GB2363445A

GB2363445A - Flat chain joint

Info

Publication number: GB2363445A
Application number: GB0112200A
Authority: GB
Inventors: Reinold Krohm
Original assignee: ADAM UDO MASCHINENFABRIK; Udo Adam Maschinenfabrik
Current assignee: ADAM UDO MASCHINENFABRIK; Udo Adam Maschinenfabrik
Priority date: 1998-11-20
Filing date: 1999-11-22
Publication date: 2001-12-19
Also published as: WO2000031438A3; WO2000031438A2; AU3030200A; DE19901233A1; GB0112200D0

Abstract

Link chains for flat chain joints (1) used in underground mining operations need to be joined to each other for use with extraction machines and conveyors. The inventive flat chain joints consist of two U-shaped half-locks (2, 3) and a locking element (4) arranged between the inner and outer limbs (6, 7, 8, 9). The inner and outer limbs (6, 7, 8, 9) are provided with retaining teeth (10, 11, 12), whereby the lock joint (5) is substantially closed in order to create additional retaining teeth (44, 45) in the region of the centrepiece (18) on two opposite-facing sides (15, 16) of the inner limb (7, 9). Said additional retaining teeth (44, 45) in the region of the centrepiece (18) reduce the amount of stress exerted upon the other pairs of retaining teeth and prevent or substantially reduce concentrated amounts of stress from arising in the base of the root.

Description

2363445 Flat chain joint

Description

The invention relates to a chain joint for round-iink chains, in particular for round-link chains used in underground mining and tunnelling, comprising two U-shaped lock halves and a bolting element (4) which can be inserted into the lock joint between the lock halves equipped alternately on the outer limbs and inner limbs with retaining teeth in the closed state.

A chain joint or lock of this type is known from DE-GM 81 25 894 but also DE-PS 34 44 008 and DE-GM 93 14 756. With these known locks, the two lock halves are locked together once the retaining teeth are intermeshing, by the inserted bolting element, so they cannot slip or fall apart unintentionally. Adequate protection against kinking is to be ensured, for example, by a specially designed bolting element which, after insertion, is pressed apart by springs or other blocking parts in such a way that these surfaces press against the rounded regions of the inserted and mutually connected chain links. In particular in rough underground mining operations, however, problems can arise with these spring-loaded bolting elements, particularly if the spring-loaded parts are damaged in any way. According to DE-GM 93 14 756, three respective pairs of retaining teeth are provided for reliably transmitting the necessary forces. In addition, the lock parts are superficially strengthened by plastic deformation in the transition region so that they are better able to transmit or hold the forces occurring. This is due to the high forces which occur during underground use, particularly in extraction machinery, and which also act on the pairs of retaining teeth.

It is accordingly the object of the invention to create a chain joint which reduces stress on the pairs of retaining teeth and reduces concentrations of stress in the base of the root. The object is achieved according to the invention in that the lock joint is substantially closed and in that the two mutually opposed sides of the inner limb of the lock halves are designed to intermesh in the manner of teeth in the region of the bolting element designed as a centrepiece and to enclose the centrepiece. Corresponding additional teeth in the region of the centrepiece enable this region also to be fully involved in the transmission of the pulling force. Stress on the other retaining teeth acting between the joint halves is therefore reduced. Furthermore, a harmful concentration of stress in the base of the root of the two inner limbs is reduced by the counter effect of the bending moments. Moreover, assembly and disassembly is not complicated by these additional retaining teeth but is ultimately simplified, as will be described in more detail hereinafter.

According to an expedient embodiment of the invention, the lock joint between the two lock halves extends obliquely and diagonally through the centre of the halves and therefore also of the centrepiece and therefore acts tangentially on the semicircular chain eyelet of each lock half. Additional teeth are therefore created which act in the region of the centrepiece and are similarly designed and act in the manner of a hook so that they can advantageously participate fully transmission of pulling force. It has already been above that, in particular, harmful concentrations of the base of the root are thus avoided. Rather, this in the mentioned stress in region is advantageously incorporated in the overall operation of the chain joint.

According to a further development of the present invention, recesses are provided alternately to the lock joint. These recesses are arranged on both sides of the centrepiece and simplify assembly, expediently being arranged pointsymmetrically to one another and then allowing immersion of the hook tooth of the adjacent inner limb after the centrepiece has been driven out, thus making it easier to take apart the chain j oint.

Assembly and disassembly are simplified, in particular, if the height of the recesses is adjusted to correspond substantially to the depth of the retaining teeth. The lock halves are simply pushed apart altogether accordingly so they can then be taken apart.

The centrepiece which serves to fix the two lock halves can have different shapes, the simplest shape being that of a corresponding bolt. The invention also proposes that the centrepiece has the form of a rectangular rod. Both designs allow simple insertion and fixing inside the chain lock and also corresponding assembly, the recesses additionally simplifying assembly, as mentioned.

In a further embodiment, the centrepiece is designed as a Zshaped component and the lock joint is adapted thereto, the core extending orthogonally to the lock joint. With a design of this type, a root height of the inner limb can be increased in comparison with other embodiments, several possible methods of securing the centrepiece being permitted, some of which will be described in more detail hereinafter.

Finally, the invention also proposes that the centrepiece has the form of a stepped block, and this allows a further increase in the overall tooth thickness.

To secure the centrepiece, it is expedient to use an embodiment in which the centrepiece is in the form of two stop bushes of which the flanges have a hexagonal shape and in whose central bore a cylinder head screw and an opposing hexagon nut can be inserted. The two stop bushes can be inserted relatively easily and have a central bore through which the cylinder he-ad screw can easily be twisted such that it is secured itself and simultaneously fixes the two parts of the centrepiece relative to one another to reliably prevent the chain joint from falling apart.

A further possibility involves using a single-stop bush in combination with a cap nut rather than the two stop bushes, a cylinder head screw again being inserted via the central bore in such a way that it f ixes the centrepiece with the aid of the cap nut. The screw connection is so arranged that it is not stressed by the forces occurring and disassembly is still possible after prolonged use.

A further design of the centrepiece proposes that the centrepiece has the form of two conical bushes with a central bore into which a cylinder head screw or hexagon nut can be inserted. These conical bushes have the advantage that, when fixed via the cylinder head screw, they simultaneously also have an enclosing effect which promotes the fixing of the centrepiece in the chain joint. The cylinder head screw which ultimately merely f ixes the conical bushes prevents release of the centrepiece as the two conical bushes can be driven apart by suitable tools once the cylinder head screw has been unscrewed, so the chain joint is opened.

Finally, it is possible to use a centrepiece in the form of a stepped block and collar plates with central bore into which a countersunk rivet can be inserted. The countersunk rivet can also be used with the conical bushes or centrepieces of different designs, the described, embodiment with the stepped block affording the advantage of also producing a desirable total tooth thickness.

