Without structure ring, regulate transmission device and also have function completely, it is stepless at this moment having only torque adjustment.

According to a kind of preferred structure pattern of the present invention, a locking clutch is housed in torque clutch, this locking clutch is set up a kind of firm connection that is connected and composed by profile in direction of rotation between the clutch component of torque clutch.This locking clutch is engageable and disengagement by means of regulating element, and required for this reason controlled function is then carried out by a control ring.

According to a kind of favourable structural shape of the present invention, be provided with a percussion mechanism and axially drive cutter shaft or axially drive one by the shaft-driven cutter of cutter.This percussion mechanism is engageable and disengagement by means of an adjusting part, and required for this reason controlled function is then carried out by control ring.

These design features of electric hand-held power tool have such advantage, promptly with this control ring except carrying out the regulatory function of torque clutch, also can carry out the connection of certain operating state of electric hand-held power tool and other controlled function of disengagement, the operating state of " percussive drilling " and " boring " in a kind of composite type electric hand-held power tool that can be used as monkey wrench and boring bar tool for example, in these two kinds of operating states, torque clutch is all inoperative, but the locking clutch that is contained in the torque clutch is connected.This locking clutch is avoided can causing gear-box case to produce the axial force of very big load by the clutch transmission in drilling operation, and makes the clutch spring unloading of torque clutch, so torque clutch can reach a significantly long life-span;

According to a kind of favourable structural shape of the present invention, structure ring is designed to hood-shaped, and can fasten on the control ring.Wherein, be set with the position location in structure ring, these positions are corresponding with the adjusting position of the control ring of carrying out regulatory function and controlled function.Thereby mounting structure ring at any time, and do not need the instrument and the additional positioner that add, and can change afterwards.Can realize the different progression of torque adjustment, the different adjustment angle and the final position angle of level to level with identical adjusting transmission by setting different position locations.

Describe the present invention in detail below in conjunction with an embodiment shown in the drawings.Wherein:

Fig. 1 represents a kind of part longitudinal section of electric hand-held power tool;

The perspective view of an adjusting part of the electric hand-held power tool that Fig. 2 presentation graphs 1 part is cut open;

Two different perspective views of a structure ring of Fig. 3 presentation graphs 2 adjusting parts;

The perspective view of a retainer spring of Fig. 4 presentation graphs 2 adjusting parts;

Two different perspective views of a lid of Fig. 5 presentation graphs 2 adjusting parts;

The perspective view of a clutch of the electric hand-held power tool that Fig. 6 presentation graphs 1 part is cut open;

Fig. 7 represents to have the parts explosion of Fig. 6 clutch of the part of Fig. 2 adjusting part;

The perspective view of a clutch component of Fig. 8 presentation graphs 6 clutches;

Two different perspective views of another clutch component of Fig. 9 presentation graphs 6 clutches;

The perspective view that the part of Fig. 6 clutch was cut open when Figure 10 represented to have the part of Fig. 2 adjusting part;

Figure 11 represents that a locking of Figure 10 clutch carves two different perspective views of piece;

Figure 12 represents to have the perspective view that a kind of part of electric hand-held power tool of the conversion equipment of cutter shaft, gantry post and boring/percussive drilling conversion usefulness is cut open;

Figure 13 represents that Figure 12 holes/parts explosion of percussive drilling conversion equipment;

The parts explosion of cutter shaft and percussion mechanism when Figure 14 is illustrated in the percussive drilling operating state;

The electric screw spanner use that can be used as drilling machine, thrust borer and have adjustable torque with the part electric hand-held power tool shown in the longitudinal section among Fig. 1.A not shown motor is housed in 10 casings of representing, this motor is by cutter shaft 12 that is bearing in the main shaft bearing 36 of a transmission device 11 transmissions.These cutter shaft 12 1 ends are threaded axle journal 121, tighten a chuck on this axle journal, and this chuck is used for tightening drill bit, drill hammer or different helical tooth blades.Be provided with a torque clutch 13 in the driving-chain between motor and cutter shaft 12, but the transferable breakdown torque of this clutch is by means of the several levels of manual adjusting part 14 chosen in advance.In addition, this regulating element also has two other adjusting position that is used for regulating operating state " percussive drilling " and operating state " boring ".In these two kinds of operating states, clutch 13 rigid engagement, promptly inoperative as torque clutch, but as locking clutch work.

