EP2529844B1 - Rotation atomiser with a spray body - Google Patents

Description

The invention relates to a spray-off body of a rotary atomizer for a coating machine with a spray body for the coating material which rotates during the coating and which can be mounted on the shaft of a drive motor. Furthermore, the invention relates to the particular bell-shaped Absprühkörper and the drive shaft of such a rotary atomizer.

Serving as Absprühkörper bell cup of known and customary for automatic series coating of workpieces rotary atomizer ( DE 43 06 799 ) have an externally threaded cylindrical hub part, which is screwed by hand into the open front end of the hollow shaft of the existing of an air turbine drive motor and can be unscrewed, for example, for maintenance or replacement for a new bell cup, the hollow shaft is suitably locked ( EP 1 245 290 ). Since for this releasable fastening device due to the high speeds of the air turbine, for example, in the order of more than 50,000 rev / min accurate centering and balancing of the bell cup with respect to the hollow shaft axis is important, the hub part of the bell cup has a conical part, which leads to the formation of a Centering cone bears against a corresponding conical region of the inner wall of the hollow shaft. In other known rotary atomizers ( EP 1 266 695 ), conversely, the hub part of the bell cup has an internal thread with which it can be moved to an external thread at the end of the hollow shaft.

US5685495 discloses a spray body which is attached to the spindle by centrifugal forces.

In addition to centering and balancing, the means for attaching a bell cup to its drive shaft must satisfy other conditions such as tight fit for reliable transmission of torques in both directions of rotation during acceleration or deceleration, small footprint, low risk of contamination e.g. through paint mist and easy cleaning and last but not least the possibility of quick and easy assembly and disassembly.

In the known Rotationszerstäubern there is the problem that the releasable fastening device can solve accidentally accidentally by itself. Such accidents can have different causes, such as Wear of the turbine, damage caused by collision of the bell cup with the workpiece to be coated or by improper handling, unbalance of the bell cup due to damage, by incorrect screwing or by contamination, etc. and in each case to a sudden sharp braking or locking of the shaft. The risk of accidental loosening of the bell cup can in the case of a screwed or screwed bell cup depending on the direction of the thread (right or left) even with strong acceleration of the bell plate exist. In any case, rotating at high speed, due to its kinetic energy automatically unscrewing bell cup can be thrown off the atomizer with the result of considerable damage and accident hazards.

In order to prevent the dangerous centrifuging of the bell plate, according to the already mentioned EP 1 266 695 the bell cup to be intercepted by unintentional loosening of the screw of radial housing projections, against which the detached bell plate abuts with radial projections of its hub part. The housing and Glockenentellervorsge can be twisted in a bayonet so against each other, that The bell cup can be removed by hand from the atomizer and inserted into it. Since in this construction, the automatic complete loosening of the screw connection is not prevented, the dissolved bell cup due to its usually still considerable kinetic energy and imbalance forces not only damage the screw thread, but also damage or destroy other parts of the bell cup itself and the atomizer.

The aim of the invention is to connect the bell cup or other rotating Absprühkörper of Rotationszerstäubern, especially of modern high-rotation atomizers with particularly powerful drive turbines, so with the drive shaft, that on the one hand the Absprühkörper relatively quickly and easily assembled and disassembled, on the other hand, but the dangers explained Blocking the shaft or other strong speed changes are avoided.

This object is solved by the features of the claims.

By the invention can be reliably avoided in a simple manner completely or at least in a sufficient to avoid damage measure an unwanted release of fasteners that meet the above-mentioned conditions such as the formation of a Zentrierkegels, but in itself would be uncertain, as for example in the screw connections of conventional atomizer is the case, the benefits of which can be maintained in principle in embodiments of the invention. The invention is not limited to embodiments with screw connections. Inventive means or measures to prevent the unwanted self-loosening of the fastening device or at least By based on imbalance forces considerable movements of Absprühkörpers radially to the rotation axis can be realized rather in very different ways, as will be explained by the embodiments described below with reference to the drawing.

The invention relates to a Absprühkörper a Rotationszerstäubers for a coating machine with a rotating during the coating spray body for the coating material, which is mounted on the shaft of a drive motor, and with a releasable attachment means for achsgleichen connection of a cylindrical and / or conical connecting part of Absprühkörpers with the drive shaft ,

Fixing elements are provided which prevent an automatic complete release of the fastening device when braking or accelerating the Absprühkörpers or at least unwanted movements of Absprühkörpers radially to the rotation axis, while they are rendered inoperative at standstill of Absprühkörpers to allow the release of the fastening device.

The spray body may be attached to the drive shaft e.g. be fastened or fastened by a shrink connection, which is solvable by heating.

It is possible that the connecting part of the Absprühkörpers and the drive shaft with mounted Absprühkörper radially abut each other, wherein the one element, the inner part and the other element forms the outer part, and that at least some axially coinciding locations of the outer diameter of the inner part in dissolved connection in the non heated state is greater than the inner diameter of the outer part.

The Absprühkörper can be locked or locked in particular by a on the one hand on the Absprühkörper and on the other hand on the drive shaft directly or via an intermediate element engaging union nut.

It is possible that the union nut is screwed onto or into the drive shaft and engages a radial projection of the Absprühkörpers or a fixedly connected to the Absprühkörper part.

The union nut may e.g. be bolted to a part of the Absprühkörpers or a fixedly connected part, and a locking member may be provided which engages in the union nut and / or the drive shaft to prevent relative axial movement between the union nut and the drive shaft.

It is possible that when mounted Absprühkörper the nut presses a at the end of the drive shaft axially projecting from this elastic clamp assembly with an axial force component against a stop surface of Absprühkörpers.

Furthermore, it is possible that a stop construction is provided which prevents unwanted axial relative movements between the Absprühkörper and the drive shaft after release of the fastening device and forms a guide for the Absprühkörper to prevent relative radial movement between the Absprühkörper and the drive shaft.

The Absprühkörper can be attached to the drive shaft, for example by a screw, after their release, the elements of the stop construction abut against each other.

The Absprühkörper can be attached to the drive shaft preferably by a screw connection, wherein the drive shaft or a component attached to it and / or the Absprühkörper or attached to him ring body have two spaced apart by an axial distance threaded.

It is possible that the thread facing the spray-off body has a larger diameter than the thread facing away from the spray-off body. Alternatively or additionally, of the axially spaced threads, one may be a right-hand thread and the other a left-hand thread.

Preferably, of the two axially spaced threads when the spray-off body is mounted, only one thread is engaged with a mating thread.

It is possible that the stop elements are formed by threaded elements and / or by radial projections of the Absprühkörpers or attached to it ring body and / or the drive shaft.

Preferably, the one stop element is formed by an inserted into an annular groove of the drive shaft resilient mold ring and the other stop element by an axially guided by the drive shaft radial projection of Absprühkörpers or attached to it annular body.

The Absprühkörper can be fixed in particular by an arranged between the drive shaft and a seated on or in the shaft coupling element O-ring on the shaft, wherein the union element can be releasably secured to the drive shaft and / or on the Absprühkörper.

It is possible that the coupling element presses a clamp arrangement connected to the drive shaft against a stop face of the spray-off body.

The spray-off body can preferably be fixed on the shaft by means of a snap ring arranged between the drive shaft and a ring element connected to the spray-off body.

It is possible that the connecting part of the Absprühkörpers is slidably and rotatably guided on or in the drive shaft or on a component attached to it, and that the Absprühkörper is connected to the shaft by a bayonet fitting or connectable.