Owing to the particular design of the inner limb of the two lock halves and also of the centrepiece, this region is also incorporated in the transmission of the pulling force, the additional retaining teeth formed in the region of the centrepiece having an average thickness of 16 to 18 mm according to an expedient development of the invention. Corresponding shaping of the additional retaining teeth in the region of the centrepiece ultimately ensures that this region can be fully included in the transmission of force and also performs this function fully so that substantially more uniform loading of the chain joint can be achieved overall.

The back of the outer limb in the region of the two front teeth can advantageously be higher in design and the bending crosssection therefore greater if, according to the invention, the crest part of the retaining teeth of the inner limbs is designed to have the same slope as the lock joint. However, the teeth have the same height and enable the chain joint to be taken apart and put together easily if the centrepiece is appropriately handled.

The outer limb back and the tooth hook of the inner limb can be further reinforced if the retaining teeth of the inner and outer limbs are shaped so as to form saw teeth. This may possibly also result in advantages with respect to production and assembly, particularly as the teeth can be kept and designed substantially identical. Reliable transmission of the forces is also achieved hereby, ultimately regardless of the shape of the centrepiece.

Owing to the jointly carrying centrepiece, the number of teeth in each pair of retaining teeth can be reduced from three to two, resulting in a total tooth thickness of 30 mm per limb. It is advantageous according to the invention if the inner limbs are designed to rest on one another with their locking faces with an angle of deviation of about 24.4' obliquely to the pulling direction so as to close the lock joint. The hook-shaped tooth therefore clasps the round or angular centrepiece for a further 6 mm, and the total tooth thickness increases, for example, by 13 mm or even 48 mm. The outer limb can also be shorter in design so the shearing force acting on the centrepiece is reduced by about 9% owing to the oblique plane. The root cross-section of the inner limb becomes considerably thicker.

With a further reduction in the number of teeth, the invention proposes that each pair of retaining teeth has a retaining tooth in addition to the jointly carrying centrepiece. The number of teeth can therefore be reduced from three to one so the outer limb can be even shorter and, in particular, the error rate in the carrying content can be considerably reduced. To prevent outward bending owing to possible parting forces, it is proposed that the outer limb is designed so as to engage beneath the inner limb with a nose.

It has already been mentioned hereinbefore that an embodiment of the centrepiece is a Z-shaped component and it is additionally proposed that the core of the Z-shaped component has the form of a rhombus or parallelogram, the lateral faces extending at right angles to the right axis and the crest faces parallel to the lock joint. The foot thickness of the retaining tooth therefore increases considerably, and this is in turn a great advantage for the transmission of force which is made more uniform overall. The back of the additional retaining tooth created in the region of the centrepiece extends at right angles to the lock joint. The respective U-arc of the chain link to be connected is therefore located securely within the chain eyelet without any negative frictional forces occurring. Rather, there is more or less linear contact which advantageously reduces wear.

Assembly of the U-shaped lock halves which is freer from jamming is achieved in that the alternate point- symmetrical recesses are provided. A nose-shaped projection which engages in a corresponding recess in the inner limb and is arranged and provided on the outer limb is provided at the end of the outer limb to prevent transverse displacement.

To increase protection from kinking, the chain fronts are provided with a respective anti-kink nose.

The corresponding anti-kink noses are so designed that the chain joint can only move to a limited extent in the adjoining chain links. Additional retaining teeth are also provided here, and are assisted, for example, by a Z-shaped centrepiece. Kink protection can thus be increased without a particular design of the centrepiece, more specifically in a region where no protection against kinking is provided in the state of the art. The corresponding anti-kink noses may be provided during production of the chain joint or the lock halves to avoid substantial additional expenditure.

High protection from kinking is achieved, in particular, if the anti-kink nose is designed to produce a kink-free pivot zone of about 40% and preferably extends over 45 mm for this purpose. This means that only a relatively small region on either side of the centre line is provided with an anti-kink zone rather than the entire chain front. An effective anti-kink means is therefore created in the main pulling direction, and a collar in the eyelet region of the chain joint can advantageously be dispensed with. An overall reduction in kinking of 28% in the arc region of about 140' is thus achieved.

Owing to the protection from kinking ensured in this way, it is advantageously possible to reduce the tooth thickness from 30 to 22 nun with a design with single-tooth pairs of retaining teeth. The outer limb is then about 15 mm shorter, producing a very robust chain joint overall.

A desirable force-transmitting central part is one which is parallelogramlike in cross-section. With this form of centrepiece, which is fixed by a groove nut or the like as usual, the corresponding additional retaining teeth can take up and convey the necessary forces exactly in the longitudinal direction. The anti-kink noses are also provided on both sides with this solution. A single-tooth pair of retaining teeth can therefore be embodied in an advantageous manner.

In addition to the anti-kink noses, the inner limbs can be equipped with catch humps and the outer limbs wi th correspondingly designed catch grooves in an expedient development, the centrepiece having a long supporting base or also being designed differently and being screwed to groove nuts, as known. A design with pairs of single, double and trebleretaining teeth can be achieved with this embodiment.

As already mentioned, the centrepiece may be the parallelogramlike or Zshaped centrepiece or even a centrepiece which has a long supporting base and where fixing is achieved with a central screw or shrink connection without substantial tools being required for this purpose. The long supporting base also has the advantage that it can be so designed and extended that the pivot region of the adjoining chain links can be correspondingly restricted therewith. The centrepiece extends obliquely and correspondingly parallel to the lock joint and also to the retaining teeth. It may be expedient to adapt the chain eyelet further to the shape of the adjoining chain link, and this can be achieved in that the retaining tooth of the inner linib close to the eyelet is reinforced and arcuate in design. The corresponding centrepiece with the long supporting base and, for example, the shrink connection allows rapid and precise completion and assembly of the chain joint.

Different variants of chain joints can be embodied with a centrepiece of this design having a long supporting base. The saw tooth-shaped retaining teeth and the central part have the same or a different inclination. For example, saw teeth and centrepiece and teeth can be inclined at 16' or at 12', the thickness of the tooth foot of the tooth close to the eyelet being 4 mm thicker at 16 mm. If teeth and central part are inclined at 12' and a correspondingly thinned centrepiece used, an inner limb hub which has a uniform thickness of 24 mm and is, for example, about 4 mm thicker is achieved.

It is also conceivable to deviate from the inclination of the central part, the lock joint extending parallel so the centrepiece is also enclosed by the mutually opposed sides of the inner and outer limbs in this case. The centrepiece and saw tooth-shaped retaining teeth are designed to extend horizontally in the pulling direction, and it is particularly advantageous if the centrepiece is provided, on both sides, with saw teeth which are designed to carry jointly and engage in the inner limbs. This particular design of the centrepiece also produces the clear additional teeth again in the region of the centrepiece and therefore the advantageously uniform transmission of the forces occurring.