Clutch 13 has a bell housing 15 (Fig. 1,2,6,7,10,12), and the first clutch element 16 (Fig. 9) of an annular also can be fixed in antitorque ground with moving axially on shell.First clutch part 16 and the second clutch part that constitutes on the planetary internal gear 17 of transmission device 11 18 engagements, wherein the arc clutch projection 161 on the first clutch part 16 is between the clutch projection 181 of the inclination of second clutch part 18.In addition, second clutch part 18 also has clutch projection 182, and these clutch projections 182 are radially outward arranged far than clutch projection 181, and roughly radially in alignment with them.Clutch component 16 also has clutch projection 162, and they protrude from first clutch part 16 and deviate from the side of second clutch part 18, and first clutch part 16 is anchored on the bell housing 15 antitorquely.This bell housing 15 has external screw thread 151 (Fig. 7), can tighten an adjusting nut 19 up and down at this external screw thread.Clutch spring 20 of supporting between adjusting nut 19 and first clutch part 16, this spring is engaged to

clutch projection

161 and 181 on two

clutch components

16 and 18 by the power connection.Adjusting nut 19 moves far more by the direction that is rotated in external screw thread 151 upper edge first clutch parts 16, and the prestressing force of clutch spring 20 is big more, and the breakdown torque that is delivered on the cutter shaft 12 by torque clutch 13 is also big more.As long as be no more than the torque of adjusting on cutter, internal gear 17 is just locked, and the planetary gear 21 that is bearing on the planetary gear carrier 22 rolls on the internal tooth 171 of internal gear 17.Xuan Zhuan planetary gear carrier 22 transmission cutter shaft 12 thus.If the moment of reaction that acts on the cutter shaft 12 surpasses the torque of being regulated by clutch spring 20, then

clutch projection

161 and 181 is mutually in two clutch components 16 and the rotation of 18 next doors.The internal gear 17 of transmission device 11 is no longer locked like this, so planetary gear 21 no longer is bearing in transmission device 11 on the internal thread 171 of internal gear 17, is delivered on the cutter shaft 12 by planetary gear carrier 22 thereby no longer include torque.

As illustrated in fig. 1 and 2, adjusting part 14 has gear shift tooth cover 23 (Fig. 7), one and is overlapped on hood-shaped structure ring 24 (Fig. 3) on this gear shift tooth cover 23 and the lid 25 (Fig. 5) on end face that is buckled in bell housing 15, and this lid overlaps 23 the guiding and the axial positioning of rotating of structure ring 24 as the gear shift tooth.The lid 25 fixedly chucking hook of usefulness represents with 251 that in Fig. 5 and Fig. 2 the chucking hook that structure ring 24 is installed usefulness is then represented with 252.As can be seen from Figure 2, chucking hook 251 blocks the respective bump portion 152 of the back on the bell housing 15, and chucking hook 252 then snaps in the cannelure 245 on the structure ring 24.The voussoir of gearshift tooth cover 23 usefulness that carries out guiding movement on lid 25 embeds in the adjusting nut 19, so when 23 rotations of gear shift tooth cover, adjusting nut 19 rotates together, and is screwed under axially movable situation in the external screw thread 151 of bell housing 15.Gear shift tooth cover 23 and adjusting nut 19 be common to constitute a control ring, whole regulatory functions of torque clutch 13 and be contained in the engagement of the locking clutch in this torque clutch 13 and the connection of the controlling organization 30 that the controlled function of disengagement and are that wait to narrate, " percussive drilling " operating state is used and throw off and all undertaken by this control ring.Between lid 25 and bell housing 15, embed a retainer spring 26 (Fig. 4), prevent rotation and mobile.This retainer spring 26 has a positioning head 261, and the location notch 241 in this positioning head and the structure ring 24 interacts.The location and the number of the single adjusting position of the position of the location notch 241 on the structure ring 24 and number decision adjusting part 14.Structure ring 24 be fastened on the gear shift tooth cover 23 and with its antitorque connection.For this reason, in the corresponding groove 231 of the brace 242 on the inboard of structure ring (Fig. 3 B) embedding gear shift tooth cover 23 (Fig. 7).The clamping element that constitutes on the inboard of structure ring 24 243 embeds the gear shift teeth and overlaps in the lug boss 232 of the corresponding formation in back of 23 upsides (Fig. 2), and structure ring 24 axially is not fixed on the gear shift tooth cover 23 movably.

