OA22018A - Plate For Joining Two End Portions Of A Conveyor Belt, Joining Device Comprising At Least One Such Joining Plate, And Associated Strip Of Joining Plates. - Google Patents

Abstract

The invention relates to a joining plate (4) for a joining device (1) for a conveyor belt (2) intended to connect two end portions (21, 22) of at least one conveyor belt (2), the joining plate (4) having an outer surface (S1) intended to be flush with a useful surface of the conveyor belt (2) in the joining position and an inner surface (S2) opposite the outer surface (S1) and intended to at least partially cover the two end portions (21, 22) of the conveyor belt (2) in the joining position, the joining plate comprising: a body (45) made of flexible material, having an outer surface forming the outer surface (S1) of the joining plate (4); a reinforcement plate (11) having fastening throughholes, rigidly connected to the body; and a plural ity of inserts (6) at least partly embedded in the body (45) and each having a fastening opening associated with one of the fastening holes, so as to surround a rim of the associated fastening hole on one side of the reinforcement plate (11), for accommodating fastening means (5) of the joining device (1) with the end portions (21, 22); the joining plate (4) being characterized in that the body (45) at least partly covers the fastening openings of the inserts. <img file="OA22018A_A0001.tif"/> Fig. 3c

Description

articulation rod then being passed inside the interleaved knuckles so as to thus connect the two ends by forming a type of hinge. The known means used to fasten the Staples on the ends of the conveyor belt are made up of rod fastening means such as studs, rivets and screws.

[0007] In the more recent past, joining devices hâve been proposed that use fiat connecting 5 éléments, generally made of reinforced elastomer or of reinforced synthetic material, respectively disposed on either side of the ends of the conveyor belt and fastened on said ends to be connected. Examples of such joining devices are provided in patents EP-0827575-B1 and EP-l 163459-B1. These devices comprise an upper joining plate and a lower joining plate, optionally connected by a central portion. These lower and upper joining plates hâve a spacing I0 that is designed to engage the respective end of a conveyor belt therein, by causing it to approximately corne into abutment against the central portion, or even, in the event that the joining device does not hâve a central portion, against a spacer provided for this purpose during assembly, then subsequently removed. In other words, these joining devices comprise two pairs of fastening wings facing each other, with the ends of the conveyor belt being respectively 15 introduced between two wings of the same pair. Fastening the lower and upper parts forming a joining plate on the ends of the conveyor belt is generally carried out by means of rivets, spikes, studs, screw-nut Systems, or even by cold bonding or by fiat vulcanization of the wings against the fiat outer surfaces of the conveyor belt engaged between the wings.

[0008] The joining devices are generally made of a flexible and résilient material, for example, 20 of vulcanized rubber, or of a synthetic material, such as polyuréthane, in which a reinforcement, generally a textile reinforcement, is embedded, having extensibility in the longitudinal référencé direction of the conveyor belt.

[0009] The extensibility ofthe reinforcements for this type of joining device, in the longitudinal direction of the conveyor belt, is intended to allow the joining devices mounted on the conveyor 25 belts to repeatedly cross, without any excessive wear or fatigue that could lead to rapid détérioration, the curved parts of the path of the conveyor belts, namely, the curvature of the drive rollers, the retum rollers and the tensioning rollers. Indeed, during this operation, the upper part of the joining devices expériences a tensile force, while their lower part (i.e., the part oriented toward the outer surface of the rollers) expériences a compressive force, and this is 30 due to the différence in the path of these parts, with these paths being directly proportional to the radius of curvature, which varies due to the thickness of the joining devices.

[0010] Since the stresses are quite different between the lower and upper parts, and in order to further improve the wear résistance of these joining devices, the Applicant has improved their product in the past so as to provide the upper part with greater extensibility than that of the lower part. In this type of conveyor belt junction, the central portion has then evolved so as to 5 be detached from the lower and upper plates, in order to leave room for the use of independent spacers, which are used during assembly and against which the first one of the ends of the conveyor belt that is placed in the junction cornes into abutment, between the lower and upper plates, then these spacers are removed before the second one of the ends of the conveyor belt is installed. Indeed, the joining devices were produced by molding or by injection and had an 10 H-shaped structure, the lower and upper plates and the central portion of which were formed as a single piece. ïn order to manufacture them this would require as many molds as the thicknesses of the conveyor belts encountered in the fieid, and these joining devices consequently had to be manufactured in very small production runs, which increased the cost price for manufacturing, storage and distribution.

[0011] This problem, namely that of the plethora of molds and molded products required for the various thicknesses of conveyor belts, has been solved, notably by producing, as explained above, the joining devices in three separate parts: a part forming upper left and right wings forming a single piece, a part forming lower left and right wings forming a single piece, and an intermediate part, corresponding to the middle bar of the H-shaped profile, with this 20 intermediate part forming a spacer. In such a configuration it is then possible to manufacture the two lower and upper plates in isolation, and each is configured so as to be adapted to the forces that they expérience (compressive/tensile forces) and to the associated stresses. For example, the lower plate is arranged to pass over drive rollers, retum rollers and tensioning rollers without experiencing any damage, with said rollers driving or returning the conveyor 25 belt to the ends where the considered joining device is mounted, with the lower plate coming into direct contact with these components for driving the belt. For its part, the upper plate is in direct contact with the various materials or the various products conveyed on the conveyor belt. Furthermore, the upper plate is also generally swept by wipers.