The bayonet lock can in particular be formed by one or more pins mounted on the drive shaft or a component fastened to it or on the spray-off body or a component fastened to it and guided in mold slots of the spray-off body or shaft.

The pin (s) may e.g. are pressed axially against a stop end of the mold slot by a spring mounted in the drive shaft or a component attached to it.

Preferably, the pin (s) are clamped in the forming slot by a spring element formed by an integrally formed part of the shaft itself or a cylindrical member fixed to the shaft.

The pin can be locked in particular in the form of slot by a lock construction, the at least one Lock pin contains radially protruding from a relative to the drive shaft displaceable and / or rotatable ring member engages in an additional mold slot or engages a member which presses against the pin to be locked.

It is possible that the Absprühkörper is fixed by screwing in or on the drive shaft, and that the Absprühkörper and the drive shaft are provided with axially engageable locking means.

Preferably, the drive shaft is provided with axially displaceably mounted against the force of a spring device ratchet teeth.

It is also possible that the Absprühkörper is fixed by screwing in or on the drive shaft, that the connecting part and the drive shaft on the Absprühkörper facing side of the thread of the screw each containing an annular groove, the grooves are radially aligned with each Absprühkörper mounted and are each limited by radially extending abutment surfaces, and that in the annular gap formed by the grooves, a locking ring is inserted or used, which is so dimensioned and arranged that it prevents unwanted loosening of the screw from the Absprühelement against the abutment surfaces of the two annular grooves is pressed.

Preferably, the outer diameter of the locking ring is increased by the rotation. Alternatively or additionally, the securing ring may be a ring body cut through a slot.

It is possible that the spray-off body is fastened by screwing in or on the drive shaft, that the thread of the hollow cylindrical connection part of the spray-off body or the thread of the hollow drive shaft is divided by axially extending slots into a number of radially resilient segments distributed about the rotation axis, and that on the inside of the segments, a slit-sealing preferably rubber-elastic annular body is inserted.

The ring body may e.g. be formed in the slots engaging webs.

Preferably, the Absprühkörper is fixed by screwing in or on the drive shaft, wherein the bisector of the flank angle of the two screwed together thread is inclined against a perpendicular to the axis of rotation radial plane, so that the one flank surface is greater than the opposite other flank surface.

In particular, the angle of inclination of the bisector against the radial plane may be approximately between 5 ° and 25 °.

It is possible that the connecting part of the Absprühkörpers in or on the drive shaft is set or can be placed so that they form inner and outer elements, wherein in the outer side of the inner member one or more radially movable fixing elements are arranged in the rotating Absprühkörper by the Centrifugal force are pressed into radially adjacent recesses of the outer member and thereby prevent an axial relative movement of the inner and outer elements.

The fixing elements may be spherical, for example.

It is possible that an HSK holder of the spray-off body is provided in or on the shaft.

The spray body may e.g. consist of an outer part and a non-detachably connected to him hub part, wherein the hub part is connected to the shaft and the outer part is mounted on the outer periphery of the hub part.

The outer part may e.g. be fixed by welding on the hub part.

The invention relates to a spray body of a rotary atomizer as described herein.

The invention further relates to a drive shaft for a rotary atomizer with a spray-off body according to one of the claims.

• Fig. 1 die Befestigungseinrichtung eines Glockentellers gemäß einer Ausführungsform, die nicht Teil der Erfindung ist.
• Fig. 2 ein Ausführungsbeispiel, das nicht Teil der Erfindung ist, mit einer Überwurfmutter zur Arretierung des Glockentellers;
• Fig. 3A ein weiteres Ausführungsbeispiel mit einer Überwurfmutter, das nicht Teil der Erfindung ist;
• Fig. 3B einen Schnitt durch Fig. 3A längs der Ebene 3B-3B;
• Fig. 4 ein anderes Ausführungsbeispiel mit einer Überwurfmutter, das nicht Teil der Erfindung ist;
• Fig. 5A ein Ausführungsbeispiel mit einem Doppelgewinde, das nicht Teil der Erfindung ist;
• Fig. 5B eine Abwandlung des Ausführungsbeispiels nach Fig. 5A;
• Fig. 6 ein anderes Ausführungsbeispiel mit einem Doppelgewinde, das nicht Teil der Erfindung ist;
• Fig. 7A ein Ausführungsbeispiel mit einem den Glockenteller in der Hohlwelle arretierenden Federformring;
• Fig. 7B einen Schnitt durch Fig. 7A längs der Ebene 7B-7B;
• Fig. 8 ein Ausführungsbeispiel der Erfindung mit einem O-Ring, das nicht Teil der Erfindung ist;
• Fig. 9 ein weiteres Ausführungsbeispiel mit einem O-Ring, das nicht Teil der Erfindung ist;
• Fig. 10 ein Ausführungsbeispiel der Erfindung mit einem Sprengring, das nicht Teil der Erfindung ist;
• Fig. 11 ein weiteres Ausführungsbeispiel mit einem Sprengring, das nicht Teil der Erfindung ist;
• Fig. 12 eine nicht beanspruchte Ausführungsform mit einem Bajonettverschluss in drei Darstellungen;
• Fig. 13 eine nicht beanspruchte Ausführungsform mit einem Bajonettverschluss und einer zusätzlichen Schlosskonstruktion in vier Darstellungen;
• Fig. 14 eine nicht beanspruchte Ausführungsform mit einem BajonettVerschluss in zwei Darstellungen;
• Fig. 15 eine Abwandlung des Ausführungsbeispiels nach Fig. 14 mit einer Schlosskonstruktion in drei Darstellungen;
• Fig. 16 eine nicht beanspruchte Ausführungsform mit einer axial wirkenden Rastsicherung in drei Darstellungen;
• Fig. 17 ein weiteres, durch einen Sicherungsring gekennzeichnetes Ausführungsbeispiel in drei Darstellungen, das nicht Teil der Erfindung ist;
• Fig. 18 ein Ausführungsbeispiel der Erfindung mit einem geschlitzten Glockentellergewinde in zwei Darstellungen; und
• Fig. 19 eine nicht beanspruchte Ausführungsform mit einem Sondergewinde in zwei Darstellungen.

Show it

• Fig. 1 the fastening device of a bell cup according to an embodiment which is not part of the invention.
• Fig. 2 an embodiment which is not part of the invention, with a union nut for locking the bell cup;
• Fig. 3A a further embodiment with a union nut, which is not part of the invention;
• Fig. 3B a cut through Fig. 3A along the plane 3B-3B;
• Fig. 4 another embodiment with a union nut, which is not part of the invention;
• Fig. 5A an embodiment with a double thread, which is not part of the invention;
• Fig. 5B a modification of the embodiment according to Fig. 5A ;
• Fig. 6 another embodiment with a double thread, which is not part of the invention;
• Fig. 7A an embodiment with the bell cup in the hollow shaft arresting spring molding ring;
• Fig. 7B a cut through Fig. 7A along the plane 7B-7B;
• Fig. 8 an embodiment of the invention with an O-ring, which is not part of the invention;
• Fig. 9 another embodiment with an O-ring, which is not part of the invention;
• Fig. 10 an embodiment of the invention with a snap ring, which is not part of the invention;
• Fig. 11 a further embodiment with a snap ring, which is not part of the invention;
• Fig. 12 an unclaimed embodiment with a bayonet in three representations;
• Fig. 13 an unclaimed embodiment with a bayonet lock and an additional lock construction in four representations;
• Fig. 14 an unclaimed embodiment with a bayonet closure in two representations;
• Fig. 15 a modification of the embodiment according to Fig. 14 with a lock construction in three representations;
• Fig. 16 an unclaimed embodiment with an axially acting safety catch in three representations;
• Fig. 17 another, characterized by a retaining ring embodiment in three representations, which is not part of the invention;
• Fig. 18 an embodiment of the invention with a slotted bell cup thread in two representations; and
• Fig. 19 an unclaimed embodiment with a special thread in two representations.

