Chain link, conveying chain and chain conveyor

Abstract

The invention relates to a chain link (1) for a chain conveyor for conveying small parts (17), in particular bottle closures, having a, in particular flat, support surface for small parts, wherein means (3) for fitting at least one carrier (14) are provided on opposite sides of the chain link. This allows the small parts to be conveyed without damage, on the other hand, the chain link (1) can be easily adapted to different types of small parts that differ in diameter and/or height. At least two carriers (14) are provided, each of which has a fastening part (15) which can be attached to a means (3) for fitting, and a gripping part (19) which is made of a softer material than the fastening part (15) and has one or more extensions (16) which, when the carrier (14) is in the fitted state, are aligned towards the respective other carrier (14).

Claims

1. A chain link for a chain conveyor for conveying small parts, in particular bottle closures, having a, in particular flat, support surface (2) for small parts, wherein means for fitting at least one carrier are provided on opposite sides of the chain link, wherein at least two carriers are provided, each having a fastening part which can be fitted onto a means for fitting, and a gripping part, which is made of a softer material than the fastening part and has one or more extensions which, when the carrier is in the fitted state, are directed towards the respective other carrier.

2. The chain link according to claim 1, wherein the means for fitting a carrier are formed as wing-like projections which are aligned transversely to a conveying direction of the chain link.

3. The chain link according to claim 1, wherein the means for fitting have a toothing.

4. The chain link according to claim 1, wherein on the side of the chain link facing away from the support surface at least one head part is provided as well as one fork part with two legs opposite the head part in the conveying direction, wherein the fork part is designed such that the head part of a chain link can be inserted between the legs of the fork part of a following chain link.

5. The chain link according to claim 4, wherein the head part and the fork part, in particular its legs, have openings for accommodating a chain pin for the articulated connection of two chain links.

6. The chain link according to claim 4, wherein the head part has a cavity for accommodating a traction piece rotatable in the cavity, wherein an axis of rotation of the traction piece normal to the conveying direction of the chain link, in particular normal to the support surface, is defined by the design of the cavity, and wherein the openings in the head part are designed as elongated holes aligned in the conveying direction in order to define a maximum angle of rotation.

7. The chain link according to claim 6, wherein a traction piece is additionally provided which is guided and rotatable in the head part and has a bore normal to its axis of rotation, which is aligned with the openings of the head part, namely the elongated holes.

8. The chain link with carriers according to claim 1, wherein the fastening part is designed for displacement on the means for fitting.

9. The chain link with carriers according to claim 8, wherein retaining bars serving as guide rails for the means for fitting are provided on the fastening part.

10. The chain link with carriers according to claim 1, wherein the fastening part has an actuating means for displacement on the means for fitting.

11. The chain link with carriers according to claim 1, wherein the fastening part is designed to latch onto the means for fitting.

12. The chain link with carriers according to claim 1, wherein the gripping part has a plurality of finger-shaped or lobe-shaped extensions of elastic material for holding small parts.

13. The chain link with carriers according to claim 1, wherein gripping part has or forms exactly one extension of elastic material for holding small parts, which extension is designed to contact a small part with at least one flat boundary surface in the fitted state of the carrier.

14. The chain link with carriers according to claim 1, wherein the gripping part has exactly one curved extension of elastic material for holding small parts, which extension is designed to at least partially enclose a small part with its curvature in the fitted state of the carrier.

15. The chain link with carriers according to claim 1, wherein the gripping part is made of one piece.

16. The chain link with carriers according to claim 1, wherein the fastening part and the gripping part are manufactured in one piece by a common manufacturing process, such as a two-component injection molding process.

17. The chain link with carriers according to claim 1, wherein the carriers are pretensioned in the fitted state towards the respective opposite carrier by spring elements.

18. A conveyor chain comprising a plurality of successive chain links according to claim 1.

19. The conveyor chain according to claim 18, wherein the chain links are formed and in each case a head part of one chain link is connected to the fork part of the following chain link by means of a chain pin.