[0012] In any case, extensibility has become a prédominant feature in the design of such a 30 joining plate with a view to obtainîng a sufficiently flexible and résilient joining device that is able to pass over drive rollers and retum rollers without experiencing any damage, while being provided with tensile strength that allows it to withstand ail the forces that it expériences without being damaged. These features of extensibility and of résistance to such forces for the joining plate are conferred both by the flexible and résilient material (vulcanized rubber, synthetic material such as polyuréthane) formîng the joining plate and by the reinforcement that is integrated therein, offering both extensibility in the longitudinal direction of the conveyor belt and résistance that is adapted to withstand the greater tensile forces experienced by the conveyor belt.

[0013] Despite the progress that has been made conceming the extensibility of such a joining plate, the Applicant is constantly developing their product in order to increase the flexibility and to improve the dynamic behavior of a joining device. It has been found that the fastening means (such as screws or rivets) securing the joining plates signifîcantly affect the stiffness of the joining plates, and more generally of the joining device. This constraint is even more signifïcant in some applications, such as for conveyor belts called high-endurance coating conveyor belts. Indeed, in order to improve abrasion résistance and to increase the service lîfe of the conveyor belt, a known configuration of a conveyor belt involves the layer of flexible and résilient material covering over the reinforcement, for example a textile reinforcement, being thickerthan the layer of flexible and résilient material located under said reinforcement. In other words, the reinforcement is not located at the center of the thickness of the belt but is offset toward the face of the conveyor belt that cornes into direct contact with the components for driving the conveyor belt. For this type of application, the means for fastening the joining plates of a given joining device each pass through one of the joining plates, one of the end portions of the conveyor belt, then the other one of the joining plates. The length ofthe fastening éléments is limited by the thickness ofthe joining plates together with the end portion, notably to ensure that the fastening means are correctly housed in the inserts that are at least partly incorporated into the upper and lower plates. The resuit of such a limitation is the presence of as many fastening interfaces as there are fastening éléments on the outer surfaces of the associated joining plate, with interfaces representing zones that become conducive to the appearance of defects in the material of the joining plate, for example cracks. Furthermore, the mobility of the fastening means during the passages of the retum components of the conveyor belt involves an increased mechanical stress on the material of the upper joining plate, which is also a source of prématuré wear.

DISCLOSURE OF THE INVENTION

[ 0014] The invention aims to overcome ail or some of the disadvantages of the prior art by notably proposing a solution for improving the flexibility of the joining devices, while further improving their structural strength in order to improve their operating duration, and thus further limit any maintenance operations.

[0015] To this end, according to a ftrst aspect of the invention, a joining plate is proposed for a joining device for a conveyor belt intended to connect two end portions of at least one conveyor belt, the joining plate having an outer surface intended to be flush, i.e., level, with a useful surface of the conveyor belt in the joining position and an inner surface opposite the outer surface and intended to at least partially cover the two end portions of the conveyor belt in the joining position, the joining plate comprising:

- a body made of flexible material, having an outer surface forming the outer surface of the joining plate;

- a reinforcement plate having fastening through-holes, rigidly connected to the body; and

- a plurality of inserts at least partly embedded in the body and each having a fastening opening associated with one of the fastening holes, so as to surround a rim of the associated fastening hole on one side of the reinforcement plate, for accommodating fastening means of the joining device with the end portions;

the joining plate being noteworthy in that the body at least partly covers the fastening openings 20 of the inserts.

[0016] By virtue of such a combination of features, the joining plate is thus devoid of inserts and/or fastening éléments in an upper part that is only formed by the body of the joining plate, which provides it with increased flexibility and better dynamic behavior, in particular for the passage of the drive components and the retum components, such as the rollers of a conveyor carnage or of a conveyor. In this way, irrespective of the total thickness of the joining plate adapted to a determined joining operation, it is possible to limit the impact of the fastening éléments on the flexibility of the junction. With the length of the fastening éléments of a joining device comprising such a joining plate thus being independent of the thickness of the joining plate, the stiffhess of the joining plate can be limited.

[0017] According to one embodiment, the body has a minimum thickness, measured between the outer surface and the inserts, that is greater than or equal to a distance equal to a height of the associated inserts. Preferably, this minimum thickness is at least a few millimeters.

[0018] According to one embodiment, the joining plate has an outer surface formed by an outer surface of the body and an inner surface opposite the outer surface and formed by an inner surface of the body and/or of the reinforcement plate, the outer surface and the inner surface being équidistant from each other on either side of a middle plane of the joining plate, the reinforcement and the inserts being positioned on the inner side of the joining plate relative to the middle plane, for example between the middle plane and the inner surface.

[0019] The middle plane of the joining plate delimits an upper half of the joining plate located on the side of the outer surface of said joining plate relative to the middle plane of a lower half of the joining plate located on the side of the inner surface of said joining plate relative to the middle plane, with the distance separating the outer surface and the inner surface of the body delimiting a thickness of the joining plate.

[0020] According to one embodiment, the reinforcement plate and the inserts are housed on the side of the lower half of the joining plate relative to the middle plane, at least partly, or even fully, in the lower half of the joining plate relative to the thickness thereof, on the side of the inner surface.

[0021] The thickness of the joining plate is therefore delimited by the distance between the outer and inner surfaces of said plate. The lower half of the thickness in this case désignâtes the “lower half’ of the associated joining plate, and in particular of the body of the joining plate. By contrast, the upper half of the joining plate, and in particular ofthe body of the joining plate, is located above the lower half.