The order of the adjusting position of adjusting part 14 is such regulations: the different torque level of the torque clutch 13 of scalable " boring " operating state when for example the manual facility of scalable are used as the electric screw wrench in 15 adjusting positions that are arranged in order at remaining in scalable in first adjusting position " percussive drilling " operating state, second adjusting position below.Along with the continuous increase of the rotation of structure ring 24, the number of adjusting position also constantly increases, and at this moment the maximum torque transfer capacity of regulating in torque clutch 13 progressively increases.In the adjusting position of two fronts of structure ring 24, it is inoperative to change clutch 13, and locking clutch is connected, so clutch spring 20 unloads to a great extent.

For the rigid engagement of torque clutch 13 or in order to be contained in the connection of the locking clutch in the torque clutch 13, evenly distributing on the whole circumference of bell housing 15 is provided with a plurality of locking wedge blocks 27 that can axially carry out guiding movement, and they are locked at the clutch component (16) that is fixed on the bell housing (15) between the projection 162 antitorquely.Only see a locking wedge block 27 in Figure 10, this voussoir shows with two different views in Figure 11.As shown in figure 10, this locking wedge block 27 is exerted pressure by means of a convex annular race 29 that constitutes on gear shift tooth cover 23 that along the circumferential direction constantly rises in axially towards at the compression spring 28 of bell housing 15 upper supports.Compression spring 28 is pushed down the end face 271 (Figure 11 B) perpendicular to the moving direction of locking wedge block 27 like this, and by 23 supportings of an axle journal, other end 272 then is close on the cam path 29.Two

vertical faces

274 and 275 that are parallel to the extension of locking wedge block 27 moving directions of locking wedge block 27 are designed to binding face.In working order when " percussive drilling " and " boring ", in preceding two adjusting positions of structure ring 24, gear shift tooth cover 23 has such position of rotation, between promptly cam path 29 pushes clutch projection 182 on the second clutch part 18 with locking wedge block 27 towards compression spring 28.One of binding face 274,275 of locking wedge block 27 just is fitted in the face 182a or the 182b last (Fig. 8) of an extension vertically of cover 182 like this, and sets up a firm connection that is connected to form by profile purely between two clutch parts 16,18.Evenly distribute on whole circumference when a plurality of locking wedge block 27 is set, each voussoir 27 all is bearing on the independent cam path 29, and cam path 29 then is arranged on gear shift tooth cover 23 on the end face of clutch 13 mutually with one heart with certain radial distance.If structure ring 24 continues rotation when exceeding preceding two adjusting positions, cam path 29 is stepped back, locking wedge block 27 then withdraws from from second clutch component 18 again by compression spring 28, at this moment torque clutch 13 generation effects, the breakdown torque that it transmits is by the prestressing force decision of clutch spring 20.