With respect to the design of the retaining teeth, assembly is straightforward if the retaining teeth have no undercuts. For transmitting the forces, however, it may be advantageous if the retaining teeth have undercut teeth, and this can, for example, also be advantageously embodied in a double-tooth pair of retaining teeth. Anti- kink noses are provided on the chain fronts and an additional catch is also provided at the ends of the inner and outer limbs. This undercut of the retaining teeth creates an advantageous claw-like connection which has a pulling in effect and counteracts any bending. The saw tooth shape also provides additional advantages overall in comparison with conventional block teeth in so far as a thicker tooth shape with a substantially thicker tooth foot can be achieved. These retaining teeth can be produced with profile milling cutters to simplify production. Assembly of the chain joint is ultimately also simplified by the shape of the saw tooth which is conical in crosssection.

The described design, whether with undercut teeth or without such teeth, can also be improved with regard to freedom from kinking in that the outer retaining teeth have an oblique spring and groove catch extending parallel to the inclination of the teeth. This restricts the freedom of movement of the coupled chain links to the main functions predetermined by conveyor or plough operation, so the reliability of operation is increased and the use of anti-kink ribs, which is ineffective anyhow owing to the zip fastener effect can be avoided.

A further method of stabilising these chain joints in the end region of the limbs is achieved according to the invention in that the outer retaining teeth are designed to produce a forked catch. The long outer limbs are therefore advantageously and additionally secured against transverse displacement at their ends.

The forked catches according to the present invention secured by a shearing bolt prevent the forked catch from bending. This shearing bolt is normally hardly loaded as the respective double-toothed pair of retaining teeth connecting the inner and outer limbs with a tooth foot plane preferably inclined at 4' is equipped with so-called saw teeth.

With a double-toothed pair of retaining teeth, it is advantageous to use a horizontal centrepiece again which is secured by groove nuts and in which the kink noses are provided at the chain fronts. The forked catch with the shearing bolts allows reinforced outer limbs at the front transition. It is advantageous for this purpose if the anti-kink noses are designed to produce an enlarged anti-kink zone and adhere to a lock thickness of c = 41.

Kink protection is further optimised by a development in which the centrepiece is designed to have an anti-kink collar in the eyelet region. This collar guides the respective adjoining chain link in the chain joint in such a way that the movement of the adjoining chain link is exactly predetermined and restricted in each case.

Assembly is simplified, in particular, by a design in which the centrepiece is designed in two parts with a long supporting base and is secured by one or two through-bolts. The through-bolts are two cylinder bolts with a square nut. Other connecting units are also conceivable.

With a further method of securing the outer and inner limbs, a so-called securing nose is provided at the end of the outer limb and the inner limb of each lock half, the securing nose being arranged and designed to engage in a fork-shaped recess of the front attachment of the respectively adjacent lock half. Advantageous protection from transverse displacement and, at the same time, an anti-kink device are achieved in this way. These securing noses are located in the eyelet region, preferably in addition to the securing systems provided at the exterior of the limb ends.

Various methods of taking up parting forces but also for optimum transmission of the main pulling force by particular design of the centrepiece and the associated ends of the limbs have been mentioned hereinbefore. This is further optimised in that the long limbs of the Zshaped component are shaped so as to be convexly curved at the end in a plan view and, together with a furrow associated with the inner limb, to form a channel into which an arcuate securing element can be driven. An advantageous interlocking connection not only of the securing elements but, in particular, also of the centrepiece designed as a stepped block is thus achieved without a substantial loss of crosssection on the inner limbs, so a loss of the centrepiece, which would endanger reliability of operation which occurs, for example during the passage of the conveyor chain belt under the impact roller of a continuous crusher rotating at high speed and therefore reducing rock and coal or during the restoration and oscillation of the resiliently pulsating conveyor chain and also with the plough chain subjected to jerky stress and vigorous impacts and, not least, under the heap at the transfer station during the passage over the sprocket wheels rotating in the crush and dragging hard pieces of rock into the pockets, and causes considerable complications is avoided.

In order to round off the anti-kink protection, it is proposed that the ends of the inner limbs, in particular when designed as a double-hook tooth, are designed to limit the chain eyelet of the adjacent lock half substantially circularly via an anti-kink collar. This produces a concave envelope curve shape which prevents kinking or immersion of the chain link coupled in the chain joint into the clear internal spaces of the chain eyelet and therefore prevents premature destruction of the lock as the anti-kink collars are not located in the wearing region of the chain joint but are located without contact in the shade of the chain and are not exposed to wear under tension. Contact with the chain link only in the case of a build-up of chain with resultant slack chain with an angle of deviation of 67' in the chain hinge is no problem, the force only being produced by negligible dead weight components in slack chain.

The anti-kink collar is expediently formed by a concave envelope curve which therefore forms two blocking embankments. The adjoining chain link is therefore secured optimally in the chain joint. In a further variation, the effect of the blocking embankments is further increased in that the hingeability of the chain eyelet is restricted from 67' to 40', more specifically by a sickle-shaped front thickening of the chain joint, associated with the furrow width of the sprocket wheel, so the use of sixtoothed sprocket wheels, which are operated as the smallest size in the category of these robust mining chains, is ensured. For this purpose, the chain fronts have, in particular, a sickleshaped front thickening. The risk of kinking is further restricted and the strength in the respective joint region of the chain lock is further increased in the form of an addition for wear. According to a further variation, the front thickening can even be shaped to a profiled anti-kink nose with the operating details mentioned there.

It is advantageous, in particular with a single-tooth pair of retaining teeth if the retaining tooth of the outer limb has a central groove extending continuously in the longitudinal direction of the lock, and the associated tooth gap of the inner limb has a correspondingly shaped tongue. Transverse and rotational forces can therefore be reliably controlled. This tongue and groove design is advantageously protected between the respectively paired outer and inner limbs in that the tooth of the outer limb has a groove extending in the longitudinal direction of the chain joint in the centre of its width. The corresponding tongue is able to engage in this groove.

According to a development, it is proposed that the tongue is connected interchangeably to the inner limb so that, for the first time for ineffective concave/convex centring, extremely strong interlocking of the two lock halves against transverse forces is created, of the type required, in particular, in crusher conveyors where the toothed chain joints are blasted, in particular in a horizontal position, by the impact of the crusher rollers which are loaded with high kinetic energy and cause cost-intensive interruptions in operation. A further advantage is that a tooth thickness of the single-tooth pair of retaining teeth can be substantially enlarged owing to the omission of the nose/forked catch and an extremely robust character is achieved owing to the tooth thickness and the connection to the short penetrated outer limb.

Fixing, in particular permanent fixing, of the centrepiece is achieved, in particular, in that the, for example, Z-shaped centrepiece is designed as a stepped block and a securing element with a correspondingly shaped attachment can be driven between it and the inner limb having a central groove, the ends of the securing element being designed to bend down in the direction of the stepped block. The securing member clasps the stepped block in a lock- tight flush manner, the constriction of the limbs being easy to disassemble as space for application of a chisel or other blasting tool is provided at the bent ends of the securing element.