[0022] By virtue of such a combination of features, the joining plate is thus devoid of inserts and/or fastening éléments in its upper half, further improving its extensibility in this zone that expériences the most stress during the passage of the drive components and of the retum components.

[0023] According to one embodiment, the reinforcement plate is housed in the body and extends at a constant distance from the outer surface. The reinforcement plate can be integrally housed in the body so that the inner surface of the joining plate is simply formed by an inner surface of the body itself. Altematively, the reinforcement plate can be positioned flush with the inner surface of the joining plate, which is then formed by an inner surface of the joining plate, or even also of the body.

[0024] According to one embodiment, the reinforcement plate is textile, Le., it comprises, preferably is formed by, at least one layer, or even a plurality of layers, of textile. The 5 reinforcement plate, or reinforcement, thus forms a woven reinforcement improving the résistance of the joining plate to the tensile forces.

[0025] According to one embodiment, the body is formed from an elastomer material, preferably made of rubber, and has extensibility ranging between 15% and 40%, preferably between 20% and 30%.

|0026] According to one embodiment, the body of the joining plate has holes extending from the inner surface of the body in the lower half of the joining plate, the holes being configured to partly house the fastening means. These holes in line with each of the inserts each at least emerge on the side of the inner surface of the joining plate, but they can remain located in the lower half of the plate. In this configuration, an upper part of the joining plate supporting the outer surface, preferably the upper half thereof, can be devoid of holes. This reduces the number of zones conducive to the appearance of defects, for example cracks. The dynamic behavior of the joining plate and of the whole device is thus improved.

[0027] According to one embodiment, the body of the joining plate comprises through-holes, extending from the outer surface of the body of the joining plate toward the inner surface of the 20 joining plate, the holes being configured to be each traversed by one of the fastening means.

Preferably, the through-holes are cylindrical. Such through-holes are located in line with each of the inserts and thus each provide a lane function for routing the fastening means toward the associated insert.

[0028] According to one embodiment, a diameter of each through-hole is configured so as to 25 be strictly less than a diameter ofthe fastening openings ofthe associated insert so that the body partly covers said fastening openings of the inserts. By virtue of the resilience of the material forming the body of the joining plate, it would appearthat each hole is configured to resiliently deform when one of the fastening éléments passes through or is introduced into said hole, with the associated hole being delimited by the body of the joining plate and then retuming to its 30 initial shape once the fastening element has been removed, when the plate and the device are assembled in the joining position and each fastening element coopérâtes with the associated insert. In practice, and unlike received opinion, résistance tests hâve shown that the fastemng éléments do not cause prématuré wear due to any friction with the body of the joining plate.

[0029] According to one embodiment, each of the through-holes is coaxial with one of the fastening openings of one ofthe associated inserts ofthe joining plate. Preferably, each throughhole is also coaxial with the associated fastening hole of the reinforcement plate.

[0030] According to another aspect of the invention, the invention relates to a joining device for a conveyor belt intended to connect two end portions of at least one conveyor belt, the joining device being noteworthy in that it comprises at least one joining plate as described above.

[0031] According to one embodiment, the joining device for a conveyor belt comprises a first joining plate according to any of the aforementioned embodiments and a second plate comprising a plurality of inserts, the two plates being configured to each cover a separate side of the ends of the conveyor belt so that said conveyor belt is disposed between the two joining plates in the joining position, the first and second joining plates being fastened together by fastening means arranged to at least partly respectively penetrate a joining plate from among the first and the second joining plate, one of the ends of the conveyor belt and then the other joining plate from among the first and the second joining plate.

[0032] According to one embodiment, a thickness of the first joining plate is greater than or equal to, preferably strictly greater than, a thickness of the second joining plate of the joining device, preferably greater than or equal to twice the thickness of the second joining plate, more preferably greater than or equal to three times the thickness of the second joining plate. According to the technical language of the technical field, such a configuration is referred to as a “high-endurance coating” plate. In such a configuration, the high-endurance coating is supported on the upper joining plate of the joining device.

[0033] According to one embodiment, the fastening means comprise rod fastening means, preferably ofthe screw type, the fastening means each preferably comprising a head configured to cooperate with a portion of the inserts and an anchoring section, preferably provided with a thread, configured to cooperate with another portion of the inserts. In alternative and/or additional configurations, the fastening means can comprise rivets.

[0034] According to one embodiment, the inserts configured to each cooperate with a head of the fastening means each comprise a washer perforated by the associated fastening opening surrounded by a cup able to house the head of the fastening means.

[0035] According to one embodiment, the inserts configured to each cooperate with an 5 anchoring section of the fastening means each comprise a cylindrical tubular portion delimiting the associated fastening opening for which an inner cylindrical surface is able to cooperate with an anchoring section of the fastening means, the inner cylindrical surface preferably comprising a tapping.

[0036] According to one embodiment, the first plate only comprises the tapped inserts 10 configured to cooperate with the threaded anchoring sections of the fastening means.

Altematively, the first joining plate only comprises inserts configured to cooperate with the heads of the fastening means.

[0037] According to one embodiment, the through-holes are each coaxial with the fastening openings of each associated pair of inserts of the first plate and of the second plate, in the joining 15 position, when the first and second joining plates are in a joining position. Such a configuration allows vertical alignment ofthe inserts of each pair of inserts associated with a given fastening means in order to allow it to be anchored.

