DE19719178C2 - Workpiece holder device for a blasting system for blasting workpieces with blasting material - Google Patents

Description

The invention relates to a workpiece holder device for a blasting system,

• - When working in a blasting cabinet with workpieces Blasting material to be irradiated using at least one Blasting material acceleration device into the blasting cabin is hurled
• - Wherein the workpiece holder a head lying in the blasting cabin Has axis of rotation and is rotatable about this.

Such workpiece holder devices are known and are preferred, for example, in so-called monorails blasting systems used in which, for example, the surface Chen from metal castings or workpieces from one whose material is processed with steel balls as blasting material the.

Such a monorail blasting system 2 , which is shown schematically in FIGS. 6 (side view) and 7 (top view), essentially consists of

• - A blasting cabin 4 with at least one attached blasting material acceleration device 5 , for. B. a slinging unit,
• a blasting material bunker 33 ,
• - A bucket elevator 32 , with which the blasting material already used in operation is transported back into the blasting material bunker 33 ,
• - A monorail 34 on which the workpiece holder 1 with the attached workpieces 3 to be machined is retracted into the blasting cabinet 4 and
• - A drive means 7 , by means of which the workpiece holder device 1 is rotated about its main axis of rotation 8 during operation.

The operation of such a system is as follows:

• a) The workpieces 3 to be machined are placed on the workpiece holding device 1 outside of the blasting cabin 4 ;
• b) Subsequently, this hanger from workpiece holder device 1 and workpieces 3 drive into the blasting cabin 4 ;
• c) The blasting process is started - for this purpose the blasting material acceleration device 5 in the form of a centrifugal unit, from the blasting material bunker 33 blasting material, for. B. steel balls, and the centrifugal unit 5 throws it at high speed into the cabin interior and consequently also on the currently located in the jet cone 37 of the centrifugal unit 5 surfaces of the workpiece holder 1 in the blast cabinet rotate the workpieces 3 (depending on the complexity and the desired surface quality of the workpieces, the blasting time is set beforehand);
• d) After the blasting process has ended, the hanger is moved out of the blasting cubicle 4 and the workpieces are removed from the workpiece holding device 1 ;
• e) The workpiece holder 1 is subsequently hung like the one with non-blasted workpieces 3 and the process begins again.

In conventional workpiece holder devices of the type initially mentioned for such blasting systems, the workpieces to be irradiated are arranged on workpiece holders 44 which, as shown schematically in FIG. 4, are firmly connected to a central suspension axis 36 lying on the main axis of rotation 8 and are consequently in operation turn around this.

This conventional embodiment of the workpiece holder device 1 has the following particular disadvantage: With the aim of achieving the best possible utilization of the cabin volume for cost and performance reasons and thus machining as many workpieces with a single beam pass, the workpiece holder device 1 becomes as tight as possible hung with workpieces 3 .

The shape and size of the hanger and the arrangement of which is arranged on the workpiece support device 1 works 3 is based on a compromise between performance and economy of a seites the blasting process and it-targeting surface finish of the workpieces 3 on the other.

This compromise takes, for example, the particular disadvantage that certain surfaces of the workpieces 3 when crossing the beam cone 37 are always taken only in a very specific blasting material incidence angle range and at a specific distance from the blasting material acceleration device 5 from the accelerated blasting material and that some surface areas of workpieces 3 are shaded by other workpieces 3 located on the hanger in such a way that they can only be hit by blasting material ricocheting off the surfaces of other workpieces 3 , that is to say by so-called ricochets.

The beam time to be set therefore depends on the point in time at which the most weakly irradiated surfaces of the workpieces 3 have an acceptable surface quality. In addition, when designing the sling, consideration must always be given to the disadvantageous factors described above. This is very disadvantageous from the point of view of the efficiency of the operation of the blasting system.

In some cases, therefore, sufficient surface qualities can be achieved on surfaces that are difficult to access for blasting material Costs of so-called radiation (= material washing out gen) on the other surfaces (especially on the the traversing of the jet cone to the centrifugal unit facing surfaces) or must be deficient  blasted surfaces are accepted for other purposes avoid radiation.