When " percussive drilling " operating state, cutter shaft 12 also produces an ascending motion with very little axial stroke except that it rotatablely moves.For this reason, the ratchet that constitutes percussion mechanism 30 has two ratchet member 31,32 (Fig. 1 and Figure 14), and wherein, first ratchet member 31 is rigidly connected with cutter shaft 12, and second ratchet member 32 is fixed in the bell housing 15 then antitorquely He axially movably.A compression spring 33 is fixed on second ratchet member 32 on the backstop 34 of bell housing 15.Two

ratchet member

31,32 of the percussion mechanism of seeing in Figure 14 parts explosion 30 keep engagement by compression spring 33 and another its opposed facing ratchet teeth portion of stage clip 35 usefulness that is bearing between tool spindle 19 and the main shaft bearing 36.When rotated, the axial stroke of cutter shaft 12 effects is decided by the axial height of ratchet teeth portion.When structure ring 24 was positioned at its first adjusting position, these two ratchet member, 31,32 ratchet teeth portions by them were meshing with each other, so percussion mechanism 30 is connected.When structure ring 24 rotated to its next adjusting position, then moving jaws 37 just promoted (Fig. 1 is right-hand) far away like this with cutter shaft 12, two

ratchet member

31,32 was thrown off, as shown in Figure 1.When cutter shaft 12 moved, second ratchet member 32 fitted on the backstop 34 of bell housing 15 under the elastic force effect of compression spring 33, so it can not moving and moving with first ratchet member 31 with cutter shaft 12.This percussion mechanism 30 is thrown off.Cutter shaft 12 produces pure rotatablely moving.

For the purpose of clear, only moving jaws 37 is illustrated as construction unit among Fig. 1, this construction unit can be found out from parts explosion 13.It comprises a bearer ring 38, and main shaft bearing 36 connects in this bearer ring of packing into by profile, and is pressed onto the bearer ring bottom by holddown spring 35; Also comprise a crescent moon ring 39, this crescent moon ring 39 is contained on the bell housing 15 antitorquely; And comprise a connecting ring 40, and the bow-shaped section 401 overlap joint crescent moon rings 39 on these connecting ring 40 usefulness circumference, they are contained in the gear shift tooth cover 23 by the profile connection, and set up an antitorque connection between gear shift tooth cover 23 and connecting ring 40.Crescent moon ring 39 has two rising ramps 41 at it on the end face of connecting ring 40, these two rising ramps are arranged in the circumferencial direction at a certain distance mutually.Each rising ramp 41 is looked gradually from the circumferencial direction of crescent moon ring 39 ring surfaces and is raise and reduce gradually again towards the ring surface direction.The connecting ring 40 that the plane is fitted on the annulus area of crescent moon ring 39 has a groove 42 in the scope of each rising ramp 41, the length of groove 42 is greater than the length on inclined-plane.Three hooks 43 that are staggeredly arranged with the same circumference angle of bearer ring 38 usefulness hook the connecting ring 40 from the end face of crescent moon ring 39.Wherein, hook 43 is fixed on bearer ring 38 in the crescent moon ring 39 simultaneously antitorquely.

Figure 12 represents the perspective view of the moving jaws of a composition.In shown position, rising ramp 41 stretches in the connecting ring 40 by groove 42 on crescent moon ring 39, and connecting ring 40 then plane fits on the crescent moon ring 39.As previously mentioned, cutter shaft 12 promotes far away like this along Fig. 1 left by holddown spring 35,

ratchet member

31,32 is meshing with each other and second ratchet member 32 rises from backstop 34.Like this, " percussive drilling " operating state is connected, and the corresponding position of rotation by gear shift tooth cover 23 is connected locking clutch simultaneously.When structure ring 24 forwarded its second adjusting position to, connecting ring 40 moved on on the rising ramp 41, and bearer ring 38 moves axially by one of the elastic force generation of hook 43 towards compression spring 35 simultaneously.The main shaft bearing 36 that is bearing in (Fig. 1) on the shoulder 122 of cutter shaft 12 promotes cutter shaft and moves to Fig. 1 is right-hand.The distance that moves axially by the decision of the axial height of rising ramp 41 is to determine like this,