[0038] According to one embodiment, a diameter ofthe through-holes is strictly smallerthan a diameter of the fastening opening of the associated insert, preferably strictly less than an outer 20 diameter of the head of the associated fastening element, preferably strictly less than a nominal diameter of the anchoring section of the associated fastening element, more preferably substantially equal to the thread root diameter of the thread of the anchoring section of the associated fastening element.

[0039] According to another aspect of the invention, the invention relates to a method for 25 manufacturing a joining plate according to any of the embodiments described above, characterized in that it comprises at least the following steps of:

- manufacturing a continuous sériés of a plurality of joining plates in strip form; and

- cutting, from said strip thus manufactured, joining plates according to predetermined dimensions.

[0040] Such a manufacturing method is particularly advantageous in that it allows continuous manufacturing of several successive joining plates. Each of the first and second joining plates,

ΙΟ intended to form the lower and upper joining plates of the joimng device, is then eut into an associated strip or strip portion thus manufactured and specifically adapted to the desired use.

[0041] According to another aspect, the invention also relates to a method for joining a first end portion and a second end portion of a conveyor belt using a joining device for a conveyor belt as described above, comprising a first joining plate according to the invention and a second joining plate, characterized in that it comprises at least:

- a step involving the first joining plate and the second joining plate each covering a separate side of the end portions of the conveyor belt so that said conveyor belt is vertically interposed between the two joining plates, said first and second joining plates fortning a first pair of wings that is adapted to clatnp the first end portion of the conveyor belt and a second pair of wings that is adapted to clamp the second end portion of the conveyor belt;

- a step of inserting the second end of the conveyor belt between two wings of the second pair of wings;

- a step of fastening the second end portion of the conveyor belt with the two wings of the second pair of wings between which it is positioned;

- a step of inserting the first end of the conveyor belt between the two wings of the first pair of wings;

- a step of fastening the first end of the conveyor belt with the two wings of the first pair of wings between which it is positioned.

BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Further features and advantages of the invention will become apparent upon reading the following description, with reference to the appended figures, which illustrate:

- figure 1 : a plan view of a joining device for a conveyor belt of the prior art, as a top view;

- figure 2: a longitudinal section view, along section A-A of figure 1, of a joining device, showing an exploded view of its various constituent éléments;

- figure 3a: a longitudinal section view of a joining device for a conveyor belt according to a first embodiment, showing an exploded view of its various constituent éléments;

- figure 3b: a longitudinal section view of a joimng device according to the same embodiment, in an intermediate assembly position;

- figure 3c: a longitudinal section view of a joining device according to the same embodiment, in a joining position;

- figure 4a: a longitudinal section view of a joining device for a conveyor belt according to another embodiment of the invention, showing an exploded view of its various constituent éléments;

- figure 4b: a longitudinal section view of a joining device according to the same embodiment of the invention.

[ 0043] For greater clarity, identical or similar éléments are identified using identical reference signs throughout ail the figures.

[ 0044] in the description and the daims, in order to clarity the description and the daims, the longitudinal, transverse and vertical terminology will be adopted in a non-limiting manner with reference to the X, Y, Z trihedron shown in the figures.

[ 0045] Furthermore, the tenus “upper”, “lower” and their dérivatives refer to the position or to the orientation of an element or of a component, with this position or this orientation being considered when the joining plates are in the service configuration and extend in a horizontal plane.

DETAILED DESCRIPTION OF EMBODIMENTS

[ 0046] Figure l is a plan view, from above, of a joining device 1 according to the prior art and shows an upper joining plate 4 of a joining device 1. The heads 5a of the screws 5 that form an example of means for assembling the joining devices also can be seen.

[0047] The cutouts lia and 11b show two types of textile-type reinforcements, which are woven: in the reinforcement lia, the fabric is disposed in such a way that its weft threads, or even its warp threads, are at least approximately oriented in the longitudinal direction of the joining device 1, while in the reinforcement 11b the fabric is disposed so that its weft threads and its warp threads are oblique relative to the longitudinal direction of the joining device 1.

[0048] By way of a reminder, by convention the longitudinal direction X of the joining device 1 corresponds, in the présent description, to the longitudinal direction X of the conveyor belt 2, with the joining device 1 being mounted on the ends 3 of the conveyor belt 2 that it connects.

The transverse direction Y of the joining device 1 is, according to the same convention, the direction perpendicular to the longitudinal direction X. This convention is applied irrespective of the effective dimensions of the joining device 1 in these two directions.

[0049] The joining device of figure 1 is made up of three éléments: an element forming an upper joining plate 4, an intermediate element 9 located under the middle part of the joining plate 4, which is not visible in figure 1 other than by the two dashed lines located on either side of the two middle screws 5 delimiting, under the upper joining plate 4, the edges of the ends of the conveyor belt 2 to be connected, and an element forming a lower joining plate 4, not shown in figure 1, which is located under the intermediate element 9 and under the element forming the upper joining plate 4.

|0050] The exploded section of figure 2 successively shows assembly screws 51 forming fastening means 5, the upper joining plate 4a, inserts 6 incorporated in the upper joining plate 4, the intermediate element 9 comprising an incorporated through-bushing, vertically disposed along a vertical axis Z, with the lower plate 3 comprising tapped inserts 7.