The situation described above is briefly explained below with reference to FIG. 5.

Each workpiece 3 located on the hanger is moved twice by the beam cone 37 when the hanger is rotated through 360 ° about the main axis of rotation 8 . The various side surfaces of each workpiece are irradiated to different extents, because on the one hand there are side surfaces that are always very close to the centrifugal unit when the blasting material angle of incidence is steep (see side surface 38 ), and on the other hand certain side surfaces only are facing the centrifugal unit at a great distance and are located in the jet cone (see side surface 39 ).

With a too dense arrangement of the workpieces 3 on the workpiece holder device 1 , as shown in FIG. 9 ge, there are too many shadows (dotted areas 35 ) of certain workpiece surfaces, which then only have transverse striking and therefore very slowed down blasting material can be hit.

Similar workpiece holding devices are from DE-PS 8 65 513 and US 4,519,171.

The present invention has for its object a Workpiece holder device to develop by at the same time the highest possible utilization of the blasting cabin vo lumens the most uniform possible irradiation of all Ensure surfaces of all workpieces arranged on them is steady.  

This task is accomplished by a workpiece holder solved with the features of claim 1. Advantageous Wei developments of the workpiece holder according to the invention direction are the subject of subclaims 2 to 10. A preferred use of the workpiece holder device Subject matter of claim 11.  

According to the invention is in the workpiece holder device of the type mentioned at least one workpiece holder element provided in the workpiece holder about a secondary axis of rotation lying outside the main axis of rotation a pivot bearing device is rotatably mounted. Hence the workpieces simultaneously rotate around the Main axis of rotation of the workpiece holder device and around Secondary axis of rotation of the workpiece receiving element, which results has that all outer surfaces of the workpieces very evenly, d. H. on average essentially the same Blasting material quantity and the same blasting material speed per Area unit to be processed. Every workpiece is in the blasting cabin rotated in such a way that different Surfaces of this workpiece alternate to the grit accelerator are turned when the workpiece is guided past this at a minimal distance.

In a particularly preferred embodiment of the invention workpiece holding device according to the invention is provided that the workpiece receiving element in one or both rotations directions is rotatable about the secondary axis of rotation and during the Irradiating the workpieces using a pulse transmission from the accelerated blasting material to the workpieces in one turn movement is offset around the respective secondary axis of rotation. This has the particular advantage that no additional drive device for the workpiece receiving element is necessary, which requires additional maintenance and increased The system would be susceptible to failure. As Rotary bearing device for rotatable mounting of the workpiece a suspension bearing is preferably used, in which the workpiece receiving element is hooked in.

In a further preferred development of the invention contemporary workpiece holder, which is special at very small compared to the size of the blasting cabin Workpieces are very advantageous for improved space utilization  effect in the blasting cabinet are on the workpiece neck First, a plurality of hanging bearings 1. Order with associated 1st order secondary rotary axes attached. There is a hanging device on each of these 1st order hangers device for 2nd order hangers with associated secondary rotary axis 2nd order provided, on each of which then a work piece receiving element is mounted. In operation of the plant then the workpiece holder rotates around the Main axis of rotation, the suspension devices with the hangers 2nd order around the associated secondary axes of rotation 1st order and the workpiece receiving elements around the associated secondary rotary axis 2nd order. According to this principle, if necessary, naturally Lich also workpiece holder devices with hanging bearings. 3rd, 4th, ... nth order. Of course You can ver on a workpiece holder divergent suspension devices are attached, the then, depending on the size, in 1st order hangers or in Hängela 2nd, 3rd, ... or nth order can be attached and thus enable optimal use of space.

The basic advantageous difference between the Workpiece holding device according to the present invention extension to the known conventional workpiece holder directions is that at some point all sides the workpieces attached to this "front", d. H. by doing Area in which the workpieces close the beam cone Cut blasting material acceleration device, who blasted the. The greatest radiation energy can be absorbed here and consequently the machining effectiveness is greatest here ten. In comparison to the conventional devices significantly more areas of the side surfaces in this area abundant of blasting material. The radiation energy is on average very evenly over the entire surface of the Workpieces distributed, which can be calculated from the outset and uniform surface appearance.