At the in Fig. 1 illustrated arrangement of the bell cup 1 is fixed in the example of an air turbine driven hollow shaft 2 of a high-rotation atomizer. The shaft 2 has for this purpose an internal thread 3, in which the bell cup 1 is screwed to the external thread 4 of its cylindrical hub part 5. For centering of the bell cup 1 is a conical, extending to the front end of the bell cup adjacent to the thread widening portion 6 of the bell cup to a corresponding conical inner surface 7 at the open end of the hollow shaft 2. The bell cup 1 can be easily unscrewed for replacement or maintenance purposes, for example manually and lockable shaft without tools from the shaft and just as easily screwed into it. The arrangement shown is essentially rotationally symmetrical. It corresponds, so far described, conventional rotary atomizing eg according to EP 0 715 869 B1 and therefore needs no further explanation.

The bell cup 1 integrally formed part of the hub part 5 could conventionally rest directly on the inner wall of the hollow shaft 2, but sits in the in Fig. 1 illustrated embodiment between the integrally formed part and the hollow shaft, a centering ring 5 'of the illustrated, tapered at one end and cylindrical end at the threaded end, on the conical inner surface of the conical part of the hub part 5 abuts, while its conical outer surface rests against the conical inner surface of the hollow shaft 2 , and may be screwed onto the molded part of the hub part 5 or fastened in other ways, for example. Instead, the centering ring 5 'can also be fixed in the end of the hollow shaft 2 and consequently the bell cup can be unscrewed from the centering ring 5' remaining in the shaft.

According to the non-claimed embodiment described here, the arrangement shown differs from known constructions but mainly by a shrink connection between the bell cup 1 and the hollow shaft 2. In the idle and in the operating state of the arrangement shown, eg at room temperature, is over the entire area or at least at individual points of the cylindrical portion in which or on which the hub portion 5 and the centering ring 5 'rests against the inner wall of the hollow shaft 2, the inner diameter of the hollow shaft (which can change, for example, by the cone shape along the axial direction) so smaller dimensioned as the outer diameter of the hub part 5 and 5 'to the respective mounted with the bell cup along the axial direction corresponding points that these parts are inextricably linked together in the mounted state. With the appropriate accuracy of fit this usually suffices for a diameter difference in the 1/100 mm range. This fastening device can now be achieved by heating and the resulting radial expansion of the existing in a known manner of metal hollow shaft 2, so that the bell cup 1 can be easily unscrewed from the heated hollow shaft. Similarly, the hollow shaft is heated when the bell cup is to be screwed into its open end. The heating can be achieved in a simple manner, for example by placing an electrically powered pliers on the element to be heated. A suitable possibility for this is an inductive forceps.

Fig. 1 only serves to explain the embodiment considered here when applied to a known connection arrangement. Since it may be difficult and / or inappropriate in practice in practice atomizers to heat the drive shaft should preferably not be used in a hollow shaft in the considered embodiment, the hub portion of the bell cup, but with its hub part as an outer part, the circumference of the drive shaft. By placing the above-mentioned induction pliers, the hub part of the existing example of titanium material bell plate can be easily taken and radially expanded by the heating and the bell cup then placed on the drive shaft or just as easy to dismantle, resulting in no significant heating of the typical steel drive shaft is possible. Also deviating from the in Fig. 1 illustrated embodiment, the bell cup is preferably not bolted to the drive shaft in this embodiment further. For a safe and reliable shrink connection, the adjacent cylindrical surfaces may rather be smooth, so that the bell cup much faster and easier than before assembled and disassembled can be. However, if it is required to increase the security, other, faster detachable and mountable form-locking structures are conceivable instead of the screw. In principle, the shrink connection is suitable for arbitrarily assembled connecting parts of the bell cup and the drive shaft.

At the in Fig. 2 The arrangement shown is similar to Fig. 1 the hub portion 25 of the bell cup 21 with the interposition of a centering ring 25 'used to form a centering cone in the conical end of the hollow shaft 22. The hub part 25 and the centering ring 25 'are connected by at least two evenly spaced around the axis of rotation radial screws 27 whose head is slidable in a radial slot 23 in the inner wall of the hollow shaft 22, so that the radial screws 27 a relative rotation between the Bell plate 21 and the hollow shaft 22 prevent. To lock the bell cup 21 is a union nut 20 which is screwed onto an external thread of the hollow shaft 22 and with the at one end radially inwardly projecting edge 20 'axially on a radially outwardly projecting edge 28 of the bell cup or in the illustrated example of the centering ring 25 abuts. By tightening the union nut 20, it presses the centering cone of the bell cup 21 against the conical inner surface 26 of the hollow shaft 22. At its opposite end, the union nut 20 with mounted bell plate against a stop edge 29 of the hollow shaft 22 abut. To release the attachment, the union nut 20 must be unscrewed from the hollow shaft 22, after which the bell cup 21 can be pulled out of the hollow shaft. An automatic release of the attachment by acting on the bell cup braking or acceleration forces, however, is practically impossible.

The fuse with a union nut 20 can be realized without the radial screws 27. For example, the hub portion 25 or centering ring 25 'could be similar to FIG Fig. 1 screwed into an internal thread of the hollow shaft and unscrewed after removing the nut, it is useful if the threads of the nut and the hollow shaft opposite direction (right or left) have.

Fig. 3A shows a modification of the embodiment according to Fig. 2 with a cap nut 30, which is not screwed onto the hollow shaft 32, but on an external thread 34 of the centering ring 35 '(or the hub portion 25 or other part of the bell cup 31, if no separate centering ring is provided).

Another feature is that axial movement of the cap nut 30 relative to the hollow shaft 32 is prevented by one or more equally spaced angularly spaced locking members, in the illustrated example by the locking screws 33 tangential in a plane perpendicularly intersecting the axis of rotation common plane are screwed into the union nut 30 and engage in an annular recess 39 in the outer periphery of the hollow shaft 32. An expedient shape and arrangement of the locking screws 33 are the sectional view of Fig. 3B refer to. The radial screws 37 correspond to the screws 27 in FIG Fig. 2 ,

Also at the in Fig. 4 illustrated embodiment, a union nut 40 is provided for locking the bell plate 41. It is screwed at its one end to the hollow shaft 42 and engages at its other end with a radially inwardly projecting edge 40 'via an intermediate element on the bell plate 41 at. The intermediate member consists in the illustrated embodiment of a hollow shaft 42 at the end of molded elastic clip assembly whose end portion 48 mounted with bell plate in the manner of a clipper from the edge 40 'of the nut axially in the direction of the hollow shaft 42 against a stop surface 49 on the circumference of Hub portion 45 of the bell plate 41 is pressed. As a result, when tightening the nut 40, for example by a fork wrench similar to the embodiments according to Fig. 2 and Fig. 3 the conical portion 46 of the bell cup is pressed against the conical inner surface 47 of the hollow shaft 42. After loosening this screw the bell cup can be easily pulled out of the hollow shaft, wherein the radially compliant end portions 48 of the staple assembly are pushed by the surface 49 of the bell cup radially outward. The clamp assembly with the radially thickened end portions 48 as shown can be formed by a relatively thin annular shoulder of the hollow shaft 42 in the adjacent land area or by individual axially projecting clamp tongues. The clip assembly may be formed instead of the hollow shaft itself also attached to the hollow shaft separate component.