[0051] The inserts 6 arranged to accommodate the heads 5a of screws 51 are generally in the form of perforated washers 61 comprising a cup able to house the heads 5a of the screws 5 intended to pass into the hole of the perforated washers. The central insert 6’ is generally in the form of the inserts 6 but it comprises a central tubular portion, the inner cylindrical surface of which is able to allow through the corresponding screw 5, with very little clearance, with this screw therefore not being screwed into the insert 6’. The central tubular portion of the insert 6’ protrudes from the lower surface of the upper joining plate 4.

[0052] The inserts 7 each comprise a central tubular portion, the inner cylindrical surface of which is tapped and is able to accommodate a screw 51 screwed into the tapping, with said central tubular portions protruding from the upper surface of the lower joining plate 4 of the joining device 1. The middle inserts 7’ of the lower plate are in the form of the inserts 7.

[0053] Figures 3a, 3b and 3c illustrate a joining device 1 according to a first embodiment of the invention. The joining device 1 comprises a first joining plate 4. In this embodiment, the joining device 1 also comprises a second joining plate 4’. These first and second joining plates 4, 4’ each hâve a body 45 made of a flexible and résilient material, for example made of vulcanized rubber, or of a synthetic material such as polyuréthane, and they comprise a reinforcement plate 11 rîgidly connected to the body 45 of the associated joining plate 4, 4’. The reinforcement

plate 11 is made up of one or more textile layers, so as to form a woven reinforcement. This material forms the body of each of these two joining plates 4, 4’. The reinforcement plate 11 comprises fastening through-holes each surrounding at least the fastening means 5 in the joining position, or even also a given insert.

[0054] The joining plates 4, 4’ are configured to each cover a separate side of end portions 21, of a conveyor belt 2, so that the conveyor belt 2 is vertically interposed between the first and second joining plates 4,4’. The first and second joining plates 4, 4’ together form a first pair of wings 40, which clamp the first end portion 21 of the conveyor belt 2, and a second pair of wings 42, which clamp the second end portion 22 of the conveyor belt 2 in a joining position.

The two joining plates 4, 4’ are fastened together with the end portions 21, 22 of the conveyor belt 2 by fastening means 5 arranged to at least partly penetrate the first upper joining plate 4, the end portions 21, 22 and then the second lower joining plate 4’, respectively.

[0055] The first joining plate 4 comprises a body 45 made of a flexible and résilient material such as rubber. The first joining plate 4 has an outer surface SI intended to be flush, i.e., level, 15 with a useful surface of the conveyor belt 2 in the joining position. The outer surface SI in this case is formed by an outer surface of the body. The useful surface of the conveyor belt 2 corresponds to the surface of the conveyor belt 2 on which the various conveyed materials or products rest. The first joining plate 4 also has an inner surface S2, opposite the outer surface SI and in this case is formed by an inner surface of the body and of the reinforcement plate 11.

The inner surface S2 is intended to cover a separate side of the two end portions 21, 22 of the conveyor belt 2 in the joining position, so as to straddle over these two end portions 21, 22. The inner and outer surfaces SI, S2 delimit a thickness E of the associated joining plate 4.

[0056] The thickness E of the first joining plate 4 is greater than a thickness of the second joining plate 4’, preferably greater than or equal to twice the thickness of the second joining 25 plate 4’, more preferably greater than or equal to three times the thickness of the second joining plate 4’. Such a joining plate 4 is refened to as a “high-endurance coating” plate. The reinforcement plate 11 of the joining plate 4 is housed inside the body 45 of the joining plate and extends parallel to the outer surface SI. In this case, the thickness of the second lower joining plate 4’ is defined, and therefore measured, in a manner similar to that of the first upper 30 joining plate 4, between its outer and inner surfaces in a zone without an insert, with the outer surface this time being flush with an inner surface of the conveyor belt 2 in the joining position intended to come into contact with the retum and drive components of said conveyor belt 2 opposite the usefiil surface of said conveyor belt 2.

|0057| The first joining plate 4 forming the upper joining plate of the joining device further comprises a plurality of inserts 6 for at least partly accommodating the fastening means 5 of the joining device 1, with at least the end portions 21, 22. These inserts 6 are at least partly embedded in the body 45 and each hâve a fastening opening associated with one of the fastening holes of the reinforcement plate 11, so as to surround a rim of the associated fastening hole on one side of the reinforcement plate 11, in order to accommodate means 5 of the joining device 1, with at least the end portions 21, 22.

[0058] The reinforcement 11 and the inserts 6 are housed in a lower half of the joining plate 4 relative to its thickness E adjoining the inner surface S2, preferably by means of a vnlcanization method. The terni “lower half’ is understood to mean a portion of the joining plate 4 that extends from the inner surface S2 to a middle 1 imit équidistant from the inner and outer surfaces SI, S2, with this middle limit forming a joining plane P of the joining plate 4. The lower half is opposite the “upper half’ of the joining plate 4 relative to this middle plane P, which upper half overlays the lower half. The upper half of the joining plate 4 is thus formed by the single constituent material of its body 45 and is strictly devoid of inserts or fastening éléments 5, which gives the first joining plate 4 increased flexibility and better dynamic behavior, in particular in contact with drive and retum components. This upper part is also the part that expériences the most résilient deformation when a portion of the conveyor belt passes over a retum component, offering both significant extensibility in the longitudinal direction of the conveyor belt and suitable wear résistance, since a thickness of the material of the body 45 located above the reinforcement plate 11 and the inserts 6 is relatively high due to the fact that it is a high-endurance coating plate. In particular, the body 45 has a minimum thickness, measured between the outer surface SI and the inserts 6, that is greater than or equal to a distance equal to a height of the associated inserts 6. This provides a good compromise between resilience and résistance.