Especially with very complicated workpieces, such as for example, very rugged, with cavities and Verrip workpieces provided is the work according to the invention Piece holder device of particular advantage. Through the constant rotary movements of the individual workpiece receptacles elements, especially with free storage without external drive with different random rotation speeds and rotation directions, the impinging grains are blasted in ver diverted different directions, so that for blasting material directly from the blasting material acceleration device Areas that are difficult or impossible to access from Blasting material can be reached.

In addition, it is particularly advantageous that due to the additional indirect radiation from rebound and cross racket in the system according to the invention over the conventional system increased number of workpieces can be tet, since the ricochets and ricochets we contribute significantly to the processing of the side surfaces.

The workpiece holder device according to the invention can That is why it is much denser than conventional ones be hung with workpieces because it is no longer necessary is that individual surfaces of the workpieces at the Blasting material accelerator distant passage must be blasted through the beam cone. Shadows of the individual components play against each other from here a significantly lower role than with the known convention workpiece holders.

Using the new type of workpiece holder tion can therefore be a significantly larger volume of the predetermined who use a rotating cylinder (maximum hanger volume) the. The only requirement is that workpieces differ whose workpiece receiving elements do not rotate hinder each other. This allows compared to the conventional workpiece holder devices more parts per Beam path can be processed.

The more effective use of radiation energy for the surface processing of the workpieces has the following further decisive advantages:

• - Due to the possible denser packing of the workpiece holders The device with workpieces reduces the Ver wear of the workpiece holder itself and of Material of the blasting cabin lining, as that in the Blasting cabin blasted to a greater extent the workpieces themselves.
• - The beam times can be compared to conventional Ver drive down to be corrected, which in connection with the higher degree of filling of the blasting cabinet a Ver reduction of blasting material wear is achieved.
• - In addition, the workpiece holder according to the invention tion device that changeover times through convenient Handling when changing the workpiece holder elements can be lowered. Because the suspension unit (Basic sling) is constantly used and for components change only the workpiece holding elements (single slings) are to be replaced in relation to the conventional one Fewer hanger retention space required.
• - Workpieces after the blasting process on the workpiece Bracket device leave the blasting cabin Blasting material left on or in them at the same time from the blasting machine. This blasting material must be operated by the operator Personnel removed from and from the parts and into the system be brought back. The effort for this is reduced in the workpiece holder device according to the invention in that the constant rapid rotary movement of the Parts of the workpiece holding elements a large part of the Blasting material already dropped in the blasting cabinet becomes. This is especially the case with complicated and jagged Workpieces of particular importance.

The preferred hanging bearings described above have advantages open storage because of a closed one Do not store the effects of the aggressive blasting material would withstand. The open storage ensures that penetrating into the storage can during the blasting process The blasting material can escape immediately as freely as possible can. To minimize wear on the hanging bearing to achieve, there is the hook ring, the carrier disc and the bearing balls are preferably made of hardened steel. The hanging The bearing is designed to be hung and powered by the energy of the attached blasting material in motion offset workpiece holding element as frictionally as possible loose and not or only slightly disturbed by stray blasting material Allow rotation. To achieve smoothness, are used for the largest possible bearing balls for storage det, which also keeps their number low.

To the amount of blasting material penetrating into the storage box ring and wear on the suspension (e.g. Hooking ring + hook) of the workpiece holder element to mini gieren, the protective rubber tube is pulled down over this gene.

Nonetheless disrupt blasting material bodies penetrating into the storage box the sequence of movements due to the very large storage area chosen apply (these must be large enough to leave gaps between them through which the largest grit particles pass) only a little and only for a short time, since it covers the interior of the storage can due to the bearing ball Treads (= bottom wall of the storage box) in the direction of Bearing axis through the size adapted to the grit size Leave axis opening.