According to another embodiment (not shown), an example with Fig. 1 matching, so screwed in a known manner screwed into a hollow shaft bell cup with an additional union nut. The cap nut can simply be screwed onto an external thread on the end of the hollow shaft, which is axially slotted for this purpose, so that it clamps the slotted end to the hub part of the bell cup. The slotted shaft end could also be clamped by a union nut or a threadless union or sliding sleeve be screwed or pushed against a stop on the bell cup.

In another (also not shown) embodiment of the bell cup can be fixed in or on the drive shaft by, for example, spherical elements sitting in recesses or an annular groove on the outside of the inner member (bell cup hub or shaft) and in operation with a rotating bell cup by the centrifugal force are pressed outwards into a position in which they prevent relative axial movements of the two elements in corresponding recesses of the outer element. This connection can be secured with a screwed-on union nut or a retaining sleeve holding by spring force. The deferred cap sleeve can also be fixed by a snap-in by rotating and releasable bayonet lock.

At the in Fig. 5A illustrated embodiment is similar to in Fig. 1 the hub part 55 of the bell cup 51 with the external thread 54 of the screwed centering ring 55 'screwed into a first internal thread 53 of the hollow shaft 52 approximately the same length. The hollow shaft 52 has here but at an axial distance from the thread 53 in the direction opposite to the bell cup axial direction a second internal thread 53 ', which can be shorter than the first thread 53 and has a smaller diameter as shown. Between the two threads 53 and 53 'is in the inner wall of the hollow shaft 52, an axially relatively short annular recess 57, whose radial diameter is slightly larger than that of the external thread 54, while on the side facing away from the bell cup of the second thread 53' along the cylindrical inner wall of the shaft another annular or annular space-like recess 58 extends whose axial length is slightly greater than the length of the threads 53 and 54th

The mounting position of the bell cup is illustratively defined as in the other embodiments by conditioning the Zentrierkegels the bell cup on the conical inner wall of the hollow shaft. In this Monagestellung the centering ring 55 'of the bell cup 51 extends in the direction away from the bell cup with its cylindrical end portion 59 so far into the hollow shaft 52 in that it extends to the axial end of the second recess 58. In the vicinity of this axial end of the end portion 59 has as shown a second, axially relatively short external thread 54 ', the diameter and shape of the similarly short internal thread 53' of the hollow shaft 52 fit. The outer diameter of the thread 54 'is approximately equal to the diameter of the cylindrical recess 58 with a small clearance, so that the thread 54' when screwing in and unscrewing the bell cup can be easily moved in the groove. When mounted bell cup, the axial distance between the threads 53 'and 54' is slightly larger than the axial length of the threads 53 and 54. Preferably, the threads 53 ', 54' are opposite to the threads 53, 54 directed, so left-hand thread, if the Threads 53, 54 are right-hand threads. In addition to increased security against automatic loosening of the bell cup, this also has the advantage that the threads are less likely to pinch ("eat").

To remove the bell cup 51 is first completely unscrewed from the first internal thread 53 of the hollow shaft 52, wherein its second external thread 54 'in the groove 58 is pushed close to the second internal thread 53'. Then it is for removal from the hollow shaft with its second external thread 54 'in the opposite direction of screwing also unscrewed from the second internal thread 53. Installation is in the reverse order.

Thus, even when in operation, the bell cup 51 unintentionally automatically unscrews from the condentional thread 53, 54, the risk of skidding by immediate abutment of the second external thread 54 'on the second internal thread 53' reliably prevented. Even with a possible modification with the same thread direction of the two thread assemblies, this risk would be significantly reduced. Furthermore, by the described guidance of the thread 54 'in the cylindrical groove 58, which allows a virtually backlash-free radial support of the hub portion of the bell cup in the hollow shaft even during and after unscrewing from the first thread 53, 54, the risk of damage to the components the bell cup in the hollow shaft due to unbalance movements in the radial direction reliably avoided. For this purpose, the distance between the threads 53 'and 54' are dimensioned with mounted bell cup so that when loosening the bell cup whose thread 54 has just released from the thread 53, only the small minimum distance between the threads 53rd 'and 54' remains, which is necessary for the trouble screwing the thread 54 'in the thread 53' when removing the bell cup and during its assembly. Another advantage is that the two screwing can be done by hand and possibly with a simple tool.

In Fig. 5B a particularly preferred embodiment is shown, which in essential features with Fig. 5A in particular with respect to the two axially spaced internal threads 53B and 53B 'of the hollow shaft 52B and the associated, likewise axially separate external threads 54B and 54B' of a hub portion 55B of the bell cup, which correspond to the threads 53 and 53 'or 54 and 54', so that no further explanation of these threads and their functions is required. The threads 53B 'and 54B', which are designed for example as left-hand threads, also have a somewhat smaller diameter (eg M16) than the threads 53B and 54B (for example M18) designed as a right-hand thread in this example.

The hub part 55B in this embodiment is a one-piece annular body of the illustrated shape, which may be made of the same or a similar metal as the hollow shaft 52B, eg made of steel, and bolted to the hollow shaft similar to the centering ring 55 'in FIG Fig. 5A in contrast to the hub part 55 but is a separately manufactured from the outer part 51 B of the bell cup component. The outer part 51B of the bell cup may suitably be made of titanium material and be fitted on the inner circumference of its cylindrical inner ring part 56B, for example under right-hand screw connection at 57B, to an outer ring part 55B 'of the hub part 55B. Preferably, the connection of the housing or outer part 51 B of the illustrated bell plate with the receiving or hub portion 55 B is permanently fixed, for example by laser welding at the Verschraubungsstelle 57 B, wherein the weld at the end face of the bell cup is then od by over-turning. Like. Smoothed. The end face of the hub part 55B forming the inner part of the end face of the bell cup can be hardened to reduce wear, for example by laser hardening. In the hub part 55 B, the usual deflecting the bell cup is used, as indicated by the arrow U.

A particularly advantageous feature of the embodiment according to Fig. 5B is the conical positive connection of the Bell plate or here its hub part 55B with the hollow shaft 52B. This connection at 58B is preferably implemented as an HSK system according to the standard ISO 12164-1 (the abbreviation HSK for "hollow taper shank" is known as a designation for tool holders with a taper ratio of 1:10). The at this support point 58B conically widening in the direction of the end face of the bell cup inner surface of the hollow shaft 52B lies flat against the corresponding conical outer periphery of the hub portion 55B and terminates at the radially extending flat end face 59B of the hollow shaft, which is shown as a stop of the HSK system against a corresponding radially inner surface of the hub part abuts, wherein the hollow shaft and hub part are aligned with each other at its outer periphery.

This HSK system has many important advantages in attaching the bell cup of a high-speed rotary atomizer:
It results in high rigidity against lateral forces, with a significant reduction of the plan impact (side impact or wobble), ie high axial runout and high balancing quality can be achieved. It results in high radial and axial accuracy, with grinding is possible because no interference contours are present. Also important is very good reproducibility when replacing the bell cup. Further advantages are high torsional strength and bending load capacity of the construction. By the so-called edge layer technology for hardening the end face of the hub part 55B, the wear of the bell cup can be reduced. Important is the achievable high concentricity accuracy of the bell cup, which allows high speeds and at the same time bell plates with large outside diameters.

