EP1526198B1 - Heald frame with novel corner connector - Google Patents

Description

The invention relates to a weaving shank for weaving machines.

Heald frames are used on weaving machines for example for shedding. They have an upper and a lower shaft rod, which are connected at their ends by side supports. The upper and the lower Shaft rods are provided with hanger bars on which the healds are held in parallel to each other in large numbers. When setting up the weaving machine, for example, due to article change, healds must occasionally be taken out of the machine. It is also necessary, for example, to change the healds to disassemble the heald by the side supports are removed from the shaft rods.

In high-performance looms, the heald is subject to a strong vibration load. This must not lead anywhere in the heald, not even at the ends of the heald, to material cracks, vibration breaks and the like:

The design of the connection between the side supports and the shaft rods has been the object of various optimization attempts in the past:

From the DE 196 12 404 A1 For example, a heddle with releasable corner joints between the side support and the shaft rod is known. At each corner joint a corner connector is used in the cavity in question, which is riveted to the side wall of the formed in the shaft rod cavity. In a recess of the corner connector enters a provided on the side support pin-like projection, which is secured in this recess by a clamping screw. After loosening the clamping screw, the side support can be removed.

The same document discloses in a further embodiment, a corner joint, wherein the pin-like Projection is provided with an elastic bearing member which engages over the flat pin on its top, on its front and on its underside. The bearing part 14 is intended to damp vibration.

From the DE 198 58 013 C2 is a connection between shaft rod and side support in heddles with riderless shaft-strand system known. To the compound includes a inserted into the cavity of the shaft rod connector with a recess for receiving a pin provided on the side support. This pin carries an intermediate piece of plastic and engages with this in said recess. A longitudinally passing through the pin fastening screw finds its anchorage in a threaded piece, which sits in the inserted into the cavity of the shaft rod connector. The connecting piece has a certain mobility in the cavity in the lateral support longitudinal direction, being supported in one direction by two compression springs. At the top it is supported by a screw, with the exact position of the connector is adjustable. With this measure, the play of leashes can be adjusted.

At high operating speeds of looms healds are greatly accelerated and slowed down, so that in particular in the region of the joints between the side supports and the shaft rods large forces occur. These must not cause any damage to the side supports or the shaft rods. Here, in particular the pin longitudinally penetrating screws or the side wall of the shaft rod through rivets have proven to be weak points. Furthermore, a corner joint be as easy to manufacture and require no special tools.

On this basis, it is an object of the invention to provide a heddle for weaving machines, which can be quickly and easily assembled and disassembled and thereby has a high load capacity.

This object is achieved with the weaving shaft according to claim 1:

The weaving shank according to the invention has a connecting piece which can be inserted into the cavity of the shaft rod which is open at the end and can be fastened there in a latching manner. It is literally clipped, which requires neither special knowledge nor special tools. E-link connections can thus be made quickly and easily. If the connector is made of plastic, it can exert damping effect at the same time. It can be manufactured as a one-piece plastic injection molded part, resulting in low production costs.

Preferably, the connecting piece between two webs of the shaft rod is engaged. In addition, it preferably transmits the driving forces from the side supports on the shaft rod areally on the webs. As a result, a low shaft rod load and a high fatigue strength is achieved. To make the corner joint no special tools or special knowledge are required.

The connecting piece is held in place with respect to the longitudinal direction of the shaft rod by the latching lug. The Power transmission can be moved by contact surfaces of the intermediate piece, which are arranged adjacent to the latching lug. On the opposite side is preferably provided as a means for supporting the connecting piece, a spring means. In addition, here a clamping piece can be used, which is provided with an externally actuated clamping screw and presses against the locking lug opposite side of the connector to clamp this. The clamping piece has on its upper side a contact surface for the inside of the web of the shaft rod and a threaded bore in which the clamping screw is seated. The power transmission takes place over a large area.

In a preferred embodiment, the connector on the pin encompassing holding pieces, which are provided at their ends with spring means. These form a resilient system for the side support, which increases the vibration resistance of the connection and is otherwise considered advantageous.