|0059] In the embodiment described with reference to figures 3a, 3b and 3c, the body 45 comprises through-holes 47 extending in line with each of the inserts 6, from the inner surface SI of the body where they emerge toward the inner surface S2 of the body 45. These throughholes 47 of the joining plate 4 hâve a cylindrical shape and are erected generally vertically. The through-holes 47 are configured to be traversed by the fastening means 5 of the joining plate 4 lengthwise. The extensibility of the body 45 ranges between 15% and 40%, preferably between 20% and 30%, so that the through-holes 47 resiliently deform when they are traversed by the fastening éléments 5. In this case, each through-hole 47 is oriented so as to be coaxial with an opening for fastening an associated insert 6 of the first joining plate 4 and an associated fastening hole of the reinforcement plate 11. Each through-hole 47 continuously extends as far as the fastening opening of the associated insert 6, itself surrounding an associated fastening hole of the reinforcement plate 11. In such a configuration, the through-holes 47 delimited by the body 45 each provide a lane function for routing the fastening means 5 to the associated insert 6 of the joining plate 4 with which it can cooperate.

[0060] Like the first joining plate 4, the associated second joining plate 4’ comprises a plurality of inserts 7, preferably vulcanized.

[0061] The fastening means 5 of the joining device 1 each comprise a head 5a configured to cooperate with a portion of the inserts 6, 7 and an anchoring section 5b in order to cooperate with the other portion of the inserts 6, 7.

[0062] In general, each joining plate 4, 4’ of the joining device 1 comprises first interfaces for cooperating with the heads 5a of the fastening means 5 and second interfaces for cooperating with the anchoring sections 5b of the fastening means 5, with the second interfaces being separate from the first interfaces and comprising inserts at least partly incorporated into the associated joining plate 4, 4’. In the described embodiment, the anchoring section 5b is provided with a thread.

[0063] Each fastening means 5 thus locally fastens one of the joining plates from arnong the first and the second joining plate 4, 4’ with the other joining plate from arnong the first and the second joining plate 4,4’, while passing through one of the end portions 21, 22 of the conveyor belt 2 interposed between the first and second joining plates 4, 4’ in the joining position. By virtue of a pair of a first type of inserts from among the inserts 6, 7 and of a second type of associated inserts from among the inserts 6, 7 of a given fastening means 5, the fastening can remain locked.

[0064] In this embodiment, the inserts 6 of the first joining plate 4 form a first part ofthe inserts of the first interface. They comprise a perforated washer 61 comprising a cup 62 able to house the head 5a of the fastening means 5. When joining the first and second end portions of the conveyor belt 2 together, each screw 5 is inserted through one of the corresponding holes 47 of the first joining plate 4 until its head 5a is housed m the cup 62 of the washer 61 forming the insert 6. This type of insert is fuily embedded in the body 45 of the joining plate.

[0065] The inserts 7 of the second joining plate 4’ form a second part of the inserts of the second interface. They comprise a cylindrical tubular portion 73, an inner cylindrical surface 74 of which is able to cooperate with the anchoring section 5b of the fastening means 5. In the described embodiment, the inner cylindrical surface 74 comprises a tapping. When joining the first and second end portions of the conveyor belt 2 together, each screw 5 is inserted through one of the corresponding holes 47 of the first joining plate 4 until its head 5a is housed in the cup 62 of the washer 61 forming the insert 6 and, concomitantly, until the threaded anchoring section 5b passes through the corresponding end portion of the conveyor belt 2 and then screws into the tapping 74 of the insert 7. This type of insert is partly embedded in the body 45 of the joining plate, with at least a portion of the cylindrical tubular portion 73 projecting from the inner surface of the associated joining plate.

[0066] In the joining device 1, the through-holes 47 of the joining plate 4 are each coaxial with each pairof associated inserts 6, 7 ofthe first joining plate 4 and of the second joining plate 4’. In the described embodiment, a diameter ofthe through-holes 47 is strictly less than an outer diameter ofthe head 5a ofthe associated fastening element and in this case is strictly less than a diameter of a fastening opening of the associated insert 6, so that the body 45 partly covers the fastening openings of the inserts, while ensuring the passage of the rod of the associated fastening element 5. In particular, in this case, the diameter of the through-holes 47 is equal to the thread root diameter of the thread of the anchoring section 5b of the associated fastening element 5. In this way, the screw can be inserted into the insert 6 after passing through the through-hole 47, by being screwed into the material of the body 45 that partly covers the fastening openings of the inserts 6. In other words, this allows the fastening element 5 to be screwed into the body 45 delimiting the associated hole 47. Thus, the through-holes 47 resiliently deform when the fastening element 5 is introduced, then retum to their initial diameter, at least on the screw head, and fulfil a function of ensuring the passage of the screw by screwing. This also allows screws to be kept prepositioned in the body of the joining plate 4. The outer surface SI actually has a useful surface area that is greater than that of the prior art, where the screw heads corne level with this surface of the conveyor belt. Furthermore, the size ofthe holes 47 reduces the risk ofcracks appearing, which increases the service life ofthe associated joining plate 4. In practice, it also has been noted that the passage ofthe screw does not create prématuré wear of the joining plate.