Finally, assembly can also be simplified in that the securing element has a finished head shape on one side, is slit in the manner of a split pin on the opposite side and has limbs which can be bent down in both directions. The two securing elements can therefore advantageously be introduced after insertion of the centrepiece into the lock joint in that the securing element shaped as a rod with a square cross-section, with a finished head shape at one end, is bent back at the other end at its limbs which are slit in the manner of a split pin to achieve the head shape as on the opposite side. The bent limbs are introduced and protected in recesses in the lock halves and the centrepiece, any blind processes during assembly, of the type involved in almost all toothed locks in the form of invisible catch springs, snap rings, spring hollow cylinders and spheres in snap and bayonet fittings are avoided and the associated imponderables can no longer arise. An interlocking securing connection which can be inspected and monitored at any time is therefore created, which is also easy to assemble and disassemble owing to the identical spread head shape of the securing element.

Finally, securing of the centrepiece by wedges is also possible, the invention proposing that the centrepiece is fixed via two opposing transverse wedges which preferably have a taper of tg 1:25 to tg 1:100. The centrepiece is therefore secured by friction by the two opposing transverse parts which produce an effective gripping connection, assuming and providing that they rarely have to be released and tightened again.

The invention is distinguished, in particular, in that hookshaped teeth which surround the centrepiece and contribute to the transmission of pulling force are created in the region of the centrepiece on the respective inner limbs. The other retaining teeth between the inner and outer limbs are therefore relieved of stress. A particular advantage is that harmful concentrations of stress in the base of the root of the two inner limbs can be reduced. In addition, the outer limb can be shortened and the entire chain joint can therefore be constructed more stably, depending on the construction. Owing to its particular construction, the centrepiece is fixed between the two limbs of the U-shaped lock halves in such a way that it is also able to withstand rough operation and also allows reliable disassembly even after prolonged service lives. The shape of the centrepiece can be adapted to the respective applications, but it is important to provide appropriate screw connections which always allow the respective centrepieces to be released in a planar manner and without great effort so that the locks can be disassembled or also assembled.

Further details and advantages of the subject of the invention will emerge from the following description of the associated drawings which show a preferred embodiment with the necessary details and individual parts.

Fig. 1 is an enlarged view of a flat chain joint in a longitudinalsection, Fig. 2 is a reduced reproduction of the flat chain joint of the same design, Fig. 3 shows the flat chain joint according to Fig. 2 in a cross-section, Fig. 4 shows a flat chain joint in a design with modified retaining teeth, Fig. 5 is a cross-section through the flat chain joint according to Fig. 4, Fig. 6 shows a flat chain joint with saw teeth in a longitudinal section, Fig. 7 shows the flat chain joint according to Fig. 6 in a cross-section, Fig. 8 shows a flat chain joint with a reduced number of teeth, Fig. 9 shows a flat chain joint with stepped block as centrepiece, Fig. 10 is a cross-section through the flat chain joint according to Fig. 9, Fig. 11 shows a flat chain joint with further reduced number of teeth in a longitudinal section, Fig. 12 shows a flat chain joint simpler than the embodiment in Fig. 11, Fig. 13 shows a flat chain joint with emphasised recesses on either side of the centrepiece, Fig. 14 shows a flat chain joint with recesses on either side but corresponding filling parts which are applied to the centrepiece, Fig. 15 shows a flat chain joint with a Z-shaped centrepiece with a square core extending orthogonally to the lock joint, Fig. 16 shows a flat chain joint with a Z-shaped centrepiece in whi ch the centrepiece is in the form of a rhombus or parallelogram, Fig. 17 shows a chain joint with single-tooth pair of retaining teeth and anti-kink noses, Fig. 18 is a longitudinal section through the chain joint according to Fig. 17, Fig. 19 shows the chain joint according to Fig. 17 with reduced outer limb, Fig. 20 shows the chain joint with a parallelogram-like centrepiece, Fig. 21 is a cross-section through the chain joint according to Fig. 20, Fig. 22 shows the chain joint with multiple pairs of retaining teeth with anti-kink noses, Fig. 23 is a cross-section through the chain joint according to Fig. 22, Fig. 24 shows a chain joint with pairs of multiple retaining teeth with extended supporting base for the central part, Fig. 25 is a cross-section of the chain joint according to Fig. 24 with groove nut caulked on both sides, Fig. 26 is a cross-section according to Fig. 25 but with the groove nut caulked on one side, Fig. 27 shows the chain joint with saw teeth and extended central part, inclined at 16', Fig. 28 shows the chain joint according to Fig. 27, but inclined at 12', Fig. 29 shows the chain joint according to Fig. 27 with thickened central part, Fig. 30 shows the chain joint according to Fig. 27 with enlarged tooth shear thickness and horizontally extending central part, Fig. 31 shows the chain joint according to Fig. 30 but the central part equipped with saw teeth, Fig. 32 shows the chain joint wi th double-tooth pair of retaining teeth and tongue and groove catching with undercut tooth foot, Fig. 33 shows the chain joint according to Fig. 32 with reduced undercut of the tooth foot, Fig. 34 shows the chain joint according to Fig. 32 without undercut tooth foot, Fig. 35 is a cross-section through the chain joint according to Fig. 34, Fig. 36 is a cross-section of a lock thickness of 41 mm or 46 mm, Fig. 37 shows further cross-sections of the chain joint in the front region, Fig. 38 shows the chain joint according to Fig. 32 without undercut tooth foot, Fig. 39 shows the chain joint with forked catch, Fig. 40 shows the chain joint according to Fig. 39 with two-part centrepiece, Fig. 41 is a longitudinal section through the chain joint according to Fig. 40 with a throughbolt, Fig. 42 is a longitudinal section through the chain joint according to Fig. 40 with two through-bolts, Fig. 43 is a cross-section of the chain joint according to Fig. 40 with shearing bolt, Fig. 44 shows the chain joint with single-tooth pair of retaining teeth with supplementary method of securing, Fig. 45 is a section through the chain joint according to Fig. 44 with stepped block and inserted securing piece, Fig. 46 is a section through the chain piece with adjoining chain links and anti-kink collar, Fig. 47 shows the chain joint according to Fig. 44 but with additional front thickening, Fig. 48 is a section through the chain joint according to Fig. 47, Fig. 49 is a section through the chain joint according to Fig. 47 with interlocking stepped block as centrepiece, Fig. 50 is a detail of a longitudinal section of the chain joint according to Fig. 44 with anti-kink collar and anti-kink nose, Fig. 51 shows the chain joint with modified securing method, Fig. 52 is a cross-section through the chain joint according to Fig. 51, Fig. 53 is a section through the chain joint according to Fig. 51, Fig. 54 shows a further method of securing the stepped block supplementary to the illustration in Fig. 53 and Fig. 55 shows the wedge securing means for the centrepiece, in a cross- section.