Further, it is considered advantageous if the latching opening is a passage opening through which the latching lug is visible from the outside. This has the advantage that, for example, differently colored connectors can be kept ready and that from the outside can be seen at a glance, which color has the connector. If dimensionally differently designed connectors are available, for example, set different Litzenspiele, the establishment of looms is much easier. For example, with short shanks, connectors can be used, the lower litz games adjust while in long shafts different colored connectors may be present, the greater Litzenspiele set. Preferably, a supply of different connectors is kept ready. In the stock, connectors of the same color have the same dimensions and connectors of different colors have different dimensions.

It is also possible to use uniform connecting pieces and to provide an intermediate piece between the pin and the connecting piece. This may have special damping properties or spring properties. In addition, as explained above with regard to the connecting pieces, the intermediate pieces can be kept ready in different colors and different dimensions, in order in turn to set different strand play. This is true regardless of how the connector is mounted in the shaft rod.

Also, regardless of the concrete formation of the connection between the connecting piece and the shaft rod, it is considered expedient if the connecting piece or the intermediate piece is designed so that they keep the pin away from the side walls of the shaft rod. This can be done by positive engagement between the connecting piece or the intermediate piece on the one hand and the pin on the other hand, wherein the pin in the transverse direction (measured perpendicular to the side walls of the shaft rod) is thinner than the inside diameter of the cavity. The connector and / or the intermediate piece, however, is supported on the side walls of the cavity and thus holds the pin from the side walls of the shaft rod away. Preferably, the pin is centered in the cavity.

In summary, for the embodiments of the invention, the following advantages can be stated, which apply individually or cumulatively, depending on the design:

Due to the specified options for adjusting the heald play, the clamping of strands on the mounting rail can be prevented. In addition, strand breaks, skew the strand or Kettfadenbrüche can be prevented. Furthermore, with the need-based adjustment of the heddle play, the wear on mounting rails and strands as well as the noise emanating from the shaft can be reduced. In addition, manufacturing tolerances can be compensated or corrected. It is possible to adapt the Litzenspiels to the shaft length. The holding pieces, if they are made of plastic, have a low weight and they can have a vibration-damping effect. The corner joint has a certain mobility, which counteracts vibration fractures. The replacement of the connectors, for example, for Litzenspielverstellung or repair is possible without special tools thanks to the locking connection in a simple manner.

The locking connection between the connecting piece and the shaft rod, the position of the connector is set correctly. After engaging the connector, the associated mounting screw can be tightened without further adjustment. It is not a special tool, such as a torque wrench required. The side support does not need a cross hole, which recommends the heald of the invention especially for high-performance weaving machines. The production costs are low. The connection does not require expensive screw connections, riveting or gluing, as well as very few individual parts.

Figur 1

einen Webschaft in schematisierter Vorderansicht,

Figur 2

den Webschaft nach Figur 1 in einer ausschnittsweisen, teilweise geschnittenen Darstellung in einem anderen Maßstab,

Figur 3

ein Zwischenstück der aus Figur 2 hervorgehenden Eckverbindung in gesonderter Darstellung,

Figur 4

eine abgewandelte Ausführungsform eines Webschafts in ausschnittsweiser, teilweise geschnittener Darstellung,

Figur 5

ein Verbindungsstück des Webschafts nach Figur 4 in Vorderansicht,

Figur 6

das Verbindungsstück nach Figur 5, geschnitten entlang der Linie VI-VI,

Figur 7

den Webschaft nach Figur 4, geschnitten entlang der Linie VII-VII,

Figur 8 bis 10

Verbindungsstücke für Webschäfte in unterschiedlichen Ausführungsformen, jeweils in Seitenansicht,

Figur 12

unterschiedliche Ausführungsformen von Zwischenstücken für Webschäfte und zum Einsatz in entsprechenden Verbindungsstücken, jeweils in schematisierter Darstellung,

Figur 13

unterschiedliche Ausführungsformen von Zapfen und Zwischenstücken bzw. Verbindungsstücken, jeweils entsprechend der Schnittdarstellung gemäß Figur 7,

Figur 14

unterschiedliche Ausführungsformen von Seitenstützen und deren Haltezapfen in jeweils schematisierter Seitenansicht und

Figur 15

einen Satz Zwischenstücke für unterschiedliche Litzenspiele in schematisierter Seitenansicht.