20. The conveyor chain according to claim 19, wherein the chain links additionally have a traction piece, which is guided and rotatable in the head part, wherein a chain pin is located in the bore of the traction piece.

21. The chain conveyor comprising a conveyor chain according to claim 18 and at least one drive.

22. The chain conveyor according to claim 21, wherein chain guide profiles are provided at least in sections on both sides of the conveyor chain parallel to the conveying direction, on which profiles the conveyor chain rests with its means for fitting of at least one carrier.

23. The chain conveyor according to claim 21, comprising chain links and carriers, wherein displacement means, in particular links which are fixed relative to the conveyor chain, are provided, with which the actuating means can be contacted for displacing the carriers along the means for fitting.

24. The chain conveyor according to claim 23, wherein the displacement means are adjustable transversely to the conveying direction in order to be able to set a predetermined distance between two opposite carriers of a chain link.

25. The chain conveyor according to claim 23, wherein the distance between the conveyor chain and displacement means is adjustable to ensure engagement between the displacement means and carriers of different heights.

26. A use of a chain conveyor according to claim 21 for conveying closures, in particular bottle closures, made of plastic or metal.

27. The chain link according to claim 1, wherein a groove is provided in a center of the support surface in a conveying direction, so that at the end of a conveying section, a removal wedge or a removal blade can engage in the groove in the conveying direction and small parts can be pushed straight on over the removal wedge or the removal blade.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) The invention is now explained in more detail by means of embodiment examples. The drawings are exemplary and are intended to illustrate the idea according to the invention, but in no way restrict or even conclusively represent it, wherein:

(2) FIG. 1 shows an exploded view of a chain link from the front and below;

(3) FIG. 2 shows an exploded view of a chain link from the side and above;

(4) FIG. 3 shows an exploded view of a chain link from the side and below;

(5) FIG. 4 shows a longitudinal section, front view and top view for a chain link according to FIGS. 1-3;

(6) FIG. 5 shows a bottom view, cross-section in conveying direction, front view and top view of a carrier;

(7) FIG. 6 shows a side view, cross-section normal to the conveying direction and cross-section parallel to the conveying plane of a carrier;

(8) FIG. 7 shows a conveyor chain with closures in perspective;

(9) FIG. 8 shows a cross-section through a chain conveyor;

(10) FIG. 9 shows a displacement means (link) with adjusting element of a chain conveyor in perspective view;

(11) FIG. 10 shows a perspective view of a chain conveyor;

(12) FIG. 11 shows a chain link in front view with a flat small part (closure);

(13) FIG. 12 shows a chain link in front view with a medium-high small part (closure);

(14) FIG. 13 shows a chain link in front view with a high small part (closure);

(15) FIG. 14 shows a chain link with spring elements, with the carriers in the maximum open position, shown in cross-section, in partially cut side view and top view;

(16) FIG. 15 shows the chain link from FIG. 14, with the carriers in the closed position;

(17) FIG. 16 shows the chain link from FIG. 14, with the carriers in a possible holding position;

(18) FIGS. 17 to 22 show different embodiments of gripping parts for carriers.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(19) FIGS. 1 to 4 show a chain link 1 according to the invention. Each chain link 1 has three openings 8 for the chain pin 9, especially in the form of bores. An elongated hole 13 in the narrower head part 5, and two holes in the fork section 6, which are in alignment as good as possible, here one in each leg 7 of the fork section 6. In the head part 5, where there is an opening in the form of an elongated hole 13, the chain link 1 has a cavity 10 on the underside to accommodate the traction piece 11.