The measure of the remaining free ring-shaped axis opening at the Bottom of the storage box is chosen so that the gap between the bearing axis and the bottom wall edge in any case ß than the diameter of the largest blasting material used is.

In the construction principle of the workpiece holder according to the invention device with smooth-running, freely rotating movement These are attached to the attached work the first time they enter the beam cone Impulse transmission from the incident blasting material to the Workpieces set in a rotary movement, which during the Blasting process with constant acceleration and deceleration is maintained. These irregular circular movements leave the workpieces in different jets different speed and different Enter and exit the jet cone in the direction of rotation. Thereby is advantageously a particularly uniform surface reached the quality of the workpieces.

Further advantageous developments and embodiments of the workpiece holding device according to the invention result from the exemplary embodiments explained below in conjunction with FIGS. 1 to 9. The figures show:

Fig. 1 is a schematic representation of a vertical section through an embodiment of the workpiece holding device according to the invention,

Fig. 2 is a schematic representation of a horizontal section through a shot blasting machine with the workpiece holding reasoning apparatus according to the embodiment of Fig. 1,

Fig. 3 is a schematic representation of a top view of a further embodiment of the embodiment of Fig. 1,

Fig. 4 is a schematic representation of processing of a vertical section through a conventional Werkstückhalterungsvorrich,

Fig. 5 is a schematic representation of a horizontal section through a shot blasting machine with a conventional workpiece holding device,

Fig. 6 is a schematic representation of a side view of egg ner conventional monorail blasting machine,

Fig. 7 is a schematic representation of a top view of a conventional overhead conveyor blasting machine,

Fig. 8 is a schematic representation ment of a vertical section through a first preferred embodiment of a bearing box for rotatably supporting a Werkstückaufnahmeele,

Fig. 9 is a schematic representation ment of a vertical section through a second preferred embodiment of a bearing box for rotatably supporting a Werkstückaufnahmeele,

Fig. 10 is a schematic representation of a vertical section through an embodiment of the workpiece holder device according to the invention, which has only one workpiece receiving element and

Fig. 11 is a schematic representation of a plan view of an embodiment of the workpiece holding device according to the invention, the hanging bearings 1st and 2nd order.

In the figures, the same or equivalent parts are always provided with the same reference numerals.

The workpiece holder 1 of Fig. 1 is provided for a monorail blasting system and has a suspension unit 17 with a central, vertical central rod 40 , at the upper end of which a hooking ring 41 is arranged for hooking into a monorail 34 . Below the Einhakrin ges 41 extend from the upper end region of the central rod 40 starting at least two support rods 42 radially (e.g. horizontally) in different directions, outwards, at the outer ends of which a pivot bearing device designed as a hanging bearing 18 is fastened.

At each hanger 18, a workpiece receiving member 9 is provided, which consists essentially of a the hanger 18 mounted perpendicular Achstange 43 and a plurality of (horizontal z. B.) of the substantially radially outwardly extending workpiece holders 44, in which the workpieces 3 secured can be.

Each of the axle rods 43 is fixed with its lower end in a retaining ring 45 , which is arranged at the outer end of an outgoing from the central rod 40 , essentially horizontally extending bearing rod 46 . This fi xation prevents the workpiece receiving elements 9 from starting to oscillate laterally during operation of the blasting system.

The workpiece holder 1 described above is, as indicated in Fig. 2, rotated in the blasting cubicle 4 by means of the drive means 7 about a substantially in the central rod 40 extending main axis of rotation 8, for example in the direction indicated by arrow 47 . By pulse transmission from the blasting material acceleration device 5 into the blasting cubicle 4 onto the workpieces 3 , the blasting material is thrown, each workpiece receiving element 9 is rotated (indicated by the arrows 14 ) about an essential rotation axis 10 , 11 , 12 lying in the associated axis rod 43 , 13 brought. The directions of rotation of the workpiece receiving elements 9 (indicated by the arrows 14 ) are, provided the hanging bearings are designed freidre accordingly, arbitrary and random and can be different from each other.