Further details of advantageous embodiments of the invention will become apparent from the drawings, the accompanying description or claims. In the drawings, embodiments of the invention are illustrated. Show it:

FIG. 1

a weave in a schematic front view,

FIG. 2

following the weave FIG. 1 in a partial, partially sectioned representation on a different scale,

FIG. 3

an intermediate piece of the FIG. 2 emerging corner joint in a separate representation,

FIG. 4

a modified embodiment of a weave in a sectional, partially sectioned representation,

FIG. 5

a connector of the weave post FIG. 4 in front view,

FIG. 6

the connector after FIG. 5 , cut along the line VI-VI,

FIG. 7

following the weave FIG. 4 , taken along the line VII-VII,

FIGS. 8 to 10

Connecting pieces for heddle shafts in different embodiments, in each case in side view,

FIG. 12

different embodiments of spacers for heddle shafts and for use in corresponding connectors, each in a schematic representation,

FIG. 13

different embodiments of pins and spacers or connecting pieces, each according to the sectional view according to FIG. 7 .

FIG. 14

different embodiments of side supports and their retaining pins in each case schematic side view and

FIG. 15

a set of spacers for different Litzenspiele in a schematic side view.

In FIG. 1 a heald 1 is illustrated, to which an upper shaft rod 2, a lower shaft rod 3 and two side supports 4, 5 belong. The shaft rods 2, 3 are connected by the side supports 4, 5 at their ends and thereby held parallel and spaced from each other. Both shaft rods 2, 3 wear, as in the example of the shaft rod 2 FIG. 2 it can be seen, in each case a heddle support rail 6, on which a plurality of strands 7 are held with their end loops.

The out FIG. 1 apparent heald 1 is characterized in particular by the nature of the connection between the shaft rods 2, 3 and the side supports 4, 5. This compound is representative of all four corner joints in FIG. 2 illustrated.

Essential element of the corner joint forms a connecting piece 8, which may be formed by a plastic injection-molded element. It is inserted into a cavity 9 of the shaft rod 2, which is bounded above and below by a web 11, 12 and by side walls 13, 14 and preferably has an approximately rectangular cross-section. The shaft rod 2 may have one or more such cavities. The cross section of the cavity 9 preferably has a width (in FIG. 2 perpendicular to the plane of the drawing), which is much smaller than its height. The height is the distance between the bars 11 and 12. It is in FIG. 2 parallel to the drawing plane in the vertical direction.

The connecting piece 8 is, for example, a shaped body which, on its underside, extends over its entire length Length extending and the width of the web 12 engaging plate or rib 15 has. It goes to its side of the support 5 facing the end in a leg 16, which, as will be seen, for supporting a formed on the side support 5 pin 17 is used. The rib 15 carries at its end remote from the leg 16 a locking lug 18 which projects beyond the lower, the rib 15 delimiting flat surface out down and engages in a formed in the web 12 latching opening 19.

The rib 15 continues, starting from the latching lug 18, with an initially U-shaped and then in the opposite direction C-shaped bent section 21 in the direction of the web 11. In addition, it branches between the locking lug 18 and the leg 16 to extend at right angles to the web 12 in the direction of the web 11. This portion 22 of the rib 15 leads to an upper portion thereof, which in turn forms a leg 23. The legs 16, 23 and the portion 22 thus define a jaw-like receiving opening for the pin 17. Between the portion 22 and the portion 21 is preferably arranged integrally formed with the rib 15 plate 24 for stiffening the connecting piece 8. Above the same, the sections 21, 22 are connected by a short web 25, which defines an opening 27 with the upper part of the section 21 and a spring section 26 of the rib 15. The spring portion 26 is curved in the direction of the web 11 in order to abut against this with a bend 28.

For further connection between the shaft rod 2 and the side support 5 is a clamping piece 29 which is formed by a U-shaped bent metal bracket. His upper, on the web 11 adjacent leg has a threaded bore 31 in which a clamping screw 32 is seated. This is supported with its front end on the lower leg of the clamping piece 29, which rests on the leg 23. It also passes through the upper web 11 at a through hole 33, so that its head 34 is located outside of the shaft rod 2.