Fig. 1 shows a flat chain joint 1 corresponding completely to the one shown in Fig. 2. This flat chain joint 1 consists of two lock halves 2, 3 which are secured and clamped relative to one another by an interposed bolting element 4. In contrast to known flat chain joints, a lock joint 5 is provided here which extends centrally through the bolting element 4 in such a way that additional teeth are formed or created in the region of the bolting element (4) in addition to the retaining teeth 10, 11, 12 formed between the outer limbs 6, 8 and the inner limbs 7, 9.

Fig. 1 shows that each two pairs of retaining teeth are embodied with three respective retaining teeth 10, 11, 12 per inner and outer limb 6, 7, 8, 9. The total tooth thickness per limb is considerable, as can be seen clearly in Fig. 1. The retaining teeth 10, 11, 12 are formed on the respectively opposed sides 15, 16 of inner limb and outer limb 6, 7, 8, 9.

The bolting element 4 formed as centrepiece 18 is clearly clasped by the two inner limbs 7, 9 of the two lock halves 2, 3 and is involved in the transmission of pulling force. This design advantageously produces the above-mentioned additional tooth with an average thickness of about 20 mm for each inner limb 7, 9. This not only increases the total tooth thickness but also relieves stress and considerably reduces harmful concentrations of stress owing to the counter effect of this additionally created tooth 52.

Like Fig. 2, Fig. 1 shows that the chain eyelets 19, 20 arranged on both sides of the centrepiece 18 as normal are substantially closed by the particular construction of the additional retaining tooth 52, recesses 22, 23 remaining on either side of the centrepiece 18, at least in this en-Lbodiment, to simplify disassembly.

Fig. 3 shows that the centrepiece is in the form of two stop bushes 30, 31 of which the flanges 32 have a hexagonal shape to assist fixing in the inner limbs 7, 9 and to prevent rotation. The stop bushes 30, 31 and the flanges 32 have a central bore 33 into which a hexagon nut 34 is inserted so that the cylinder head screw 35 also inserted can be suitably enclosed and encloses the two stop bushes 30, 31.

In contrast to the variation shown in Fig. 1 and 2, the head part 47 of the inner limb teeth 10, 11, 12 falls away backward with the same tooth height at the same slope of 24.4' as the closing faces of the chain eyelets 19, 20 in the embodiment shown in Fig. 4 and Fig. 5, so that the back of the outer limb 6, 8 is higher in the region of the two front teeth and the bending cross-section is therefore reinforced.

The centrepiece 18 here has the form of a stop bush 30 with a cap nut 36 into which the cylinder head screw 35 can be screwed in order to effectively fix the entire centrepiece 18 in the flat chain joint 1.

Fig. 6 shows a further variation embodying a saw tooth 48 by means of which the back of the outer limb 6, 8 is further reinforced. The tooth hook of the inner limb 7, 9 is also reinforced.

Fig. 7 is a cross-section through the design according to Fig. 6 illustrating that the centrepiece 18 here has the form of two conical bushes 38, 39, which are connected to one another via the cylinder head screw with the inserted hexagon nut 34 in such a way that they are fixed inside the flat chain joint 1 and therefore ensure that the parts of the flat chain joint 1 are rigidly connected.

Owing to the jointly carrying centrepiece 18, the number of teeth is reduced from three to two in Fig. 8. The closing face 49, 50 of the two inner limbs 7, 9 lie at an angle of deviation of 24.4' obliquely to the pulling direction, so the hook-shaped retaining tooth 52 of the retaining tooth pair 51 can clasp the centrepiece 18, which is shown as round here, even further than in the embodiments described hereinbefore so that the total tooth thickness increases by 13 mm, for example to 48 mm. Furthermore, the outer limb 6, 8 can advantageously be shorter and the shearing force acting on the centrepiece 18 can be reduced. The root cross-section of the inner limb 7, 9 becomes considerably thicker. Fig. 8 shows particularly clearly that the lock joint 5 extends almost continuously here and touches the two chain eyelets 19, 20 tangentially. Kink preventers can be omitted here because the chain links to be connected are securely mounted in the flat chain joint 1. The additionally created teeth are designated by 44, 45 as additional retaining teeth.

The design according to Fig. 9 is similar in principle but is provided with greater recesses 22, 23.

Fig. 9 also shows a particular embodiment in so far as a stepped block 28 is used as jointly carrying element. The connecting part or fixing part for the centrepiece 18 extends centrally through the core 27. A collar plate 44 in which the countersunk rivet 41 can be fixed is provided in the stepped block 28 shown here. Securing can be achieved just as well by a screw connection, or the riveting can be achieved using a different shape of centrepiece 18.

Fig. 10 shows a corresponding embodiment with the collar plates 40 and the countersunk rivet 41 in which the centrepiece 18 is also shown in cross-section.

The jointly carrying centrepiece 18 enables the number of teeth to be further reduced, Fig. 11 showing an embodiment with a retaining tooth 10, the reference numeral 51 showing that a pair of retaining teeth is involved. The outer limb 6, 8 is even shorter and, in particular, the error rate in the carrying part is considerably reduced. A particular construction of the outer limbs 6, 8 which engage beneath the inner limbs 7, 9 with a nose 53 counteracts deflection against possible separating forces.

In contrast to the illustration in Fig. 11, the under-lapping securing nose or nose 53 is dispensed with in the design according to Fig. 12 owing to the extremely short lever arm of the outer limb 6. 8. Owing to the additional retaining tooth 44. 45, acting on the centrepiece 18, of the inner limb 7, 9, the total tooth thickness of the known designs of 37 mm. is achieved with far fewer complications in terms of fit and carrying content. The crest face 57 has an arcuate configuration so it rigidly surrounds the U-shaped limb of the chain link to be connected.

Non-jamming assembly of the U-shaped lock halves 2, 3 is achieved if two recesses 22, 23 are formed alternately and point-symmetrically to one another in the region of the lock joint 5 of the two inner limbs 7, 9. This has already been mentioned hereinbefore. The hook-shaped additional retaining teeth 44, 45 of the adjoining inner limbs 7, 9 are pressed into these recesses 22, 23 after the centrepiece 18 has been driven out. The two lock halves 2, 3 can therefore be separated from one another more easily. However, the back of the hook tooth or additional retaining tooth 44, 45 extends at right angles to the lock joint 5 so that it passes the coupled chain link during assembly. A terminal nose-shaped projection 62 of the outer limb 6, 8 engages in a forkshaped recess 61 in the inner limb 7, 9 to prevent transverse displacement.

Although the recesses 22, 23 are unaffected by the inserted centrepiece 18 in the construction according to Fig. 13, the design according to Fig. 14 provides a respective filling part 54, 541 in this region or fills the recesses 22, 23. A type of Z-shaped centrepiece 18 is created, but does not have the effect described with reference to the following figures.