ratchet member

31,32 is thrown off, and second ratchet member 32 is fitted on the backstop 34." boring " operating state is to regulate like this, and the corresponding turned position by gear shift tooth cover 23 makes locking clutch keep connecting.When structure ring 24 when this second adjusting position is rotated further other adjusting position, the adjustable ring 40 of Zhuan Donging no longer may leave rising ramp 41 together, so in whole other position of rotation of structure ring 24, percussion mechanism 30 is all inoperative.In this rotating range, constitute cam path 29 like this on gear shift tooth cover 23 simultaneously, promptly locking wedge block 27 withdraws from second clutch part 18 again by its compression spring 28, so locking clutch is thrown off, torque clutch 13 works.

The invention is not restricted to the embodiments described, and for example putting in order of the adjusting position of the adjusting part 14 of operating state " percussive drilling ", " boring " and torque preliminary election is not unmodifiable.Under the situation of other suitable structural shape of moving jaws 37, the adjusting position of operating state " percussive drilling " and " boring " can switch.These two adjusting positions also need not be positioned at before the adjusting position group of torque preliminary election, though this to clutch spring 20 to be discharged in these two kinds of operating states all be favourable.If stand certain clutch spring load, then for example also can between the torque adjustment set of locations, insert other adjusting positions of operating state " boring " and/or " percussive drilling ", thereby can reach the short conversion stroke of adjusting part 14.

Claims

1. electric hand-held power tool has the torque clutch that is used for transmitting the breakdown torque that can be scheduled to (13) that is provided with in the cutter shaft (12) of an electric-motor drive, the driving-chain between motor and cutter shaft (12) and one different torque classifications in this torque clutch (13) and regulates the manual adjustments assembly (14) of usefulness, it is characterized in that adjusting part (14) has one and carries out a control ring (19,23) and a structure ring (24) with the antitorque rotary manipulation by hand that is connected of this control ring regulatory function, that can rotate around machine shaft; And be contained in locking clutch in the torque clutch (13) have that at least one is fixed in the clutch component (16) can axially movable locking wedge block (27), this locking wedge block stretches between the clutch projection (182) that is arranged on the second clutch part (18) like this by moving axially, and the binding face that extends (274,275,182a, 182b) is fitted on locking wedge block (27) and the clutch projection (182) mutually; On gear shift tooth cover (23), constitute a cam path (29) that constantly rise vertically and that along the circumferential direction extend at least, at least one locking wedge block (27) with an end face (272) perpendicular to binding face (274,275) extension at elastic force effect lower support on this cam path.

2. by the electric hand-held power tool of claim 1, it is characterized in that: be provided with a percussion mechanism (30) and come axial transmission cutter shaft 12 or axial cutter of transmission by cutter shaft (12) transmission; This percussion mechanism (30) is engageable and disengagement by means of adjusting part (14); For the connection of this percussion mechanism (30) and the controlled function of disengagement have disposed control ring (19,23).

3. by the handheld electric tool machine of claim 1, it is characterized in that structure ring (24) is designed to hood-shaped, and can fasten on the control ring (19,23).

4. by the electric hand-held power tool of claim 1 or 3, it is characterized in that structure ring (24) has the position location, these positions are corresponding with the adjusting position of the control ring (19,23) of carrying out regulatory function and controlled function.

5. press the electric hand-held power tool of claim 4, it is characterized in that, the position location of structure ring (24) is by being fixed on the inboard of structure ring (24) at the location notch (241) that is provided with that evenly distributes on its whole circumference, they and a fixing retainer spring (26) acting in conjunction.

6. by the electric hand-held power tool of claim 1, it is characterized in that: control ring has a gear shift tooth cover (23) and an adjusting nut (19), and their antitorque ground also axially can interconnect with relatively moving; Hood-shaped structure ring (24) preferably clamps gear shift tooth cover (23) fully and firmly fastens to this gear shift tooth and puts.