[0067] This embodiment allows the joining device 1 to be mounted on a conveyor from above, with the least amount of cavities and asperities possible in order to thus limit dégradation due 5 to abrasion. The coating of the junction can wear in the same way as that of the conveyor belt without affecting the fastening éléments and the inserts. With a shorter threaded fastener, better dynamic operation is provided on high-endurance coating belts.

[0068] Figures 4a and 4b illustrate a joining device 1 according to another described embodiment of the invention that basically differs from the previous embodiment in that the 10 inserts 6 of the first upper joining plate 4 form part of the inserts, in this case of the second interface, and in that the body 45 of the first upper joining plate fully, and not only partly, covers the fastening openings of the inserts 6. They comprise a cylindrical tubular portion 63 delimiting the fastening opening and having an inner cylindrical surface 64 that is able to cooperate with the anchoring section 5b of the fastening means. The inserts 7 of the second 15 lower joining plate 4’ form part of the inserts, in this case of the first interface. They comprise a perforated washer 71 comprising a cup 72 delimiting the fastening opening and able to house the head 5a of the fastening means 5. In the described embodiment, the inner cylindrical surface 74 comprises a tapping.

[0069| In this case, the holes 47 are not through-holes and extend from the inner surface S2 of 20 the body 45 into the lower half of the first joining plate 4. In other words, the body 45 that fully covers the fastening openings of the inserts 6. The outer surface SI is thus devoid of any interface that would represent zones conducive to the appearance of structural defects such as cracks.

[0070] This embodiment allows the joining device to be mounted on a conveyor from below, 25 but allows a holeless junction coating to be provided on the face in contact with the materials to be conveyed. This offers an advantage since the coating will be as smooth as the coating of the belt, and therefore less sensitive to abrasion. The coating thickness can vary as a function of the coating thickness of the belt. In this case, the length of the screws is no longer influenced by the thickness of the coating. Shorter screws ensure better dynamic operation.

[0071] Naturally, the invention is described above by way of example. It is understood that a person skilled in the art is able to produce varions alternative embodiments of the invention, yet without departing from the scope of the invention.

[0072] It should be noted that ail the features, as they are set forth for a person skilled in the art 5 from the présent description, the drawings and the attached daims, even if, strictly speaking, they hâve only been described in relation to other determîned features, both individually and in any combinations, can be combined with other features or groups of features disclosed herein, provided that this has not been expressly excluded or that technical circumstances make such combinations impossible or meaningless.

Claims (19)

1. l, A joining plate (4) for a joining device (l) for a conveyor belt (2) intended to connect two end portions (21, 22) of at least one conveyor belt (2), the joining plate (4) having an outer surface (SI) intended to be flush with a useful surface of the conveyor belt (2) in the joining position and an inner surface (S2) opposite the outer surface (SI) and intended to at least partially cover the two end portions (21, 22) ofthe conveyor belt (2) in the joining position, the joining plate comprising:

   - a body (45) made of flexible material, having an outer surface forming the outer surface (SI) ofthe joining plate (4);

   - a reinforcement plate (11) having fastening through-holes, rigidly connected to the body;and

   - a plurality of inserts (6) at least partly embedded in the body (45) and each having a fastening opening associated with one of the fastening holes, so as to surround a rim of the associated fastening hole on one side of the reinforcement plate (11), for accommodating fastening means (5) of the joining device (1) with the end portions (21,22);

