Field of the invention

The present invention relates to a chain plate configured to absorb shock forces in a straight side plate conveyor chain, a straight side plate conveyor chain and also a conveyor system comprising such conveyor chain.

Background of the invention

A typical conveyor chain comprises a plurality of first type links, also known as roller links, that are connected by a plurality of second type links, also known as pin links. Each first type link comprises a pair of inner chain plates that are interconnected by two tubular bushings. Two subsequent first type links in the conveyor chain are interconnected by a second type link. Each second type link comprises a pair of outer chain plates and two pins. A first of the two pins is configured to be inserted into a respective bushing of a first of the two subsequent first type links, and a second of the two pins is configured to be inserted into a respective bushing of a second of the two subsequent first type links.

A conveyor chain is typically during its normal operation in a machine, such as a conveyor system or the like, subjected to very high loads. The conveyor chain will every now and then during its normal operation be subjected to what is referred to as shock loads which is best described as a very sudden peak load that lasts for a very short period of time. A shock load typically occurs during normal operation when a load is arranged on the conveyor system in which the conveyor chain is used, during start of the conveyor system, or during a breakdown.

During a shock load, a load concentration will be formed in the interface between the pins and their respective bushings and especially in the area in and around the interface between the inner chain plate and the outer chain plate. When a conveyor chain is subjected to a load that exceeds the value of the dimensioned bearing force between the pin and the bushing, there is a risk that the material is plastically deformed and that the conveyor chain is damaged. Also, over time, the conveyor chain will become longer. In the event the shear load, i.e. , the load between the outer chain plate and a pin is too high, a pin or a tubular bushing may rupture and the conveyor chain will burst. In the event the tension becomes too high, any of the chain plates may rupture. A burst results in an immediate and severe breakdown of the complete conveyor system. Not only is there a risk for personal injuries but also costly damages to the machinery.

There is hence a need for a new type of conveyor chain that is designed to better withstand normal wear. Especially, there is a need for a new type of conveyor chain providing an improved ability to accommodate inevitable shock loads to thereby prolong the overall life length of a conveyor chain.

Summary of the invention

It is an object of the present invention to solve, or at least mitigate, parts or all of the above-mentioned problems.

Especially, it is an object of the invention to provide an improved chain plate configured to allow accommodation of dynamic shock forces in a straight side plate conveyor chain.

Another object is to provide an improved chain plate that allows the energy in the shock load to be accommodated by distributing the load over a longer period of time and also by reducing its magnitude.

Yet another object is to provide a new type of conveyor chain that is configured to absorb shock forces and thereby exhibit an enhanced useful life length.

To this end, there is provided a chain plate configured to absorb shock forces in a straight side plate conveyor chain, the chain plate comprising: a first connection portion configured to directly or indirectly connect to a first pin of the conveyor chain at a first pin connection point; a second connection portion configured to connect to a second pin of the conveyor chain at a second pin connection point; and two legs extending side by side between the first and the second connection portions, said two legs having a non-linear extension; wherein each of the two legs has a first length as seen in an unloaded condition and as measured along said non-linear extension between the first and second pin connection points respectively, the first length being longer than a length of a straight centerline extending between the first and second pin connection points; whereby when a conveyor chain comprising such chain plate is subjected to a shock load, the legs are elastically, at least partly straightened, whereby a distance between the first and second pin connection points respectively is resiliently increased as compared to the distance between the first and second pin connection points respectively in the unloaded condition; and, wherein each leg comprises at least one slit extending in a thickness direction of the chain plate and extending at least partly along the extension of the respective leg, thereby dividing each leg into two or more lamellas.

The two or more lamellas may have the same width or have different widths as seen in a direction transverse to the thickness direction of the chain plate. The at least one slit is preferably a through-going slit.

Accordingly, a chain plate is provided that comprises two connection portions that are interconnected by two legs. The chain plate of the present invention is applicable in a conveyor chain no matter if it is intended to be used as an inner chain plate or an outer chain plate.