This in Fig. 5A and 5B illustrated embodiment can be modified such that the short second threads 53 ', 54' are replaced by a different type of stop construction with a similar mode of action. For example, may be provided instead of the thread 53 'individual radially inwardly projecting pins of the hollow shaft, which can be pushed at the mounting of the bell cup by corresponding slots of a instead of the thread 54' provided stop ring on the bellcrank hub.

There is also the possibility of providing an additional securing element, e.g. to install a spring washer.

The embodiment according to Fig. 5A and 5B can also be found in the Fig. 6 modify it. Here, the hollow shaft 62 has two through the annular groove-like recess 67 axially spaced apart internal thread 63 and 63 'the same direction (eg right) with the same outer diameter. When the bell cup 61 is mounted, the internal thread 63 'facing away from the bell cup is engaged with an external thread 64 of the bell cup or its centering ring 66. The thread 63' facing away from the bell cup can be longer than the thread 63 in this embodiment. The length of the recess 67 and thus the thread pitch are similar here as in Fig. 5 only just sized so large that when unscrewing the bell cup from the one internal thread 63 'only the minimum distance between the external thread 64 and the internal thread 63 remains, which is necessary so that subsequently the threads 64 and 63 can be brought without difficulty into engagement. This embodiment has similar advantages as the embodiment of Fig. 5 , Another embodiment with a stopper construction and similar advantages as according to Fig. 5 and Fig. 6 is in Fig. 7A shown. Again, this is similar to in Fig. 1 the bell cup 71 with the external thread 74 of the centering ring 75 screwed into the internal thread 73 of the hollow shaft 72. Similar to in Fig. 5 the centering ring 75 has a cylindrical end portion 79 which extends into the hollow shaft 72 inside. The end part has shown in its peripheral surface an annular recess or a cylindrical annular groove 77 which is bounded on the bell cup 71 side facing away from an end ring 79 ', which has the illustrated, conical in cross-section shape with radially outwardly to the ring center inclined end surfaces , The outer diameter of the end ring 79 'is slightly smaller than that of the external thread 74, so that it can be pushed through the internal thread 73 of the hollow shaft. On the opposite side, however, the annular groove 77 is delimited by a shoulder 75 'adjoining the thread 74 on the circumference of the centering ring 75. In the region of the annular groove 77, the inner diameter of the hollow shaft 72 is approximately equal to the outer diameter of the end ring 79 ', so that it can be moved with at most slight radial play in this area axially under the leadership of the hollow shaft.

When mounted bell plate is aligned with the shoulder 75 'provided in the inner wall of the hollow shaft 72 annular groove 76 in the captive a spring molding ring 70 is seated. The molding ring 70 may, for example, the in Fig. 7B have shown shape with the radially inwardly to the cylindrical circumference of the annular groove 77 of the end portion 79 of the bell plate protruding bulges or shaft portions 70 '. So that the mold ring 70 can be easily inserted into the annular groove 76 and allows radial movements of its shaft sections, it does not form a closed ring, but has the visible at 78 gap. The shape and arrangement of the shaft portions 70 'may be such that the molding ring 70 is balanced and does not create imbalance forces.

When the bell cup 71 is unscrewed for removal from the hollow shaft 72 or unintentionally unscrews itself, (similar in principle to the exemplary embodiments after Fig. 5 and 6 ) First, the end ring 79 'of the bell cup or its centering ring 75 against the radial projections, ie shaft portions 70' of the mold ring 70, once the threads 73 and 74 have been disengaged. The length of the annular groove 77 can be dimensioned so that after loosening the screw no significant distance between the end ring 79 'and the radial plane of the mold ring 70 remains on its side facing away from the bell cup. As a result of the construction described, the bell cup 70 can not be unintentionally ejected from the hollow shaft with appropriate dimensioning of the spring ring, and the guide of the end ring 79 'on the inner wall of the hollow shaft 72 also prevents unbalanced forces generating radial movements of the bell cup. Wanted, for example, by hand, the bell cup, however, can be easily removed after loosening the screw from the hollow shaft and just as easy to use because with a corresponding axial force the oblique edges of the end ring 79 'can push away the projections or shaft portions 70' outwardly into the annular groove 77 , In case of accidental unscrewing the bell cup, however, such axial forces can not occur.

The embodiment according to Fig. 7 can be modified so that instead of the spring-shaped ring 70 and the end ring 79 'other stop structures are provided, for example, with radially inwardly or outwardly projecting noses and pins.

Furthermore, embodiments (not shown) are conceivable in which the bell cup with its hub part on or in the drive shaft slidably guided, that is not screwed on and to its fixation only one inserted between the bell cup and the shaft in a respective annular groove spring ring is provided, for example, according to the mold ring 70 in Fig. 7 ,

In the embodiments in which a circlip is used, this can be useful also formed sawtooth.

In Fig. 8 an embodiment is shown with a bell cup 81 which rests for centering with the conical portion 86 of its hub portion 85 on the corresponding conical inner surface 87 of a hollow shaft 82, at the end thereof similar to the embodiment according to Fig. 4 an elastic clip assembly with nose-like radially inwardly projecting end portions 88 integrally formed (or as a separate component attached) is. The nose-like end portions 88 of the shaft 82 are of the radially inwardly projecting end edge 80 'one with the nut in Fig. 4 comparable cap sleeve 80 pressed against the stop surface 89 on the circumference of the hub portion 85. The cap sleeve is seated as shown with its end edge 80 'axially opposite smooth cylindrical inner surface 80''on the circumference of the hollow shaft 82, for example axially in the region or in the vicinity of the conical surface 87. In contrast to Fig. 4 the cap sleeve 80 is not screwed onto the hollow shaft 82, but fixed on it only by an O-ring 83, which may consist of a suitable rubber-elastic plastic. As shown, the O-ring 83 can be inserted into an annular groove in the outer circumference of the hollow shaft 82 in such a way that it presses against a radial or oblique stop surface 84 facing it on the inside of the cap sleeve 80. To release the connection between the bell cup 81 and the hollow shaft 82, the cap sleeve 80, overcoming the frictional force of the O-ring 83, if necessary, using a release tool inserted into the groove 80 "'on the outside of the sleeve 80 so far on the shaft 82nd that their end edge 80 'will disengage the shaft end portions 88. The bell cup may then radially push the end portions 88 away and be easily removed from the shaft, as well as being simply reversed.

Another embodiment with a serving for fixing the bell cup 91 on the shaft 92 elastic O-ring 93 is in Fig. 9 shown. The O-ring can be like at Fig. 8 sit in an annular groove in the outside of the shaft 92 and press against the radial or oblique stop surface 94 of an annular groove 90 'in the seated on the shaft circumference smooth cylindrical inner surface 90 "a cap sleeve 90th Fig. 8 This embodiment differs mainly in that the clip assembly is missing at the shaft end and the cap sleeve 90 is secured by a not self-releasable screw or other connection to the hub portion 95 of the bell cup. For centering of the bell cup 91 is located with the conical portion 96 of its hub portion 95 on the corresponding conical inner surface 97 at the end of the cap sleeve 90 at. Since in this embodiment, the bell cup 91 is held only by the bias and friction of the O-ring 93 on the shaft 92, it can be removed even faster and easier from the shaft and mounted just as quickly and easily. A particular advantage of the separate cap sleeve is also in that the bell cup itself can be made simpler and easier to produce.

Another possibility, not shown, consists in a clamp arrangement in which a clip-shaped part is attached to the bell-shaped plate, which is preferably provided with the usual centering cone, by screwing, e.g. can be made of plastic. This Klipsformteil can then be clipped to attach the bell cup in a correspondingly shaped receiving element of the hollow shaft.