   the joining plate (4) being characterized in that the body (45) at least partly covers the fastening openings of the inserts.
2. 2. The joining plate (4) as claimed in the preceding claim, characterized in that the body (45) has a minimum thickness, measured between the outer surface (SI) and the inserts (6), that is greater than or equal to a distance equal to a height of the associated inserts.
3. 3. The joining plate (4) as claimed in claim 1 or 2, characterized in that the joining plate (4) has an outer surface (S 1) formed by an outer surface of the body (45) and an inner surface (S2) opposite the outer surface (SI) and formed by an inner surface of the body (45) and/or of the reinforcement plate ( 11 ), the outer surface (SI) and the inner surface (S2) being équidistant from each other on either side of a middle plane (P) of the joining plate (4), the reinforcement (11) and the inserts (6) being positioned on the inner side of the joining plate relative to the middle plane (P), preferably between the middle plane and the inner surface (S2).
4. 4. The joining plate (4) as claimed in any one of the preceding daims, characterized in that the reinforcement plate (11) is housed in the body (45) and extends at a constant distance from the outer surface (S 1 ).
5. 5. The joining plate (4) as claimed in any one ofthe preceding daims, characterized in that the body (45) is formed from an elastomer material, preferably made of rubber, and has extensibility ranging between 15% and 40%, preferably between 20% and 30%.
6. 6. Thejoining plate (4) as claimed in any one of the preceding daims, characterized in that the body (45) of the joining plate (4) comprises holes (47) extending from the inner surface (S2) of the body (45) in the lower half of the joining plate (4), the holes (47) being configured to partly house the fastening means (5).
7. 7. The joining plate (4) as claimed in any one ofthe preceding daims, characterized in that the body (45) comprises through-holes (47), extending from the outer surface (SI) of the body (45) of the joining plate (4) toward the inner surface (S2), the holes (47) being configured to be each traversed by one of the fastening means (5).
8. 8. The joining plate (4) as claimed in the preceding claim, characterized in that each ofthe through-holes (47) is coaxial with one of the fastening openings of one of the associated inserts (6) of the joining plate (4).
9. 9. A joining device (l) for a conveyor belt (2) intended to connect two end portions (21, 22) of at least one conveyor belt (2), characterized in that it comprises at least one joining plate (4) as claimed in any one of the preceding daims.
10. 10. The joining device (l ) for a conveyor belt (2) as claimed in the preceding claim, characterized in that it comprises a first joining plate (4) as claimed in any of daims l to 8 and a second plate (4’) comprising a plurality of inserts (7), the two plates (4, 4’) being configured to each cover a separate side of the ends of the conveyor belt (2) so that said conveyor belt (2) is disposed between the two joining plates in the joining position, the first and second joining plates (4, 4’) being fastened together by fastening means (5) arranged to at least partly respectively penetrate a joining plate from among the first and the second joining plate (4, 4’), one of the end portions (21, 22) of the conveyor belt (2) and then the other joining plate from among the first and the second joining plate (4,4’).
11. 11. The joining device (l) as claimed in the preceding claim, characterized in that a thickness (E) of the first joining plate (4) is greater than or equal to, preferably strictly greater than, a thickness of the second joining plate (4’) of the joining device (l), preferably greater than or equal to twice the thickness of the second joining plate (4’), more preferably greater than or equal to three times the thickness of the second joining plate (4’)·
12. 12. The joining device (l) for a conveyor belt (2) as claimed in the preceding claim, characterized in that the fastening means (5) comprise rod fastening means, preferably of the screw type, the fastening means each preferably comprising a head (5a) configured to cooperate with a portion of the inserts (6, 7) and an anchoring section (5b), preferably provided with a thread, configured to cooperate with another portion of the inserts (6, 7).
13. 13. The joining device (l) for a conveyor belt (2) as claimed in the preceding claim, characterized in that the inserts (6, 7) configured to cooperate with a head (5a) of the fastening means (5) each comprise a washer (61, 71) perforated by the associated fastening opening surrounded by a cup (62, 72) able to house the head (5a) of the fastening means (5), and the inserts (6, 7) configured to cooperate with an anchoring section (5b) of the fastening means (5) each comprise a cylindrical tubular portion (63, 73) delimiting the associated fastening opening for which an inner cylindrical surface (64, 74) is able to cooperate with the anchoring section (5b) of the fastening means (5), the inner cylindrical surface (64, 74) preferably comprising a tapping.
14. 14. The joining device (l) as claimed in the preceding claim, characterized in that the first joining plate (4) only comprises tapped inserts (6) configured to cooperate with the threaded anchoring sections (5b) of the fastening means (5),
15. 15. Thejoining device (1) as claimed in claim 13, characterized in that the first joining plate (4) only comprises inserts (6) configured to cooperate with the heads (5a) of the fastening means (5).
16. 16. Thejoining device (1) as claimed in any one ofdaims 10 to 15, with the firstjoining plate (4) being a joining plate as claimed in claim 7 or 8, characterized in that the through-holes (47) are each coaxial with the fastening openings of each associated pair of inserts (6, 7) of the firstjoining plate (4) and of the second joining plate (4’), in thejoining position.
17. 17. Thejoining device (1) as claimed in any one of daims 10 to 13 and 15, including claim 13, with the first joining plate (4) being a joining plate as claimed in claim 7 or 8, characterized in that a diameter of the through-holes (47) is strictly smaller than a diameter of the fastening opening of the associated insert (6), preferably strictly less than an outer diameter of the head (5a) of the associated fastening element (5), preferably strictly less than a nominal diameter of the anchoring section (5b) ofthe associated fastening element (5), more preferably substantially equal to the thread root diameter of the thread of the anchoring section (5b) of the associated fastening element (5).
18. 18. A method for manufacturing a joining plate (4) as claimed in any one of daims 1 to 8, characterized in that it comprises at least the following steps of:

    - manufacturing a continuons sériés of a plurality of joining plates (4) in strip form; and - cutting, from said strip thus manufactured, joining plates (4) according to predetermined dimensions.
19. 19. A method for joining a first end portion and a second end portion of a conveyor belt (2) using a joining device (1) for a conveyor belt (2) as claimed in any one of daims 9 to 18, comprising a first joining plate (4) as claimed in any one of daims l to 8 and a second joining plate (4’), characterized in that it comprises at least:

    - a step involving the first joining plate (4) and the second joining plate (4’) each covering a separate side of the end portions (21, 22) of the conveyor belt (2) so that said 5 conveyor belt is vertically interposed between the two joining plates (4, 4’), said first and second joining plates (4, 4’) forming a first pair of wings (40) that is adapted to clamp the first end portion (21) of the conveyor belt (2) and a second pair of wings (42) that is adapted to clamp the second end portion (22) of the conveyor belt (2);

    - a step of inserting the second end of the conveyor belt (2) between two wings of the 10 second pair of wings (42);

    - a step of fastening the second end portion (22) of the conveyor belt (2) with the two wings of the second pair of wings (42) between which it is positioned;

    - a step of inserting the first end portion (21 ) of the conveyor belt (2) between the two wings of the first pair of wings (40);

    15 - a step of fastening the first end portion (21 ) of the conveyor belt (2) with the two wings of the first pair of wings (40) between which it is positioned.