According to Fig. 15 and 16, the centrepiece 18 is constructed as a Zshaped component 26. The square core 27 extends orthogonally to the lock joint 5. The root height of the inner limb 7, 9 increases additionally in comparison with the preceding variations. The centrepiece 18 is secured here by riveting, as shown schematically.

In comparison with the design according to Fig. 19, Fig. 16 shows a design in which the carrying core 27 of the centrepiece 18 has the form of a rhombus or parallelogram, the lateral faces 55 contacting the additional retaining tooth 44, 45 of the inner limb 7, 9 being at right angles to the right axis 56 of the flat chain joint 1. The foot thickness of the retaining tooth therefore increases from 15 mm to 20 mm. The back of the additional retaining tooth 44, 45 is designated by 59.

Fig. 17 shows a flat chain joint 1 consisting of two lock halves 2, 3 which are secured and clamped relative to one another by an interposed bolting element 4. In contrast to known chain joints, a lock joint 5 is provided here which extends centrally through the bolting element 4 in such a way that additional teeth are formed or created in the region of the bolting element 4 in addition to the retaining teeth 10, 11, 12 formed between the outer limbs 6, 8 and the inner limbs 7, 9. The tooth gaps between the retaining teeth 10, 11, 12 are designated by 13 and 14.

Fig. 17 shows that a respective pair of retaining teeth with retaining teeth 10 for each inner and outer limb 6, 7, 8, 9 is produced here. The total tooth thickness per limb is considerable, additional pairs of retaining teeth 44, 45 additionally being formed on the respectively opposed sides 15, 16 of inner limb and outer limb 6, 7, 8, 9.

A Z-shaped component 26 which serves as centrepiece 18 and ensures that the adjoining chain links engaging in the chain eyelets 19, 20 are securely mounted and guided in the chain joint or flat chain joint 1 is inserted centrally in the design according to Fig. 17 and also according to Fig. 18. The core 27 of the Z-shaped component 26 is so constructed and arranged that the above-mentioned additional pairs of holding teeth 44, 45 are produced, and the limbs 29 can be suitably long in construction. The Z- shaped component 26 can also have the overall shape of a stepped block 28.

The chain fronts 65, 66 are provided in each case with an antikink nose 67 which results in effective kink prevention in the main pulling direction. In the pivot range of 39' in the design only with the anti- kink nose 67, a kink reduction of 28% is ensured in the arc range of 140'. The crest faces 57 of the retaining teeth 10, 11, 12 are somewhat bent in design in order also to additionally counteract the risk of kinking.

A single-tooth pair of retaining teeth 49 is embodied in Fig. 17, Fig. 18 and Fig. 19, an additional catch hump 70 and catch groove 71 being provided to counteract overloading of the outer limbs 6, 8 in this way. In the construction according to Fig. 19, the tooth thickness is reduced to 22 mm so the outer limbs 6, 8 can be about 15 mm shorter in construction. The anti-kink noses, which can be seen particularly clearly in Fig. 18, are also designated by 67 here.

In contrast to the illustrations in Fig. 17 and 19, the chain joint 1 according to Fig. 20 is provided with a centrepiece 18 which is parallelogram-like in cross-section. Therefore, the additional pairs of retaining teeth 44, 45 are also produced here.

Fig. 21 shows the construction of the catch hump 70 and catch groove 71, the centrepiece 18 being secured by a screw connection not described in detail here.

Fig. 22 to 29 show chain joints 1 with a centrepiece 18 having a long supporting base 72, 73. These centrepieces 18 are also secured by a cap nut 74, as shown in Fig. 23. It is also proposed according to Fig. 25 and Fig. 26 that the groove nut 74 used is caulked after it has been appropriately tightened. Caulking of the groove nut 74 is even provided on both sides in Fig. 25. The method of fixing the centrepiece 18 can therefore also be described as central screw/shrink connection 75. A shrink ring 76 can also be used, which is shrunk onto the corresponding part of the centrepiece 18 as indicated, for example, in Fig. 23.

A centrepiece 18 which is arranged so as to extend obliquely, more specifically parallel, to the retaining teeth 10, 11, 12 is shown in Fig. 27, 28 and 29, just as in Fig. 22 and 24. Whereas the supporting base 72, 73 of the centrepiece 18 is extended by about 10 mm in Fig. 24, a certain inclination is provided in Fig. 27. In this embodiment, central part 18 and saw teeth 10, 11, 12 are inclined at 16'. In Fig. 28, the inclination is reduced to 12' so a tooth foot thickness of the tooth 12 close to the eyelet of 16 mm can be increased by 4 mm. In Fig. 29, teeth and central part 18 are also inclined at 12', but the central part 18 is thickened by 2 =. The inner limb hub is therefore uniformly 24 mm thick and also thicker in the eyelet region.

Fig. 30 and Fig. 31 correspond to one another, central part 18 and teeth 10, 11, 12 not being shown inclined but extending straight horizontally in the pulling direction. The tooth shear thickness 19 mm is 6 mm thicker and the tooth foot thickness of the tooth 12 close to the eyelet of 20 mm is 4 mm. thicker.

In the construction in Fig. 31, moreover, the central part 18 is provided with saw teeth 77 and therefore becomes a jointly carrying element. The load distribution is optimised and harmful concentrations of stress are advantageously avoided in the root base of the inner limbs 7, 9. The engagement in which the saw tooth 77 accordingly penetrates is designated by 78.

The design of the chain joint I shown in Fig. 32 corresponds to the previously described designs with regard to the basic construction except that a double-tooth pair of holding teeth is shown here in which the tooth foot is shown horizontally and undercut. A wide front cross-section to the outer limb optionally has an enlarged kink preventer. A tongue and groove catch 80 is shown here, this securing means being combined with the anti-kink noses 67. The central part 18 lies horizontally and, as described hereinbefore, is fixed in such a way that the two locks halves 2, 3 cannot fall apart after corresponding catching of the central part 18.

A tongue and groove catch 80 is also produced in the construction according to Fig. 33, undercut teeth 79 also being produced. The undercut teeth 79 produce a claw-like connection which advantageously has a pulling in effect and counteracts bending.

The design according to Fig. 18, 19 and 22 also counteracts bending, the tongue and groove catch 80 also being shown here and the particular construction of the chain fronts 65, 66 according to Fig. 20 and 21.

Fig. 39 and Fig. 40 show a particular construction in as much as additionally or only a forked catch 81 is provided in the end region of the outer limbs 6, 8, additional securing being achievable by additional shear bolts 82. This forked catch 81 is shown in particular in Fig. 43, the shear bolt 82 providing additional protection against bending but hardly being stressed in normal cases as the respective double-tooth pair of holding teeth connecting the inner and outer limbs 6, 7, 8, 9 is equipped with so-called saw teeth in a tooth foot plane preferably inclined at 4>.

Fig. 41 and 42 show that a two-part centrepiece 18 equipped with an antikink collar 85, more specifically in the eyelet region 84, can also be used. The two parts of the centrepiece 181, 1811 are effectively connected to one another and therefore also fixed by a through-bolt 86 or by two through-bolts 86, 87.