It is also possible, however, that the workpiece holder elements 9 have power transmission coupling elements and are connected to at least one drive device during operation of the blasting system via power transmission means coupled to them, by means of which they move in a defined rotary motion about the respective secondary rotational axis 10 , 11 , 12 , 13 are offset.

The workpiece support device 1 shown in Fig. 1, as shown in Fig. 2, with four, as shown in Fig. 3 shows ge be equipped with three or any other number of workpiece receiving elements 9. It must only be ensured that the workpiece material 9 with the suspended workpieces 3 does not interfere with each other in their rotation. The number of workpiece receiving elements 9 is thus only the size and shape of the workpieces 3 to be machined and the size of the blasting cabinet 4 or the size of the available blasting space to adapt.

In Fig. 10, an embodiment of a workpiece holding device 1 is shown, which corresponds in principle to that of FIG. 1. The only difference is that only a single workpiece receiving element 9 is provided here. In order to ensure a "round" the course of the work piece holder device 1, in this pickup element with respect to the Werkstückauf 9, a counterweight is attached 50th

The workpiece holder 1 of FIG. 11 has a plurality of 1st order hanging bearings 52 attached to support rods 42 with associated 1st order secondary axes of rotation. On the 1st order hangers 52 a suspension device 51 for 2nd order hangers 53 with associated secondary axes of rotation 2nd order is provided, on each of which a workpiece receiving element 9 is then suspended. In addition, 42 further suspension bearings 18 are arranged between two 1st order hangers 52 on support rods 42 , to each of which a workpiece receiving element 9 is then hung directly. In operation, the plant then the workpiece support device 1, the suspension devices 51 like 2nd order 53 1st order and the workpiece-receiving elements 9 rotating about the main axis of rotation 8, with the Hängela to the associated side rotation axes by the associated secondary axes of rotation. 2 Order. Likewise, the workpiece receiving elements 9 arranged between the suspension devices 51 on the hanger bearings 18 rotate about their secondary axes of rotation 10 , 11 , 12 , 13 . As already mentioned above, according to this principle, workpiece holder devices 1 with 3rd, 4th, ... and n-th order hangers can of course also be constructed with Be. Likewise, then depending on the size directly into hanger 1st order 52 or hanger 2, 3, ... or order n ter-able on a workpiece mounting device 1 ver different workpiece-receiving elements 9 be mounted, can be suspended, thereby allowing an optimum use of space . This construction principle is particularly advantageous in the case of workpieces 3 which are very small in comparison to the size of the blasting cubicle 4 and permits improved use of space in the blasting cubicle 4 .

The Hängela ger 18 shown in FIG. 8, preferably used for the workpiece holder devices 1 described above, has a storage box 19 which can be fastened, for example, to the end of a holding rod 42 . In the bottom wall 20 of the bearing box 19 , an axis opening 21 is hen hen, through which a bearing axis 22 is guided from below the bearing box 19 into this. In the bearing box 19 , bearing balls 23 are arranged around the bearing axis 22 on the bottom wall 20 , on which a carrier disk 24 attached to the bearing axis 22 rests from above. The carrier disk 24 is for example attached to the bearing shaft 22, and with means of a lock nut 48 which is screwed onto a thread 49 on the bearing shaft 22 is fixed. Outside the storage box 19 , a fastening means 25 in the form of a hooking ring for the workpiece receiving element 9 (individual hangers) is provided on the bearing axis 22 .

The entire storage box 19 is laterally surrounded by a rubber protection tube 29 which extends down over the hook ring. This protective rubber tube 29 protects the suspension 18 from excessive wear by blasting material.

The storage box 19 is closed from above with a removable Ver closure cap as the top wall 30 , which, for example, consists of plastic and is covered with a gravel layer 31 as wear protection.