Fig. 10 shows a modification of the embodiment according to Fig. 9 , in which the bell cup 101 with its hub part 105 or whose centering ring 105 'is also simply hineinschiebbar in the hollow shaft 102 and pulled out of it. The centering ring 105 'lies with its smooth peripheral surface as shown in the conical inner surface 107 and the subsequent cylindrical inner surface 108 of the hollow shaft and serves similar purposes as the centering rings of the embodiments already described, thus simplifying the bell cup itself, at the hub portion 105 he solvable, but not detachably attached by itself. To fix the bell cup on the shaft is used in this embodiment instead of the rubber elastic O-ring after Fig. 9 The snap ring 103 can be used as shown in an annular groove 109 in the outer side of the centering ring 105 'and radially projecting on its bellcrank facing side against a bell plate facing away from radial or inclined stop surface 104 in the inner surface 108 of the hollow shaft 102nd so that it prevents the bell cup from unintentionally moving out of the hollow shaft. To release the connection of the snap ring 103 with a tool or with a corresponding axial force by the for this purpose oblique stop surface 104 are compressed and thereby pressed into the annular groove 109, while it is compressed during assembly, so when inserted into the hollow shaft of the inner surface 108 before it snaps behind the stop surface 104. The bell cup is thus held only by the snap ring in the hollow shaft. The snap ring should be balanced regardless of its ring gap to avoid imbalance forces.

Fig. 11 shows a further embodiment with a sole locking element forming snap ring 113 which does not attack here on the inside of the hollow shaft 112, but is disposed in an annular groove 119 in the outer surface of the hollow shaft 112. With its radially protruding from the annular groove 119 part of the snap ring 113 abuts a bell plate 111 facing radial or inclined stop surface 114 in the inside of a centering ring 115, which in principle the centering ring 105 'in Fig. 10 corresponds, but as shown encloses the outside of the hollow shaft 112. The assembly and disassembly of the bell plate carried out similar to the embodiment according to Fig. 10 ,

At the in Fig. 12A illustrated embodiment, the cylindrical hub portion 125 of the bell cup 121 with its smooth peripheral surface on the smooth cylindrical inner surface 127 of the hollow shaft 122 at. At its shaft-side radially extending end face 125 'abuts the hub portion 125 of the bell cup against the axial edge of an axially displaceable on the inner surface 127 of the hollow shaft adjacent cylindrical ring body 123 which abuts on its axially opposite side against a likewise coaxially arranged in the hollow shaft 122 coil spring 124 , The coil spring 124 is in turn based on its the bell cup opposite end of a fixed in the hollow shaft (or formed by the hollow shaft) ring member 122 'from.

For fixing the bell cup 121 in the hollow shaft 122, a bayonet lock is provided in this embodiment. It is formed by a fixed in the wall of the hollow shaft bolt or other pin 120 which engages radially projecting from the surface 127 inwardly into a machined into the outside of the hub portion 125 of the bell cup form slot 128. The shape of the slot 128 is the otherwise schematic representation of the hub portion 125 and the ring body 123 in Fig. 12B refer to. The slot 128 thus extends axially inwardly from its axially outwardly open end in the end surface 125 'of the hub portion 125 to the U-shaped portion and terminates at the axially closed end 128' of the second U-leg. At the in Fig. 12A shown working position of the bell cup 121 is pressed by the clamping force of the compression spring 124 via the annular body 123 against the voltage applied to the slot end 128 'of the bell cup pin 120 and thus fixed axially in the shaft. To release this attachment of the bell plate 121 is pushed against the force of the spring 124 in the hollow shaft 122 until the bell cup, the in Fig. 12C achieved dismantling position, wherein the pin 120 abuts against the axially inner end of the mold slot 128. After the bell cup has been rotated so that the pin 120 is in the axially open U-leg of the mold slot 128, the bell cup can be easily pulled out of the hollow shaft. Installation is just as easy in reverse order. To hold the hollow shaft 122 during assembly and disassembly of the bell cup, a tool can be attached to the recesses 129 of the shaft.

Although only one pin 120 is shown, it is convenient that at least two or more pins 120 and slots 128 are distributed at equal angular intervals about the axis of rotation so that no imbalance forces occur.

Instead of in the shaft, the bayonet locking pins could also be mounted in the hub portion of the bell cup and introduced into the form of slots of the shaft in a modification of this embodiment.

Also at the in Fig. 13A illustrated embodiment, the bell cup 131 is similar to in Fig. 12 mounted with its hub portion 135 without screwing on the smooth inner surface 137 of the hollow shaft 132 adjacent axially displaceable in the hollow shaft and attached to it by a bayonet lock, which is provided in this example with an additional lock. The bayonet catch construction includes one, two, or more pins 130 distributed about the axis of rotation to prevent imbalance forces, which are shown mounted in the hub portion 135 of the bell cup and radially outwardly projecting into two radially adjacent die slots 136 and 138, respectively. The radially outer mold slot 138 is located in the cylindrical wall of the hollow shaft 132 and extends from the glockentellerseitigem end axially inward, then according to Fig. 13B in the circumferential direction and finally axially back to a stop surface on the in Fig. 13B the pin 130 is applied. The radially inner mold slot 136, however, is located in a cylindrical ring body 133, which is similar to Fig. 12 axially displaceable in the hollow shaft against the force of a compression coil spring 134 which is supported at its opposite end to a shoulder or ring element of the hollow shaft. The slot 136 extends from the glockentellerseitigen end of the annular body 133 axially inwardly. The ring body 133 is relative to the bell cup slidably inserted into an annular recess on the circumference of the hub portion 135, wherein the inner diameter of the hollow shaft 132 corresponding cylindrical outer surfaces of the annular body 133 and the hub portion 135 are aligned. In the ring body 133, one or preferably a plurality of further pins 133 'distributed around the axis of rotation are fastened, which are displaceable radially outward in axial slots 138' of the hollow shaft 132 and realize the additional lock function. The slots 136, 138 and 138 'may be closed radially outward by a cover ring 139 secured to the hollow shaft.

The shape of the slots 136 and 138 is shown in the schematic diagrams of FIGS Figs. 13B and 13D recognizable. At the in FIGS. 13A and 13B shown working position of the bell cup 131 pushes the coil spring 134 via the annular body 133 whose pin 133 'against the radially extending stop surface of the hollow shaft 132 at the glockentellerseitigen end of its slot 138' and the pin 130 of the bell cup against the radially extending stop surface on the glockentellerseitigen end of the slot 138 (cf. Fig. 13B ), whereby the bell plate connected to the ring body 133 is fixed in the shaft.

To release its attachment, the bell cup is pushed against the force of the spring 134 in the hollow shaft 132, so that he in FIGS. 13C and 13D achieved dismantling position, wherein the pin 133 'of the annular body 133 now abuts against the radially extending abutment surface at the end remote from the bell cup end of the slot 138' and the pin 130 against the corresponding axial end of the mold slot 138 and the bell plate facing away from end portions of the molding slots 136 and 138 are aligned. This disassembly position can be fixed by means of a tool W, which is through the recognizable at W1 and W2, in this position aligned openings in the hollow shaft and its cover 139 and in the hub portion 135 is inserted, and at the representation of the bell plate facing edge of the annular body 133 abuts. By turning the bell cup, the pin 130 passes into the outgoing from the hollow shaft portion of the mold slot 138, wherein it is also in the leading out of the ring body 133 part of the slot 136, so that the bell cup of the ring body 133 off and out of the hollow shaft can be pulled out, wherein the retained by the tool W in the hollow shaft W annular body 133 remains in the hollow shaft 132. The mounting of the bell plate takes place in reverse directions.