The design in Fig. 44 is a flat chain joint 1 with a singletooth construction. A catch hump 70 and catch groove 71 are provided here as well as additional securing noses 89 and forkshaped recesses 90 associated with the end 88. These securing noses 89 and fork-shaped recesses 90 provide protection against transverse displacements and rotational movements. Only this stabilised embodiment acts as additional or only anti-kink device. Fig. 44-1 shows the particular construction of these securing parts 89, 90.

Fig. 44.2 and Fig. 45 show an arcuate securing element 95 which supplements a Z-shaped moulding resembling a flash of lightning as centrepiece 18. The rectangular core of this moulding is followed by a point-symmetrical limb of which the end is convexly curved and, in operation with a concave furrow 93 of the inner limb 7, 9 of each lock half 2, 3 over or under the retaining teeth of the respectively adjacent inner limb 7, 9 form a curved channel 94 of rectangular cross-section. The curved arcuate securing element 95 can be driven into this channel 94 by hammer strokes and is then held in the fitted position by initial tension. It is also possible for the curved channel 94 to have, at both ends, grooves which are shaped into the inner limb 7, 9 and into which the arcuate securing element 95 is inserted prior to fitting so as to have a head shape 109 which is completed on one side and which comes to rest after fitting in the recess of the snap groove 112 also designed for release, whereas a limb 108 or 107 of the end 106 slit in the manner of a split pin is bent back on the opposite side of the chain joint 1 and also comes to rest in the snap groove 112 so that an advantageously interlocking connection not only of the two securing elements 95 but, in particular, also of the centrepiece 18 designed as a stepped block is achieved without a substantial loss of cross-section on the inner limbs 7, 9, so a loss of the centrepiece 18 which would endanger the reliability of operation cannot occur, in particular as the conveyor chain belt passes below the impact roller.

Fig. 31 and 33 again show corresponding designs while Fig. 30, 32 and 34 show the anti-kink collars 85 forming an upper blocking embankment 97 and a lower blocking embankment 98 in this embodiment. The position and guidance of the connecting link 83. 83T is accordingly ensured thereby.

Whereas the arcuate securing element 95 is also bent with respect to the central limb 108 according to the arcuate centrepiece 18 in the construction according to Fig. 44.2, the particular design of the centrepiece 18 according to Fig. 49 produces interlocking securing via the correspondingly bent securing element 95. The two limbs and the two ends 104, 105 of the limb 107 and 108 of the securing element 95 are also bent here in such a way that corresponding securing means is achieved here.

In the design according to Fig. 51 et seq., additional securing is achieved by the groove 99 and the tongue 100, Fig. 52 showing the construction and position thereof. Reference should be made to the particular construction of the arcuate securing element 95 with the central groove 102 and the corresponding attachment 103 in Fig. 53. Finally, Fig. 54 shows a configuration in which arcuate securing elements 95 are also used, the slit ends 106 of which are accordingly bent back while the finished head shape 109 allows simple assembly. The entity can be additionally stabilised by a bolt which is merely indicated here.

Finally, Fig. 55 shows a design with a wedge-type securing means wherein the centrepiece 18 is secured by friction by the two opposing transverse wedges 110, 111, more specifically as wedge connection which is rarely released and has a taper of 1:25.

It should be added with respect to the design in Fig. 48 that sickleshaped front attachments 91 or front thickenings 92 can be produced similarly to the anti-kink nose 67 according to Fig. 50. The sickleshaped front thickenings 92 of the chain j oint 1 corresponding to the groove width of the sprocket wheel contribute to kink prevention and increase the strength in the respective joint region of the flat chain joint 1 in the form of an addition for wear. Kinking of the connecting link 83 is therefore prevented together or also alone with the anti-kink collar 85. The hingeability of 40' allows the use of six-tooth sprocket wheels with a hinge angle of 30'.

The anti-kink nose 67 which has already been mentioned several times, can be adapted to the furrow width of the sprocket wheel and has a profile of > 60', preferably 80' is achieved with the design according to Fig. 50. This anti-kink nose 67 restricts the risk of kinking to such an extent that it is fully effective to a certain extent even without the anti-kink collar 85. This design also allows the use of six-tooth sprocket wheels and all functional degrees of freedom for conveyors and plough chains required for running through curved and arcuate channels, roller curves, return loops and over sprocket wheels and return rollers.

All the aforementioned features, including those which can be inferred only from the drawings, are considered to be essential to the invention alone and in combination.

Claims

1. Chain joint for round-link chains, in particular for roundlink chains used in underground mining and tunnelling, comprising two U-shaped lock halves (2, 3) and a bolting element (4) which can be inserted into the lock joint (5) between the lock halves (2, 3) equipped alternately on the outer limbs (6, 8) and inner limbs (7, 9) with intermeshing retaining teeth (10, 10', 11, 11', 12, 12') in the closed state, characterised in that the lock joint (5) is substantially closed and in that the two mutually opposed sides (15, 16) of the inner limb (7, 9) of the lock halves (2, 3) are designed to intermesh in the manner of teeth in the region of the bolting element (4) designed as a centrepiece (18) and to enclose the centrepiece (18).

2. Chain joint according to claim 1, characterised in that the lock joint (5) between the two lock halves (2, 3) extends obliquely and diagonally through the centre of the halves and therefore also of the centrepiece (18) and therefore acts tangentially on the semicircular chain eyelet (19, 20) of each lock half (2, 3).

3. Chain joint according to any of the preceding claims, characterised in that recesses (22, 23) are provided alternately to the lock joint (5).

4. Chain joint according to claim 3, characterised in that the height of the recesses (22, 23) is adjusted to correspond substantially to the depth of the retaining teeth (10, 11, 12).

5. Chain joint according to any of the preceding claims, characterised in that the centrepiece (18) has the form of a rectangular rod.

6. Chain joint according to any of the preceding claims, characterised in that the centrepiece (18) is designed as a Zshaped component (26) and the lock joint (5) is adapted thereto, the core (27) extending orthogonally to the lock joint (5).

7. Chain joint according to any of the preceding claims, characterised in that the centrepiece (18) has the form of a stepped block (28).

8. Chain joint according to any of the preceding claims, characterised in that the centrepiece (18) is in the form of two stop bushes (30, 31) of which the flanges (32) have a hexagonal shape and in whose central bore (33) a cylinder head screw (35) and an opposing hexagon nut (34) can be inserted.

9. Chain joint according to any of the preceding claims., characterised in that the centrepiece (18) has the form of a stop bush (30') with central bore (33) for a cylinder head screw (35) and a cap nut (36).

10. Chain joint according to any of the preceding claims, characterised in that the centrepiece (18) has the form of two conical bushes (38, 39) with a central bore (33) into which a cylinder head screw (35) or hexagon nut (34) can be inserted.