So that blasting material that has penetrated into the storage box 19 can run off again without hindrance, the bottom wall 20 is inclined downwards in the course of the side wall 26 of the storage box 19 toward the axis opening 21 and the smallest diameter of the axis opening 21 is larger than the largest diameter the bearing axis 22 in the area of the axis opening 21 plus 2 times the diameter of the largest grit shot used.

In a further improved hanging bearing 18 (see FIG. 9), the side wall 26 of the storage box 19 extends beyond the bottom wall 20 downwards in the direction of fastening means 25 . Furthermore, an inner protection ring 27 and between the inner protection ring 27 and the fastening means 25 on the side wall 26, an outer protective ring 28 is provided between the bottom wall 20 of the bearing box 19 and the fastening means 25 on the ger axis 22 within the side wall 26 . The outer diameter of the inner protective ring 27 and the inner diameter of the outer protective ring 28 are dimensioned such that the smallest distance between the inner protective ring 27 and the side wall 26 and the smallest distance between the outer protective ring 28 and the bearing axis 22 is larger than the diameter of the largest grit material used and that the bottom wall 20 and the inner protective ring 27 and this and the outer protective ring 28 overlap each other. This arrangement of inner protective ring 27 and outer protective ring 28 serves as a barrier for blasting material.

For protection against excessive wear due to the ingress into the bearing box 9 blasting all the free surfaces in the hanger 18 of FIG. Within the bearing socket 19, for. B. the tops of the carrier plate 24 , the safety nut 48 , the inner protective ring 27 and the outer protective ring 28 , inclined so that the beam penetrating into the storage box 19 immediately runs off and runs downwards out of the storage box 19 .

Reference list

1

Workpiece holder

2nd

Shot blasting machine

3rd

workpiece

4th

Blasting cabin

5

Blasting material acceleration device

7

Drive means

8th

Main axis of rotation

9

Workpiece receiving element

10th

,

11

,

12th

,

13

Secondary axis of rotation

14

Direction of rotation

17th

Suspension unit

18th

Hangers

19th

Storage box

20th

Bottom wall

21

Axle opening

22

Bearing axis

23

Bearing ball

24th

Carrier disc

25th

Fasteners

26

Side wall

27

Inner protection ring

28

Outer protection ring

29

Protective rubber tube

30th

Ceiling wall

31

Gravel layer

32

Bucket elevator

33

Blasting material bunker

34

Monorail

35

Shadowing

36

central suspension axis

37

Beam cone

38

strongly blasted side surface

39

weakly blasted side surface

40

Center bar

41

Hook ring

42

Handrail

43

Axle rod

44

Workpiece holder

45

Retaining ring

46

Bearing rod

47

Direction of rotation

48

Security nut

49

thread

50

Counterweight

51

Hanger

52

Hanger 1st order

53

2nd order hangers

Claims (11)