(20) In the central area, chain link 1 has two wing-like projections 3 on the upper side, one each orthogonally projecting to the left and to the right as seen in conveying direction 12. The upper side of the projections 3 lies here in the same plane as the support surface 2, the upper side of the projections 3 and the support surface 2 form the conveying plane. These projections 3 serve on the one hand to be able to fit a sliding guide under these projections 3, which can form a guide across the width of the projections 3, can support the entire projection 3 downwards in each case and can carry the weight of the conveyor chain formed by the chain links 1 together with the material being conveyed. This sliding guide can be formed by chain guide profiles 20, see FIG. 8. On the other hand, these projections 3 are used for fastening and accommodating carriers 14, which can be designed in different ways. By means of a latching portion, such as a toothing 4, they allow carriers 14, which can also be designed in a toothed manner, to be fitted (snapped on) in different positions but fixed in position after fitting. However, the toothing 4 or the snap-on area does not extend to the outside end of the projection 3 but ends just before it. Also, the toothing 4 ends shortly before the central body area of the chain link 1, i.e. shortly before the support surface 2 for the small parts. Toothing 4 is provided on both mutually parallel flanks of each projection 3, both on the flank oriented in the conveying direction and the flank oriented against the conveying direction. The toothing 4 is located on both flanks and extends in the height direction preferably from the center of the flank to the underside of the projection 3.

(21) From the center of the flank to the top side, the latching portion is surmounted by an untoothed protrusion 22 which engages in a retaining bar 24 on the fastening part 15 of the carrier 14 which serves as a guide rail.

(22) Ribbing can reinforce chain link 1 to absorb all forces.

(23) The traction piece 11, which is inserted from below into the front part of chain link 1, i.e. the head part 5, serves on the one hand as a joint to ensure changes in the direction of movement of chain link 1 in the horizontal plane, and on the other hand for an almost play-free connection of individual chain links 1 via the fork part 6 and the chain pin 9 to the following chain link 1 and in this form for the optimum introduction of the forces occurring during the movement of the conveyor chain from the preceding chain link 1 to the following one. The minimum radius in which the traction piece 11 allows a change of direction is defined by the geometry of the chain link 1 and the attached carriers 14.

(24) Traction piece 11 can be made of the same material as chain links 1, or it can be made of a different material but with very similar other properties to reduce friction and noise. Polyamide (PA) is preferably used for the traction piece 11, alternatively POM or other plastics with similarly good strength properties could be used.

(25) If required, any type of carrier 14 can be attached to the chain links 1, in particular snapped onto them. There is a need if a lateral guide is necessary for the material to be conveyed. The advantage of fitted carriers 14 as guides is that they travel with the material to be conveyed, and thus there is no relative movement between the material to be conveyed and the lateral guide, as is the case with other, fixed guides. No relative movement means no friction, no rubbing, no abrasion, no angel hair as with air conveyors. However, there may also be a need if the conveying direction 12 deviates from the horizontal and firstly the frictional force transmitted on the support surface 2 is no longer sufficient to move the material to be conveyed further, or secondly the material to be conveyed would even tip or fall off the conveying surface due to gravity. In this case, the carriers 14 provide additional propulsion and prevent the material being conveyed from tipping or coming loose from chain link 1 by clamping.

(26) It is intended that preferably always two carriers 14 are fitted to each individual chain link 1. To be more precise, one carrier 14 is fitted to each of the two projections 3 of chain link 1, one carrier 14 to the area provided on the left-hand projection 3 and one to the area provided on the right-hand projection 3.

(27) The fitting (snap-on) is preferably done from the side, the snap-on direction is therefore especially normal to the conveying direction. The fitting (snap-on) is preferably achieved by elastic expansion or elastic spreading of preferably two narrow fastening lugs (legs) 23 provided on the carrier 14, in particular on the fastening part 15, the end of which carries a retaining bar 24 for clamping (enclosing) on the projection 3. The fitting and snap-on is carried out manually by hand, no tools are required. Likewise, carriers 14 that have already been snapped on can be dismantled again non-destructively by hand, by pushing and pulling and thus stretching the fastening lugs 23. This also enables the changing of different carriers 14 when using different materials to be conveyed.

(28) When snapped on, the two fastening lugs (legs) 23 of the carrier 14 rest resiliently with slight pressure against the flanks of the projection 3 of the chain link 1, or against the toothless protrusion 22 which forms the guide. The retaining bar 24 of the carrier 14 engages under the protrusion 22 and contacts the flank of the projection 3 exactly in the area of its toothing (latching portion) 4.