The pin 17 is formed substantially disc-shaped. Its measured perpendicular to the plane of the width is less than the clear width of the cavity 9. At its side walls 13, 14 facing flanks it is with flat surfaces 51, 52 (FIG. FIG. 7 ), while it is barrel-shaped or arcuately curved at its legs 16, 23 facing sides. Between the legs 16, 23 and the pin 17 is preferably an intermediate piece 35, the in FIG. 3 is separately illustrated. It has inside the pin 17 adapted and outside the legs 16, 23 and the section 22 adapted contour. In principle, it is Ω-shaped. Its upper leg 36 and lower leg 37 may be the same or as shown in FIG FIG. 3 illustrated, have different heights X, Y. This allows the setting of two different Litzenspiele depending on the orientation in which the intermediate piece 35 is placed on the pin 17. To make this possible, the upper and the lower contour of the pin 17 are preferably formed the same. The free ends of the legs 36, 37 are as shown FIG. 3 can be seen, provided with short in-line projections 38, 39, for adjusting the correct distance between the side support 5 and the shaft rod 2 and at the same time serve as a damping intermediate layer in the gap 41 present here ( FIG. 2 ).

To make the connection between the shaft rod 2 and the side support 5, the procedure is as follows:

As a preparatory measure, the shaft rod 2, if not already done, initially provided with the locking opening 19, in which, the locking opening 19 as FIG. 2 illustrated, in the lower web 12 and, as illustrated by dashed lines, possibly in one of the side walls, for example, the side wall 14 is introduced by means of milling operation. The latching opening 19 is, as far as it passes through the web 12, rectangular. The part extending into the side wall 14 forms a viewing window. The connecting piece 8 is inserted together with the clamping piece 29 in the cavity 9, wherein the spring portion 26 yields downward and the locking lug 18 slides on the web 12 along until it finds in the latching opening 19. Under the action of the spring portion 26, the latching lug 18 engages in the latching opening 19. Then, the pin 17 is provided with the intermediate piece 35 and inserted into the hollow chamber 9. It can now be screwed through the through hole 33, the clamping screw 32 in the threaded hole 31 and tightened so that the leg 23 is pressed firmly against the intermediate piece 35 and thus the pin 17 is clamped.

The intermediate piece 35 is preferably formed from a not too hard, slightly resilient and damping plastic, so that a vibration-absorbing connection between the shaft rod 2 and the side support 5 is provided. The power transmission essentially takes place by means of the webs 11, 12, the clamping piece 29, the pin 17 and the leg 16 instead. A local weakening of the side support 5 or the shaft rod 2 is not recorded.

When disassembling the side support 5, the connecting piece 8 remains in the shaft rod 2. Only to change the Litzenspiels, if no intermediate piece 35 is present, the connector 8 can be replaced by another connector 8 with deviating embodiment. If an intermediate piece 35 is present this is mounted on the pin 17 of the side support 5, or clamped, and is replaced to change the Litzenspiels by another intermediate piece 35 with deviating embodiment.

FIG. 4 illustrates a modified embodiment of the heald 1 and its corner joint. As far as construction or functional equality with the embodiment described above is present, reference is made to the above description without re-explanation on the basis of the same reference numerals. Otherwise, the following applies:

The connecting piece 8 encloses a circular arc-shaped limited pin 17 without the interposition of an intermediate piece. The mouth bounded by the legs 16, 23 and the section 22 follows a circular arc. As in particular from FIG. 5 It can be seen, the free ends of the legs 16, 23 are provided with serving as a bending springs, with a small radius arcuately bent contact portions 42, 43, according to FIG. 4 support the side support 5 resiliently.

Incidentally, the upper spring portion 26 of the connecting piece 8 as the opening 27 is formed in a circular arc. The spring portion 26 forms a detent 18 in the detent opening 19 retaining spring.

In place of the U-shaped clamping piece 29, only an elongated, adjacent to the leg 23 clamping plate 44 is provided, which is mounted with an arcuate end 45 in a corresponding recess of the connecting piece 8. The clamping screw 32 is anchored here in a formed in the upper web 11 threaded bore 46. The web 11 has a substantially greater thickness than the web 12th

A significant feature of the connector 8 goes out FIG. 6 out. On the inner contour of the legs 16, 23 and, if necessary, also on the section 22, a rib 47 is preferably formed centrally, which protrudes into the bounded interior. The function of the same is off FIG. 7 seen. The pin 17 is provided at its outer periphery with a groove 48 which is just so large that it can accommodate the rib 47 play. The measured between its flat sides 51, 52 width of the pin 17 is also substantially smaller than the inside diameter of the cavity 9. The flat sides 51, 52 are thereby held at a distance parallel to the side walls 13, 14. By the rib 47 and its positive connection with the groove 48, the pin 17 is centered between the side walls 13, 14 held without touching them. The rib 47 and the groove 48 thus form a positive-acting means 49 for aligning the pin 17th