An embodiment with a bayonet lock without separate counterpressure spring in the interior of the hollow shaft is in Fig. 14A shown. The bell cup 141 is here also without screwing, but with the formation of the illustrated cone with its hub portion 145 on the smooth inner surface of the hollow shaft 142 at. As shown, the wall of the hollow shaft 142 at its glockentellerseitigem end 142 'adjacent to the cone thinner than the main part of the shaft on the opposite side. The bayonet catch construction includes one, two or more pins 140 distributed around the axis of rotation to prevent imbalance forces, which are secured in the hub portion 145 and engage radially outwardly therewith into each milled slot 146 of the quill 142, for example. As in Fig. 14B can be seen, the slot 146 extends axially from the end of the hollow shaft into this and then goes into a transversely angled inner part 146 ', at the end of the pin 140 rests in the operating position. In this position, the one or more pins 140 are held by a respective spring element 143 of the hollow shaft. In the example shown, the spring element 143 formed by a tongue-like edge portion on the bell-plate-side end of the shaft itself, by the in Fig. 14B recognizable, for example, in extension of the inner part 146 'milled slot 144 is separated from the axially inner part of the shaft and presses resiliently against the pin 140. To protect the pin, slot and spring construction, for example, from contamination is used at the end of the hollow shaft 142 on the periphery patch cover 147th

To mount the bell cup 141, its pin 140 is pushed axially into the slot 146 and then locked by turning the bell cup in the inner part 146 'of the slot. The disassembly takes place against the force of the spring element 143 in the reverse order. The hollow shaft can hereby (as in Fig. 12 ) are held by a 149 attachable tool.

Also in Fig. 15A an embodiment is shown with bayonet without counter-pressure spring in the interior of the hollow shaft, the representation largely according to the embodiment Fig. 14 corresponds, but is additionally provided with a lock to secure the operating position. Further, here the bell plate facing relatively thin end portion 152 'of the hollow shaft 152 is not integrally formed, but used as a separate axial extension in the inner wall of the hollow shaft. On the other hand, as in the case of Fig. 14 one, two or more in the hub portion 155 of the bell cup 151 attached pins 150 in each one of the edge of the end portion 152 'from first axial and then into a transversely angled inner part 156' passing slot 156 in which the pin 150 through an example by Milling the shaft end portion 152 'formed spring element 153 is clamped. As lock elements serve additional pins 158 ( Fig. 15A ) and 258 ( Fig. 15B ), which in a rotatable on the circumference of the Shaft end portion 152 'seated ring member 157 are fixed and protrude from this radially inwardly. The one pin 158 engages the glockentellerseitigen end edge of the spring element 153 and presses an axially inwardly projecting latching lug 153 'of the spring element 153 against the pin 150, that this is not by turning the bell cup relative to the hollow shaft of the in Fig. 15B shown operating position can be pushed out. The other lock pin 258 presses against another at a different, for example in the circumferential direction of the shaft end portion 152 'provided further spring element 253, which is similar to the spring element 153 formed, but two spaced apart in the direction of rotation axial indentations, in which the lock pin 258 depending on Rotary position of the ring member 157 can engage relative to the hollow shaft 152 to prevent automatic rotation of the ring member 157 and thus releasing the lock fuse. For example, by a stop construction between the ring member 157 and the end portion 152 ', as seen at 159, an axial displacement of the ring member 157 is prevented relative to the shaft.

To release the bell cup 151 from its in Figs. 15A and 15B shown operating position, the ring member 157 is rotated against the force of the spring element 253 so that the in Fig. 15C shown disassembly position of the pins 158 and 258 results, in which the pin 158 releases the voltage applied to the pin 150 of the bell cup spring element 153. As a result, now the bell cup 151 can be rotated relative to the hollow shaft 152 and its end portion 152 'until the pin 150 is in the axial portion of the slot 156 and the bell cup can thus be pulled out axially. The mounting of the bell plate takes place in the reverse order.

In all embodiments with a bayonet lock, the slots described can either in the hollow shaft itself or in an attached to the hollow shaft end portion (as in Fig. 15A ) or instead in the bell cup or in a part attached to the bell cup. Accordingly, the pins described may be mounted in the bell cup or in the shaft or in a part attached to the bell cup or shaft, depending on the location of the slots.

In Fig. 16A are simplified only part of the open end of the hollow shaft 162 and the corresponding part of the screwed into the hollow shaft hub portion 165 shown. In this further embodiment, the bell cup 161 may be conventional in itself to form a centering cone partially conical hub portion 165 and its axially adjoining the centering taper thread 163. For example, the construction could so far with Fig. 1 to match. Of known constructions, however, the partially schematically illustrated embodiment differs in that on one transverse to the axis of rotation, facing away from the bell cup direction end face 165 'of the hub portion 165 locking means are arranged such as a coaxially extending around the axis of rotation ring from axially from the end face 165 'protruding front teeth 166, which are in engagement with an axially opposite ring of locking teeth 167 of the hollow shaft 162 when the bell cup is screwed in its mounting position in the hollow shaft. The ratchet teeth 167 can axially, for example, of the

Glockenteller facing end face of a ring member 168 projecting, which prevented in the mounting position at a relative rotation, but axially displaceable in the hollow shaft 162nd can be used. The ring element 168 is pressed axially against the front teeth 166 of the bell cup by a spring device arranged on its rear side facing away from the bell cup. For example, this spring device can simply consist of an elastic O-ring 169 inserted into the hollow shaft. The relative rotation of the ring member 168 in the shaft can be prevented by the frictional force of the O-ring 169 or by a form-fitting guide.

In this embodiment, as a result of blocking the shaft or other sudden speed changes, torques occur which could cause the bell cup itself to unscrew from the shaft, it is prevented from doing so by engagement of the spur teeth 166 with the ratchet teeth 167. The unscrewing of the bell cup for disassembly, however, is readily possible because with a corresponding edge shape of the teeth 166 and / or 167 and correspondingly greater torque the ring member 168 of the teeth 166 axially against the spring force, for example, the O-ring 169 can be pushed back. It is also conceivable to press the ring element 168 back for this purpose with a tool. The mounting of the bell plate is just as easy in reverse order.

Possible embodiments of the frontal teeth of the bell cup and the spring-mounted shaft insert are in Figs. 16B and 16C shown. For example, accordingly, the number of ratchet teeth 167 of the ring member 168 may be greater than that of the locking teeth 166 of the bellcrank hub engageable with them according to the dashed arrow. The reverse arrangement is possible, as well as a larger or smaller number of teeth on the two sides of this locking arrangement. In any case, the teeth are to avoid imbalance forces distributed at equal mutual angular intervals around the axis of rotation.

In Figs. 17A and 17B is only schematically and greatly simplified an embodiment shown in which the bell cup 171 is prevented by a slotted locking ring 170 from automatically releasing from the hollow shaft 172, in which it is screwed in a conventional manner. The bell cup 171 shown outside the hollow shaft 172 has axially following the centering cone 176 the usual hub portion 175 with the external thread 174 corresponding to the conical inner surface 177 and the internal thread 174 'of the hollow shaft 172.

Between the cone 176 and the hub portion 175 of the bell cup 171, a cylindrical hub portion 173 is formed with respect to the external thread 174 reduced outer diameter by a radial recess. When the bell cup is screwed into the hollow shaft, this hub portion 173 is axially aligned with an annular groove 178 of at least approximately equal width formed by a recess in the inner wall of the hollow shaft 172 between its inner surface 177 and the inner thread 174 '.