(29) The flank of the retaining bar 24 in this contact area can be designed in two different ways, either smooth (without toothing) or toothed. If it is toothed, which is not shown here, the teeth of the two parts (of the retaining bar 24 of the fastening part 15 and the projection 3) engage with each other and cause the snapped-on carrier 14 to be transversely adjustable only with greater force or not at all (depending on the spring force of the retaining bar 24 or the fastening lugs 23). If it is without teeth (smooth), as in FIGS. 1-3, the snapped-on carrier 14 is well guided and can be moved relatively easily in the transverse direction.

(30) All carriers 14 are of the same design and can be mounted in the same way selectively on either the left or right projection 3 due to their symmetrical design.

(31) Following the principles of Hygienic Design, all surfaces on the carrier 14 are designed to be as smooth as possible and without cavities (hollows). Likewise, all surfaces are beveled as far as possible so that liquids do not stop but run off.

(32) Preferably, the carriers 14 consist of two components, i.e. a soft component, here the gripping part 19, which is designed to be soft and elastically deformable and forms gripping elements in the form of extensions 16, such as thin fingers or lobes. The material to be conveyed is gently and carefully clamped with light pressure. The pressure exerted on the sometimes very sensitive material being conveyed should be as low as possible.

(33) This can be influenced and varied in a beneficial manner by the length of the fingers, their width, thickness, type, shape and form and, above all, by the softness or flexibility of the material used (preferably thermoplastics, rubber or similar with the additional properties of smooth and abrasion-resistant). Additives added during the manufacturing process can also help to achieve properties such as antistatic or antibacterial.

(34) The second component of the carrier 14 is a hard component, which holds the soft component, and both are firmly (relatively rigidly) attached to the likewise relatively rigid conveyor chain, providing sufficient support and enabling functions such as push-on or snap-on and transverse adjustment. Plastics such as POM, PA, ABS, PP or similar suitable materials are used here. Additives can help to achieve properties such as antistatic or antibacterial. The second component is realized by the fastening part 15.

(35) The two components of the carrier 14, i.e. the fastening part 15 and the gripping part 19, can either be manufactured separately and then joined (connected) together. Or both components can also be produced inseparably combined by combined manufacturing processes (e.g. by means of a 2-component injection molding process).

(36) The pressure exerted by two carriers 14 on the material clamped between them can also be significantly influenced by their position transverse to the conveying direction, as already described.

(37) FIG. 4 shows a longitudinal section, front view and top view for a chain link as shown in FIGS. 1-3. In the longitudinal section, the traction piece 11 can be seen in the head part 5. In the top view, it can be seen that the support surface 2 and the top of the two projections 3 form one plane.

(38) In FIG. 5 the two parts of the carrier 14 are clearly visible. Above in FIG. 5 the bottom view is shown from which the shape of the individual extensions 16 of the gripping part 19 can be seen. In the direction of the extensions 16, i.e. in the assembled state transversely, in particular normally, to the conveying direction 12, the gripping part 19 overlaps with the fastening part 15, where the gripping part 19 completely fills the fastening part 15, leaving of course the retaining bars 24 free. This ensures that these two parts are well connected. This can also be seen in the cross-section shown below. Here, the fastening part 15 still has ribs 27 on the inside, which are aligned parallel to the fastening lugs 23, which also serves as a connection between gripping part 19 and fastening part 15. The receptacle for the actuating part 18, designed as a pin, also penetrates the gripping part 19. In the top view of the carrier 14 in FIG. 5 below, it can be recognized that the gripping part 19 is wider than the fastening part 15 outside the fastening part 15 along the conveying direction 12. This means that the gripping parts 19, or their extensions 16, can form a continuous guide for the small parts 17 in conveying direction 12, while there is sufficient distance between the fastening parts 15 of consecutive chain links 1 to allow them to pass through bends or curves.