7. by the hand-hold type electricity association toolroom machine of claim 6, it is characterized in that: torque clutch (13) has a bell housing (15) and two clutch components that firmly mesh together by a clutch spring (20) (16,18); The available screw thread of adjusting nut (19) is screwed on the bell housing (15), and this clutch spring (20) is bearing in the antitorque ground of this adjusting nut (19) and one and can be fixed between the clutch component (16) on the bell housing (15) with moving axially.

8. by the electric hand-held power tool of claim 7, it is characterized in that, fix a lid (25) on bell housing (15), cover at this, gear shift tooth cover (23) can carry out guiding movement, and hood-shaped structure ring (24) rotatably firmly fastens.

9. press the electric hand-held power tool of claim 8, it is characterized in that, retainer spring (26) is fixed between bell housing (15) and the lid (25), preventing rotation and to move, and with in the location notch (241) on a positioning head (261) the insert structure ring (24).

10. by the electric hand-held power tool of claim 1, it is characterized in that, compress spring (28) in one of the supporting between the end face (271) of this cam path (29) and bell housing (15) of the face of at least one locking wedge block (27).

11. electric hand-held power tool by claim 1 or 10, it is characterized in that, on this gear shift tooth cover (23), constitute a cam path (29) at least like this, promptly in the predetermined rotation angle range of the gear shift tooth cover (23) between the position location, two front and back of structure ring (24), at least one voussoir (27) fits on this cam path in the scope at the axial top of cam path (29).

12. by the electric hand-held power tool of claim 1, it is characterized in that: preferably evenly distributing on the whole circumference of the clutch component (16,18) of torque clutch (13) is provided with a plurality of locking wedge blocks (27); Each locking wedge block (27) is fitted on the independent cam path (29); These cam paths (29) are arranged on gear shift tooth cover (23) on the end face of clutch component (16,18) mutually with one heart with certain radial distance.

13. electric hand-held power tool by claim 2, it is characterized in that: percussion mechanism (30) have one non-rotary and can move axially second ratchet member (32) of setting with rigidly connected first ratchet member of cutter shaft (12) (31) and one, their ratchet teeth portion is meshing with each other by the elastic force that acts on this ratchet member (31,32); Gear shift tooth cover (23) is designed in the scope of an anglec of rotation, and moving axially of its caused cutter shaft (12) can make two ratchet member (31,32) throw off.

14. electric hand-held power tool by claim 13, it is characterized in that, the main shaft bearing (36) of supporting cutter shaft (12) inserts in the bearer ring (38), this bearer ring also can be provided with respect to the antitorque ground of bell housing (15) with moving axially, and in the angle range of gear shift tooth cover (23), produce an axial stroke that ratchet member (31,32) is thrown off, at this moment an axially movable ratchet member (32) that is loaded by a compression spring (33) is bearing on the backstop (34).

15. the electric hand-held power tool by claim 4 is characterized in that main shaft bearing (36) firmly is fastened on the bottom of bearer ring (38) by a holddown spring (35) that is bearing on the cutter shaft (12).

16. electric hand-held power tool by claim 15, it is characterized in that: go up at this bell housing (15) a crescent moon ring (39) is housed antitorquely, this crescent moon ring will have two rising ramps (41) that are arranged on the axial protrusion in the circumferencial direction at a certain distance mutually at it on the ring surface of bearer ring (38), this rising ramp along the circumferential direction begins to rise and descend again towards ring surface from ring surface respectively; On the end face of this crescent moon ring (39), fit one with the antitorque connecting ring that is connected of gear shift tooth cover (23) (40), in the scope of each rising ramp (41), this connecting ring all has a groove (42), the length of this groove (42) is greater than the length on this inclined-plane; This connecting ring (40) deviates from the end face of crescent moon ring (39) at it and is blocked by at least two hooks (43) that are arranged on mutually on the bearer ring (38) with the same circumference angle, and this hook is fixed on bearer ring (38) in the crescent moon ring (39) simultaneously antitorquely.