11. Chain joint according to any of the preceding claims, characterised in that the centrepiece (18) has the form of a stepped block (28) and collar plates (40) with central bore (33) into which a countersunk rivet (41) can be inserted.

12. Chain joint according to any of the preceding claims, characterised in that the additional retaining teeth (44, 45) formed in the region of the centrepiece (18) have an average thickness of 16 to 18 mm.

13. Chain joint according to any of the preceding claims, characterised in that the crest part (47) of the retaining teeth (10, 11, 12) of the inner limb (7, 9) is designed to have the same slope as the lock joint (5).

14. Chain joint according to any of the preceding claims, characterised in that the retaining teeth (10, 11, 12) of the inner and outer limbs (6, 7, 8, 9) are shaped so as to form saw teeth (48).

15. Chain joint according to any of the preceding claims, characterised in that the inner limbs (7, 9) are designed to rest on one another with their locking faces (49, 50) with an angle of deviation of about 24.4' obliquely to the pulling direction so as to close the lock joint (5).

16. Chaih joint according to any of the preceding claims, characterised in that each pair of retaining teeth (51) comprises a retaining tooth (52) in addition to the jointly carrying centrepiece (18).

17. Chain joint according to any of the preceding claims, characterised in that the outer limb (6, 8) is designed to engage beneath the inner limb (7, 9) with a nose (53).

18. Chain joint according to any of the preceding claims, characterised in that the core (27) of the Z-shaped component (26) has the form of a rhombus or parallelogram, the lateral faces (55) extending at right angles to the right axis (56) and the crest faces (57) parallel to the lock joint (5).

19. Chain joint according to claim 3, characterised in that the back (59) of the additional retaining tooth (44, 45) created in the region of the centrepiece (18) extends at right angles to the lock joint (5).

20. Chain joint according to claim 3, characterised in that the noseshaped projection (62) engaging in a corresponding recess (61) in the inner limb (7, 9) is provided at the end of the outer limb (6, 8).

21. Chain joint according to any of the preceding claims, characterised in that the chain fronts (65, 66) are provided with a respective anti- kink nose (67).

22. Chain joint according to any of the preceding claims, characterised in that the anti-kink nose (67) is designed to produce a kink-free pivot zone of about 40% and preferably extends over 45 mm for this purpose.

23. Chain joint according to any of the preceding claims, characterised in that, with a design with single-tooth pairs of retaining teeth (69), the tooth thickness is reduced from 30 to 2 2 mm.

24. Chain joint according to any of the preceding claims, characterised in that the centrepiece (18) is parallelogram-like in cross-section.

25. Chain joint according to any of the preceding claims, characterised in that the inner limb (7, 9) is equipped with catch humps (70) and the outer limb (6, 8) with correspondingly designed catch grooves (71).

26. Chain joint according to any of the preceding claims, characterised in that the centrepiece (18) has a long supporting base (72, 73) and is equipped with a central screw or shrink connection (75).

27. Chain joint according to any of the preceding claims, characterised in that the retaining tooth (12) of the inner limb (7, 9) close to the eyelet is reinforced and arcuate in design.

28. Chain joint according to any of the preceding claims, characterised in that the saw tooth-shaped retaining teeth (10, 11, 12) and the centrepiece (18) have the same or a different inclination.

29. Chain joint according to any of the preceding claims, characterised in that the centrepiece (18) and the saw toothshaped retaining teeth (10, 11, 12) are designed to extend horizontally in the pulling direction.

30. Chain joint according to any of the preceding claims, characterised in that the centrepiece (18) is provided, on both sides, with saw teeth (77) which are designed to carry jointly and engage in the inner limbs (7, 9).

31. Chain joint according to any of the preceding claims, characterised in that the retaining teeth (10, 11, 12) have undercut teeth (79).

32. Chain joint according to any of the preceding claims, characterised in that the outer retaining teeth (10) have an oblique tongue and groove catch (80) extending parallel to the inclination of the teeth.

33. Chain joint according to any of the preceding claims, characterised in that the outer retaining teeth (10) are designed to produce a forked catch (81).

34. Chain joint according to any of the preceding claims, characterised in that the forked catch (81) is secured by a shearing bolt (82).

35. Chain joint according to any of the preceding claims, characterised in that the anti-kink noses (67) are designed to produce an enlarged antikink zone and adhere to a lock thickness of c = 41.

36. Chain joint according to any of the preceding claims, characterised in that the centrepiece (18) is designed to have an anti-kink collar (85) in the eyelet region (84).

37. Chain joint according to any of the preceding claims, characterised in that the centrepiece (18) is designed in two parts with a long supporting base (72, 73) and is secured by one or two through-bolts (86, 87).

38. Chain joint according to any of the preceding claims, characterised in that a securing nose (89) is provided at the end (88, 88') of the outer limb (6, 8) and the inner limb (7, 9) of each lock half (2, 3), the securing nose (89) being arranged and designed to engage in a fork-shaped recess (90) of the front attachment (91) of the respectively adjacent lock half.

39. Chain joint according to any of the preceding claims, characterised in that the long limbs of the Z-shaped component (26) are shaped so as to be convexly curved at the end in a plan view and, together with a furrow (93) associated with the inner 1 imb (7, 9), to form a channel (94) into which an arcuate securing element (95) can be driven.

40. Chain joint according to any of the preceding claims, characterised in that the ends (88) of the inner limbs (7, 9), in particular when designed as a double-hook tooth, are designed to limit the chain eyelet (19, 20) of the adjacent lock half substantially circularly via an anti- kink collar (85).

41. Chain joint according to any of the preceding claims, characterised in that the anti-kink collar (85) is formed by a concave envelope curve which therefore forms two blocking embankments (97, 98).

42. Chain joint according to any of the preceding claims, characterised in that the chain fronts (65, 66) have a sickleshaped front thickening (92).

43. Chain joint according to any of the preceding claims, characterised in that the retaining tooth (10) of the outer limb (6, 8) has a central groove (99) extending continuously in the longitudinal direction of the lock (1), and the associated tooth gap (13) of the inner limb (7, 9) has a correspondingly shaped tongue (10).

44. Chain joint according to any of the preceding claims, characterised in that the tongue (100) is connected interchangeably to the inner limb (7, 9).

45. Chain joint according to any of the preceding claims, characterised in that the Z-shaped centrepiece (18) is designed as a stepped block (28) and a securing element (95) with a correspondingly shaped attachment (103) can be driven between it and the inner limb (7) having a central groove (102), the ends (104, 105) of the securing element (95) being designed to bend down in the direction of the stepped block (28).

46. Chain joint according to any of the preceding claims, characterised in that the securing element (95) has a finished head shape (109) on one side, is slit in the manner of a split pin on the opposite side and has limbs (107, 108) which can be bent down in both directions.

47. Chain joint according to any of the preceding claims, characterised in that the centrepiece (18) is fixed via two