The connecting pieces described above each have a latching nose 18 and an associated spring means, for example in the form of the spring section 26. It is, however, as shown schematically in FIG. 8 indicated, also possible to provide two locking lugs 18a, 18b, which are for example held parallel to each other, somewhat resilient legs 53, 54 of the connecting piece 8. As FIG. 9 illustrated, it is sufficient if only one of the legs 53, 54 is provided with the locking lug 18. Further, it is possible to arrange latching lugs on the flanks of the connecting piece 8, as seen from FIG. 10 evident. According to this embodiment, a latching means in the form of a latching tongue 55 may be provided on one or both flat sides of the connecting piece 8, which then engages in a corresponding latching opening in the associated side wall 13 or 14.

FIG. 12 illustrates different embodiments of spacers 35a, 35b, 35c, 35d, 35e, 35f. For example, the spacers can be symmetrical as the intermediate pieces 35a, 35b, 35c, 35d or 35e or alternatively asymmetric as the intermediate piece 35f be formed. The asymmetry consists here in different thicknesses of the legs 36f, 37f. If necessary, it is also possible, as in the intermediate piece 35a, the legs 36a, 37a form as spring elements. For this purpose, the legs 36a, 37a may have an increased thickness and recesses which give the legs 36a, 37a a compressibility in the longitudinal direction of the side support 5.

It is also possible to form the abutment sections 42, 43 differently resiliently, as is the case with the intermediate pieces 35b, 35c, 35d, 35e, with reference to the abutment sections 42b, 42c, 42d, 42e and 43b, 43c, 43d, 43e. It can be achieved by different spring hardness and damping effects.

FIG. 13 illustrated as an alternative to FIG. 7 other ways of designing positive, the pin 17 centering or otherwise away from the side walls 13, 14 means. In the illustrated embodiments, different configurations of legs 16, 23 and 36, 37 (distinguished by letter indices) are shown respectively. For example, the pin 17a, 17b may have a smooth outer peripheral surface. For centering of the pin 17a, for example, fingers 64, 65 resting against the flat sides 51a, 51b are provided, which extend away from the section 22 of the connecting piece 8. It is also possible to provide the legs 16b, 23b and 36, 37 with the flat sides 51b, 52b overlapping edges. The legs 16c, 23c and 36, 37 may also have a trapezoidal cross-section, the pin 17c then a triangular has round running groove. The configuration can also be reversed, as can be seen from the legs 16d, 23d and 36, 37 and the associated pin 17d. Likewise, a circumferential groove extending on the pin 17e or a peripheral rib on the pin 17f may be provided, the legs 16e, 23e and 16f, 23f being respectively complementary.

The pins 17 need not be barrel-shaped or rectangular. It can, like FIG. 14 illustrated, the variously shaped pins 17 g to 17 k are used, which allow a positive connection between them and a correspondingly complementarily shaped intermediate piece 35 or a complementary shaped connector 8.

Another aspect of the invention is the use of a set of connectors 8 having different leg dimensions or, as shown in FIG FIG. 15 shows, a set 66 consisting of spacers 35, 35-1, 35-2, 35-3, the matching outer contours and matching inner contours, but different thicknesses legs 36, 37 have. If, for example, the legs 37-1 to 37-3 behave dimensionally like 1: 3: 5 and the legs 36-1 to 36-3 behave dimensionally as 6: 4: 2, six different clearance dimensions can be set if each intermediate piece 35-1 to 35-3 reversible, that is formed symmetrically inside and outside. The intermediate pieces 35 of the set 66 preferably have different identifying means, such as different colors, different end lengths, etc, whereby the intermediate pieces can be made optically distinguishable by the installation position to recognize at a glance. As the Figures 3 and 15 For example, a notch 50, 50-1, 50-2, 50-3 may be formed in the intermediate piece 35 as identification means, the position of which identifies the leg thicknesses. The same or similar means may be provided on the connector for dimensional marking.

A novel corner connector for heddle shafts has locking means 18, 26, with which it can be held in a shaft rod 2. The load-locking takes place independently of the locking means by a clamping device which acts between the webs 11, 12 of the shaft rod 2.