1. workpiece holder device ( 1 ) for a blasting system, during its operation in a blasting cubicle ( 4 ) workpieces ( 3 ) are blasted with blasting material which is thrown into the blasting cubicle ( 4 ) by means of at least one blasting material acceleration device ( 5 ),
the workpiece holding device ( 1 ) having a main axis of rotation ( 8 ) lying in the blasting cabin ( 4 ) and being rotatable about it,
and being provided on the workpiece holding device (1) at least one rotary bearing device for a workpiece receiving member (9) with a ne outside the main axis of rotation (8) and in the Strahlkabi adjacent to axis of rotation (10, 11, 12, 13) so that the Werksückaufnahmeelement (9 ) is rotatably mounted in the blasting cabinet ( 4 ) about the secondary axis of rotation ( 10 , 11 , 12 , 13 ), and workpieces ( 3 ) attached to the workpiece receiving element ( 9 ) are in operation in the blasting cabinet ( 4 ) simultaneously around the main axis of rotation ( 8 ) and the secondary axis of rotation ( 10 , 11 , 12 , 13 ). 2. workpiece holder device ( 1 ) according to claim 1, characterized in that the rotary bearing device allows a free rotation of the workpiece receiving element ( 9 ) in one or both directions of rotation about the secondary axis of rotation ( 10 , 11 , 12 , 13 ) and that the workpiece receiving element ( 9 ) during the irradiation of the workpieces ( 3 ) by means of pulse transmission from the accelerated abrasive material to the workpieces ( 3 ) in a rotary movement about the secondary rotary axis ( 10 , 11 , 12 , 13 ). 3. workpiece holding device ( 1 ) according to claim 1 or 2, characterized in that a single workpiece receiving element ( 9 ) is provided as a single hanger, which is suspended from a single suspension unit ( 17 ), and that the individual hanger by means of at least one as a hanging bearing ( 18 ) trained pivot bearing device on the suspension unit ( 17 ) is rotatably mounted. 4. workpiece holder device ( 1 ) according to one of Ansprü che 1 to 3, characterized in that on the secondary axis of rotation ( 52 ) at least one suspension device ( 51 ) is provided, on which at least one other Ne axis of rotation ( 53 ) is provided, on the at least one workpiece suspension element ( 9 ) is suspended. 5. workpiece holding device ( 1 ) according to one of Ansprü che 1 to 4, characterized in that
the pivot bearing device is formed as a hanging bearing ( 18 , 52 , 53 ) and has a bearing box ( 19 ), in the bottom wall ( 20 ) of which an axis opening ( 21 ) is provided, through which a bearing axis ( 22 ) from below the bearing box ( 19 ) into which it is led,
that bearing balls ( 23 ) are arranged in the bearing box ( 19 ) around the bearing axis ( 22 ) on the bottom wall ( 20 ), on which a carrier disc ( 24 ) attached to the bearing axis ( 22 ) rests from above,
that outside the storage box ( 19 ) on the bearing axis ( 22 ) is provided a fastening means ( 25 ) for a single sling. 6. workpiece holder device ( 1 ) according to claim 5, characterized in that the bottom wall ( 20 ) in the course of the side wall ( 26 ) of the bearing box ( 19 ) to the axis opening ( 21 ) is inclined downwards and that the smallest diameter of the axis opening ( 21 ) is larger than the largest diameter of the bearing axis ( 22 ) in the area of the axis opening ( 21 ) plus two times the diameter of the largest grit particles used. 7. workpiece holder device ( 1 ) according to claim 6, characterized in that all free surfaces within the storage box ( 19 ) are inclined so that in the storage box ( 19 ) penetrating beam immediately down again and out of the storage box ( 19 ) runs out. 8. workpiece holder ( 1 ) according to one of Ansprü che 5 to 7, characterized in that
the side wall ( 26 ) of the storage box ( 19 ) extends beyond the bottom wall ( 20 ) downwards in the direction of the fastening means ( 25 ),
that an inner protective ring ( 27 ) is provided between the bottom wall ( 20 ) of the storage box ( 19 ) and the fastening means ( 25 ) on the bearing axis ( 22 ) within the side wall ( 26 ),
that between the inner protective ring ( 27 ) and the fastening means ( 25 ) on the side wall ( 26 ) an outer protective ring ( 28 ) is provided, and
that the outer diameter of the inner protective ring ( 27 ) and the inner diameter of the outer protective ring ( 28 ) is dimensioned such that the smallest distance between the inner protective ring ( 27 ) and the side wall ( 26 ) and the smallest distance between the outer protective ring ( 28 ) and the bearing axis ( 22 ) is greater is than the diameter of the largest grit particles used and that the bottom wall ( 20 ) and the inner protective ring ( 27 ) as well as this and the outer protective ring ( 28 ) overlap each other. 9. workpiece holder device ( 1 ) according to one of Ansprü che 5 to 8, characterized in that the entire storage box ( 22 ) is laterally enclosed by a protective rubber tube ( 29 ). 10. workpiece holder ( 1 ) according to one of Ansprü che 5 to 9, characterized in that on the ceiling wall ( 30 ) of the storage box ( 19 ) a cover gravel layer ( 31 ) is provided. 11. Use of a workpiece holder device ( 1 ) according to one of claims 1 to 10 in a monorail blasting system for surface processing of metal castings.