In the formed between the cone 176 and the hub portion 175 of the bell cup piercing or annular gap 173 'is on the circumference of the hub portion 173 of in Fig. 17B illustrated, divided by a representation with respect to the radial direction obliquely completely through the annular body through slot 179 divided retaining ring 170 whose outer diameter may be slightly smaller than that of the external thread 174 or at least as the radially narrowest inner part of the shaft in front of the internal thread 174 ', so that he screwed in and wanted unscrewing the Bell plate in or out of the hollow shaft is not hindered. On rotation of the bell cup in operation, however, the locking ring 170 expands radially due to the centrifugal force and the oblique slot 179 to such a large outer diameter that it prevents an automatic unscrewing of the bell cup, for example, in blockage of the shaft because he against the annular gap 173 ' the bell cup and the groove 178 of the hollow shaft abuts paragraphs. For dynamic reasons, the locking ring 170 should preferably be as light as possible, for example made of plastic, and as the hub portion 173 and the groove 178 have the smallest possible diameter.

A (not shown) possible modification of the embodiment according to Figs. 17A and 17B consists in the annular gap 173 'and the groove 178 to use an elastic O-ring with a corresponding outer diameter, which allows the desired screwing and unscrewing of the bell cup, but by frictional forces prevents unwanted unscrewing.

Fig. 18A shows a bell cup 181, which similar to the embodiment according to Fig. 17A (and thus as in Fig. 1 ), for example adjacent to a centering cone has a hub portion 185 with an external thread 184, with which it is screwed into the (not shown) hollow shaft.

The screw connection is thereby secured in this embodiment against an automatic loosening, the thread 184 by a plurality of axially extending to the shaft-side end edge of the hollow cylindrical hub portion 185 and passing completely through the wall of the hub portion slots 182 'in correspondingly many elastic segments 182 in this embodiment is divided. The outer diameter of the thread 184 formed by the segments 182 is sized that it bears with a sufficient to secure the screw bias on the internal thread of the hollow shaft, which presses the segments when screwing against their spring force radially inward.

According to an additional feature of the invention which is essential for this embodiment, the cylindrical interior of the slotted hub part 185 has the in Fig. 18B shown annular body 180 is inserted, which abuts with its cylindrical outer surface closely to the cylindrical inner wall of the hub portion 185 and thus the slots 182 'seals to the inside. Preferably, the ring body 180 for this purpose made of rubber-elastic material, so that it does not hinder the required spring movements of the thread segments 182 when screwing and unscrewing the bell cup, but strengthens their spring force.

This sealing of the slots 182 'inwards is important, inter alia, in rotary atomizers, in which a liquid can be located in the interior of the hub part, as in the case of the example in US Pat EP 0 715 896 described rotary atomizer, in which a rinsing liquid is passed from the interior of the bell body to the outside of the bell.

According to Fig. 18B the ring body 180 on its outer side radially projecting flat webs 186 are formed, which can be sized and arranged so that they engage in the slots 182 'and at least completely fill their radially inner regions.

As a modification of the described embodiment is also conceivable to form the end portion of the hollow shaft through longitudinal slots as resilient thread segments. In this case the described preferably rubber-elastic annular body 180 could be inserted into the end portion of the hollow shaft. According to a in Fig. 19A illustrated further embodiment, the threads, with which a bell cup, for example, according Fig. 1 is bolted to the associated shaft, be arranged and designed so that in comparison with the usual thread ( Fig. 19B ) results in a higher holding force by increasing the unseating of the bell cup friction forces. At the in Fig. 19A This thread is achieved by the fact that the bisector W of the flank angle β of the thread against the perpendicular to the axis of rotation A radial plane E is inclined α by a certain angle, so that with the same outer diameter, the one flank surface F1 is greater than the other opposite her Flank surface F2. As shown, the direction of inclination corresponds to the pitch direction (right or left) of the thread, such that when the bell plate is screwed tight, the flanks with the larger area are pressed against one another. The increase in the edge pressure and thus the friction force follows from the greater length or area of the mutually depressed flanks of the same design threads of the bell cup and the hollow shaft. In the thread shown with a flank angle of 60 °, the angle of inclination α is about 20 °, but it may also be larger or smaller and, for example, be approximately between 5 ° and 25 °. Preferably closes at the in Fig. 19A shown external thread of the bell cup on the right in the drawing page of the thread of the usual centering cone of the bell cup.

Incidentally, apart from the angle of inclination α, the thread may correspond to any standard thread common to bell cups, as it compares in Fig. 19B is shown. Common are, for example, standardized fine threads M18x1 (nominal diameter 18 mm, thread pitch 1 mm).

This in Fig. 19A shown special thread can be made for example with a 60 ° turning tool, which is not made as usual perpendicular to the workpiece surface, but obliquely according to the angle α.

All described embodiments, in which the hub part of the bell cup is inserted into a hollow shaft, can be modified without changing the principle described in each case such that the hollow shaft form the inner part and the hub part of the bell cup the outer part of the compound.

The invention is defined by the claims. It should also be pointed out that any combinations of the various described embodiments are possible, the respective features of which may also be expedient in other exemplary embodiments.

Claims (9)

1. A spraying body (71) for a rotary atomiser for a coating machine, the spraying body being configured to be mounted on the drive shaft (102) of a drive motor and rotating during coating, and comprising a detachable fastening device (74) for coaxial connection of a cylindrical and/or conical connection member of the spraying body with the drive shaft, wherein the connection member (75) of the spraying body is configured to be placed in or on the drive shaft so that they form inner and outer elements, and wherein one or more radially movable locking elements (70) are arranged in the outer side of the inner element, the locking elements being pushed by the centrifugal force into radially adjacent recesses of the outer element when the spraying body is rotating, thereby preventing a relative axial movement of the inner and outer elements, and wherein the locking element or elements (70) prevent an automatic complete detachment of the fastening device (74) at deceleration or acceleration of the spraying body, whereas they are rendered ineffective at standstill of the spraying body in order to allow detachment of the fastening device (74).
2. The spraying body according to claim 1, wherein the fastening device is a screw fastening device.
3. The spraying body according to claim 1 or 2, wherein the locking element or elements prevent unintentional movements of the spraying body radially with respect to the rotation axis, whereas they are rendered ineffective at standstill of the spraying body in order to allow detachment of the fastening device.
4. The spraying body according to one of the preceding claims, wherein the spraying body (51) is configured to be fastened on the drive shaft (52) by a screw connection, wherein the drive shaft (52) or a member fixed thereon and/or the spraying body (51) or an annular member (55') fixed thereon comprise two threads (53, 53', 54) separated from one another, the threads preferably being separated from one another by an axial space (58).
5. The spraying body according to claim 4, wherein the thread (53, 54) facing the spraying body (51) has a larger diameter than the thread (53', 54') facing away from the spraying body.
6. The spraying body according to claim 4 or 5, wherein one of the preferably axially spaced threads is a right thread, and the other one is a left thread.
7. The spraying body according to one of the preceding claims, wherein the spraying body (161) is configured to be fixed on the drive shaft (162) by a screw mechanism (163), and the spraying body and the drive shaft are provided with axially engagable latching means (166, 167).
8. A rotary atomiser having a spraying body according to one of the preceding claims.
9. A drive shaft for a rotary atomiser with a spraying body according to one of the claims 1 to 7.

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