LIST OF REFERENCE NUMBERS

1

heald

2, 3

stave

4, 5

side supports

6

shaft stave

7

strands

8th

Connecting piece, (holding piece)

9

cavity

11, 12

web

13, 14

side walls

15

rib

16

leg

17

spigot

18

locking lug

19

latching opening

21, 22

section

23

leg

24

plate

25

web

26

spring section

27

opening

28

bend

29

clamp

31

threaded hole

32

clamping screw

33

Through Hole

34

head

35

Intermediate piece, (holding piece)

36, 37

leg

38, 39

projections

41

gap

42, 43

bearing sections

44

clamping plate

45

The End

46

threaded hole

47

rib

48

groove

49

medium

50

score

51, 52

flat sides

53, 54

leg

55

catch tongue

56

Through holes

57

Anchor (threaded bolt)

58

cross hole

59

anchor

61

threaded bolt

62

access opening

63

axis

64, 65

finger

66

sentence

Claims (17)

1. Heald frame (1) for weaving machines,
   with at least one heald frame rod (2), on which a heald support means (6) is provided and which encloses a cavity (9) open at the end with a wall (11, 12, 13, 14), in which a locking opening (19) is configured,
   with at least one side support (5), which is connected to the heald frame rod (2) at its end and extends substantially at right angles thereto and which is provided with a lateral journal (17) extending into the cavity (9),
   with a connection piece (8), which has holding legs (16, 23) engaging around the journal (17) and is held in the cavity (9), which has a catch lug (18) associated with the locking opening (19) and also an element (26), which is arranged opposite the catch lug (18) and is supported against the wall (11, 12, 13, 14).
2. Heald frame according to claim 1, characterised in that the element (26) is a spring element.
3. Heald frame according to claim 1, characterised in that the legs (16, 23) are provided with resiliently configured abutment sections (42, 43) at their ends.
4. Heald frame according to claim 1, characterised in that the locking opening (19) is a passage, through which the catch lug (18) is visible from the outside.
5. Heald frame according to claim 1, characterised in that an intermediate piece (35) is arranged between the legs (16, 23) of the connection piece (8) and the journal (17).
6. Heald frame according to claim 5, characterised in that the intermediate piece (35) has two preferably resilient legs (36, 37) with extensions (38, 39) configured at their end regions.
7. Heald frame according to claim 1, characterised in that the holding legs (16, 23) of the connection or holding piece (8, 35) have positive-locking fastening elements (49), which fixedly hold the journal (17) in relation to a direction at right angles to its flat sides (51, 52).
8. Heald frame according to claim 7, characterised in that the flat sides (51, 52) are spaced parallel from the respectively adjacent wall (13, 14) to form gaps.
9. Heald frame according to claim 7, characterised in that the holding piece is a connection piece (8), which is held in direct connection with the heald frame rod (2).
10. Heald frame according to claim 7, characterised in that the holding piece is an intermediate piece (35), which is held on a connection piece (8), which is itself connected directly to the heald frame rod (2).
11. Heald frame according to claim 1, characterised in that the holding piece (8, 35) is configured asymmetrically and can be inserted into the heald frame rod (2) in two installation positions differing from one another by a rotation of 180°.
12. Heald frame according to claim 11, characterised in that the holding piece is a connection piece (8) held directly in the heald frame rod.
13. Heald frame according to claim 11, characterised in that the holding piece is an intermediate piece (35), which is itself held in a connection piece (8) held directly in the heald frame rod (2).
14. Heald frame according to claim 1, with a set (66) of different holding pieces (35), from which a holding piece can be selected to be arranged and held in the cavity (9) and which has holding legs engaging around the journal (17) and fixedly holding the journal (17), wherein the holding pieces (35-1, 35-2, 35-3) of the set (66) define different holding positions for the journal (17).
15. Heald frame according to claim 14, characterised in that the holding piece (35) is a connection piece (8) held directly in the heald frame rod (2).
16. Heald frame according to claim 14, characterised in that the holding piece (35) is an intermediate piece (35-1, 35-2, 35-3), which is itself held in a connection piece (8) held directly in the heald frame rod (2).
17. Heald frame according to claim 14, characterised in that the holding pieces (35) of the supply set (66) are made of plastic, wherein holding pieces with the same dimensions have the same characterising elements and holding pieces with different dimensions have different characterising elements.

Images