(39) FIG. 6 shows the side view, a cross-section normal to the conveying direction and a cross-section parallel to the conveying plane of a carrier 14 according to the invention, as shown in FIGS. 1-3 and 5. The sections in FIG. 6 also show that gripping part 19 and fastening part 15 engage with each other positively. The gripping part 19 fills the spaces between the side walls of the fastening part 15, the fastening lugs 23, and the ribs 27 of the fastening part 15, as well as the space between the ribs 27.

(40) FIG. 7 shows a perspective view of a conveyor chain on which small parts 17 are located in the form of bottle closures.

(41) FIG. 8 shows a cross-section of a chain conveyor, which is constructed from chain links 1 according to the invention. The conveying chain piece (strand) is at the top and the returning chain piece (strand) at the bottom. Chain guide profiles 20 are provided on both sides of the conveyor chain parallel to the conveying direction, on which the conveyor chain rests with its projections 3.

(42) These chain guide profiles 20 are arranged in the same way on each sideas seen in the height directionbetween the projection 3 and the bore stub 26 carrying the opening (bore) 8 for the chain pin 9, which is provided on the outside of the leg 7 of the fork part 6, and limit the position of the conveyor chain with slight play in both coordinates transverse to the conveying direction 12. The left and right chain guide profiles 20 have the same geometry and can be easily fitted or pushed onto the body (supporting frame) of the chain conveyor as required.

(43) The carriers 14 have an actuating means 18 in the form of a bolt for shifting on the upper side of their fastening part 15. Accordingly, displacement means 21 are provided on the chain conveyor, in particular displacement means that are fixed relative to the conveyor chain, i.e. links in this case. These have a groove in which the actuating means 18 are guided and are moved inwards towards the support surface 2 or outwards away from the support surface 2 according to the course of the groove. In the case shown, the carriers 14 on both sides of the conveyor chain are displaced to the same extent.

(44) The groove that guides the actuating means (the bolt) 18 is milled into a plastic profile (preferably UHMWPE), or the profile is extruded in this form in the case of series production. The plastic profile has small dimensions in cross-section, but along the conveying direction 12 it extends along the entire conveying path. In order to allow thermal expansion at such lengths different from that of the metal conveyor body, it is guided longitudinally in a metal cage 28, e.g. made of stainless steel, and has small gaps at intervals along the conveying direction 12, which allow expansion without creating stresses (deformations). The gaps are, of course, only wide enough to prevent the actuating means (the bolt) 18 from getting stuck in them. The metal cage 28 also provides better stiffness and allows larger fastening distances.

(45) The cage 28 with the guide link is now attached to adjustment elements 29 at intervals of approx. 1-2 meters towards the top. Preferably, the fastening is carried out by means of spacer elements 30, such as spacer sleeves, or otherwise height-adjustable, so that carriers 14 of different heights can be used. The spacer element 30 is fastened by means of a screw 31.

(46) In this way, the left and right cages 28 (link) are mounted on trapezoidal threaded nuts with different thread directions (1 left-hand thread, 1 right-hand thread, preferably always trapezoidal thread). These trapezoidal threaded nuts are seated on a centrally arranged trapezoidal threaded spindle 32 with a different direction of thread away from the center (one side left-hand thread, one right-hand thread), and on at least one, preferably two additional guide elements 33 in the form of e.g. a round steel bar (longitudinal axis), which prevent the trapezoidal threaded nut from rotating with the trapezoidal threaded spindle 32 and ensure good guidance and that no bending force and no moment is introduced into the links or cages 28.

(47) This can be seen better in FIG. 9. By synchronous rotation of these trapezoidal threaded spindles 32 of the adjustment elements 29, the two cages 28 attached to them can be centrally adjusted with the links.

(48) Synchronous rotation can be achieved as in the present case by toothed belt pulleys 34 (one per adjustment element 29) and a toothed belt 35 (not drawn here), or alternatively by gears and shafts, or other means for synchronous drive. It can be activated manually by a crank or motorized by a drive.

(49) As an alternative to the preferred spindle drive, eccentrics or eccentric discs or spiral discs or parallelogram guides with push rods and levers for centric adjustment could also be used to adjust the distance between the cages 28.

(50) FIG. 8 also provides an upper guide 36, which can be engaged with the small parts 17 from above the support surface 2. This upper guide 36 can be used where necessary at critical points of the conveyor line, such as in steep inclines up to the vertical or even overhanging conveyor sections (where the support surface 2 faces downwards); or in the infeed and discharge area of the chain conveyor, where closures can push each other and collide.

(51) It is important that the carriers 14, especially their stability and rigidity, are very precisely adapted to the small parts 17 to be transported and their weight and size, in order to prevent the small parts from slipping through unintentionally.

(52) To reduce contamination and infection with germs of the small parts 17 on the conveyor chain, the conveyor chain is surrounded by an enclosure 25. This here is constructed in two parts, wherein each part can be opened and closed by pivoting. The enclosure 25 may be transparent, for example made of polycarbonate, so that the processes inside the enclosure can be observed.

(53) FIG. 10 shows a perspective view of a possible chain conveyor surrounded by an enclosure 25. Four straight conveyor sections are provided here, each of which merges into the other by a 90 deflection, wherein the deflections are either made by the chain guide profiles 20 themselves or by rotatable guide discs (curved discs) or deflection discs, as can be seen from the corresponding shape of the enclosure at the bottom right-hand corner during the first deflection.

(54) FIGS. 11-13 show the same chain link 1 in each case, in particular with the same projections 3, although the carriers 14 are designed differently in each figure. The carrier 14 in FIG. 11 has the lowest height, the gripping part 19 and the fastening part 15 are at the same height at the top, but are slightly less high than the small part (bottle closure) 17. The carrier 14 in FIG. 12 is higher than that in FIG. 11, the gripping part 19 and the fastening part 15 are at the same height at the top again, the small part (bottle closure) 17 protrudes over the carrier 14. The carrier 14 in FIG. 13 has the greatest height, accordingly the gripping part 19 and the fastening part 15 are also designed higher, wherein here too the small part (bottle closure) 17 protrudes beyond the carrier 14.

(55) FIG. 14 shows a chain link in which the carriers 14 are pretensioned with spring elements 37, i.e. are pulled towards each other by the spring elements 37. One spring element 37 is provided per carrier 14. The spring element 37 is surrounded by the carrier 14 and the chain link 1, more precisely its projection 3. Here the spring element 37 is arranged in a recess on the underside of the carrier 14. Here the spring element 37 is supported outwards by a projection of chain link 1 or its projection 3. The spring element 37 is designed as a cylindrical spring. The carriers are shown here in the maximum open position. This can be achieved if the carriers are pushed outwards by means of their actuating means 18 by displacement means 21, such as links.

(56) The gripping part 18 of the carrier 14 has four thin extensions 16 and is particularly suitable for sensitive small parts 17. A groove 38 is provided in the middle of the support surface 2 in the conveying direction. So here, chain-link 1 at its upper side will show a central arranged depression, a wide groove 38. This serves to improve the transfer into a closure groove following the direction of conveyance according to the invention or into another conveying element or into another device at the end of the conveying line. The conveyor chain consisting of the chain links 1 runs e.g. over a deflection wheel (this can also be the drive wheel), and a removal wedge or a removal blade engages in this groove 38 in the conveying direction, so that the material to be conveyed, i.e. small parts such as a closure, does not follow the curve of the conveyor chain, but is pushed straight on over the removal wedge or the removal blade.

(57) The feeding of small parts 17 onto the chain links L at the beginning of the conveyor line can also be carried out by means of groove 38 and with an appropriate feeding wedge or feeding blade. However, the task can also be performed by means of a gravity chute, e.g. diagonally from above.

(58) Otherwise the chain link 1 and the carriers 14 in FIG. 14 are designed in the same way as in FIGS. 1 to 13. However, a toothing 4 at the projection 3, as in FIGS. 1-3, is then not necessary. If there is a toothing 4 on the projection 3, spring elements 37 could still be used if the carrier 14 has no toothing and can therefore slide on the projection 3.

(59) FIG. 15 shows the chain link from FIG. 14, wherein the carriers 14 are shown here in the closed position. This means that the spring elements 37 are in a relaxed, non-compressed state. The distance between the two carriers 14 is the minimum possible here.

(60) In FIG. 16 the chain link from FIG. 14 or 15 is shown in a possible holding position where a small part 17 is located between the carriers 14. The small part 17 slightly compresses the spring elements 37 which keep the small part 17 in its position.

(61) FIGS. 17 to 22 show different embodiments of gripping parts. The gripping part 19 in FIG. 17 has here exactly one extension 16 made of elastic material for holding small parts 17, wherein the extension 16 touches the small part 17 with a flat boundary surface. The cross-section of the only extension 16 deviates slightly from the rectangular shape here, the cross-section is trapezoidally extended towards the other carrier 14. The dimension of the extension 16 in conveying direction 12 is larger than that of the fastening part 15. This gripping part 19 is suitable for robust small parts 17, is particularly hygienic and easy to use and to manufacture.

(62) In FIG. 18, the gripping part 19 has an approximately trapezoidal cross-section with a curve on the long side that is oriented towards the small part 17. The gripping part 19 thus forms a curved extension 16 made of elastic material and can at least partially enclose the small part 17 with its curvature. The curvature of the gripping part 19 is considerably less than that of the small part 17. The gripping part 19 in FIG. 21 is similar to FIG. 18, but is less long in conveying direction 12.

(63) The gripping part 19 of FIG. 19 has four circular arc-shaped extensions 16, wherein the curvature of the circular arcs is directed outwards, towards the small part 17, and the circular arcs are aligned on a straight line. Of course, more or less than four circular arc-shaped extensions 16 could be used. FIGS. 20 and 22 have five and three pointed extensions 16 respectively, which are also formed by four and two arcs respectively, the curvature of which is directed inwards. The circular arcs are again aligned on a straight line, the tips of the extensions 16 are thus disposed on a straight line.

(64) The gripping parts 19 of FIGS. 19, 20 and 22 have a better grip than the gripping parts of FIGS. 17, 18 and 21 with a greater softness of the extensions 16.

(65) It would also be conceivable to attach two carriers with different gripping part 19 to each chain link 1 of a conveyor chain. For example, seen in conveying direction 12, on the left-hand side smooth gripping parts 19 (only one extension, see carrier in FIG. 17), and on the right-hand side with fingered extensions 16 (several extensions, see e.g. FIGS. 14-16 or FIGS. 1-3). Any other left/right combinations are also possible.

(66) However, preferably for all chain links 1 of a conveyor chain, all gripping parts 19 or extensions 16 should be identical on the left and also on the right.

LIST OF REFERENCE NUMERALS

(67) 1 Chain link 2 Support surface 3 Projection (means for fitting a carrier 14) 4 Toothing 5 Head part 6 Fork part 7 Leg 8 Bore (opening) 9 Chain pin 10 Cavity in head part 5 11 Traction piece 12 Conveying direction 13 Elongated hole (opening) 14 Carrier 15 Fastening part 16 Extensions of the gripping part 19 17 Small part 18 Actuating means (bolt) on the fastening part 15 19 Gripping part 20 Chain guide profile 21 Displacement means (link) 22 Protrusion at the projection 3 23 Fastening lugs 24 Retaining bar of the fastening part 15 25 Enclosure 26 Bore stub 27 Ribs in the fastening part 15 28 Cage for the displacement means (link) 21 29 Adjustment element for the displacement means (link) 21 30 Spacer element 31 Screw 32 Trapezoidal thread spindle 33 Guide element 34 Toothed belt pulleys 35 Toothed belt 36 Upper guide 37 Spring element 38 Groove