Depending on if the chain plate is an inner chain plate or an outer chain plate, the first and second connection portions will either directly or indirectly connect to a pin when two chain plates form a chain link. In the event of the chain plates are inner chain plates configured to form a first type (inner) chain link, pins supported by a pair of outer chain plates configured to form a second type (outer) chain link, are configured to extend though respective tubular bushings to be supported by the pair of inner chain plates. This should in the context of the present application be understood as a "indirect connection" between a connection portion and a pin. Correspondingly, in the event the chain plate instead is an outer chain plate, the two pins will connect directly to the first and second connection portions of the outer chain plates when these form a second type (outer) chain link.

Each leg has a non-linear extension. Each of the two legs has, as a result of its non-linear extension, a first length as measured along said non-linear extension between the first and second pin connection points, which is longer than a length of a straight centerline that extends between the first and second pin connection points. In the context of the application, the term "pin connection point’ is to be understood as the center of a pin to be directly or indirectly connected to the respective connection portion of the chain plate.

The straight-linear distance as measured between the first and second pin connection points of a chain is often referred to in the art as the pitch. Hence, and in other words, the chain plate of the invention is provided with two legs that each has a length that exceeds the pitch of the conveyor chain in which it is intended to be used. This “overlength” allows, in a condition when the conveyor chain is subjected to a shock load, the legs to be elastically, at least partly straightened, whereby a distance between the first and second pin connection points is resiliently increased as compared to the distance between the first and second pin connection points in the unloaded condition. Thereby a dynamic accommodation of the shock load is provided for where the energy in the shock load is allowed to be distributed over a longer period of time and also with an overall reduced magnitude. This in return reduces the stress in the interface between the pins and their respective bushings. Thus, there is a reduced risk of the pin and/or bushing getting sheared. It also reduces the risk of a chain plate rupture.

In the context of the present invention the term “non-linear extension" should, unless nothing else is explicitly given, be understood as an extension having a curvature or another non-straight extension. The curvature may be single-curved or have two or more curved portions. Further, the non-linear extension may be provided as two or more linear sub-sections being interconnected via curved or angular bridging portions.

The skilled person realizes that the number of legs in the chain plate may be two or more.

The skilled person also realizes that not all chain plates in a conveyor chain must be chain plates of the type as prescribed by the invention. It is however preferred that chain links using such chain plates are evenly distributed along the full length of a conveyor chain, such as in every second, every third or every fourth chain link. The frequency can be adapted to the expected load conditions of a specific installation.

By providing each leg with at least one slit that extends in the thickness direction of the chain plate and that extends at least partly along the extension of the respective leg, each leg is divided into two or more lamellas. By slitting each leg to form two or more lamellas, the elasticity of the legs is improved while maintaining the same amount of material. The improved elasticity will allow an improved ability to resist/accommodate shock loads. The lamellas will act as a leaf spring where each lamella constitutes a leaf.

A bending strength of the two legs, as measured in a virtual plane extending in parallel with an elongated extension of the chain plate may be smaller than a tensile strength of the two legs as seen across a respective minimum cross-sectional area of the two legs. Thereby, the legs will as a first stage when subjected to load be allowed to elastically deform by bending rather than being axially stretched to thereby accommodate the energy in the shock load.

The bending strength of the two legs may be 1-25 % smaller than the tensile strength of the two legs. More preferred, the bending strength of the two legs may be 5-10% lower than the tensile strength of the two legs.

The two legs may be mirror symmetrical as seen about the straight centreline of the chain plate. By a mirror symmetry the chain plate will exhibit the same properties no matter where in a conveyor chain the chain plate is momentarily positioned during operation of the conveyor chain.

The two legs may each have a convex curvature in view of the straight centreline of the chain plate. Alternatively, the two legs may each have a concave curvature in view of the straight centreline of the chain plate. The skilled person realizes that each of the two legs alternatively may have a combination of convex and concave portions.

In the event the chain plate is an outer chain plate, the first connection portion of such outer chain plate may comprise a through-going opening configured to receive a first pin, and the second connection portion of such outer chain plate may comprise a through-going opening configured to receive a second pin. The thus protruding ends of the first and second pins may be configured to be fixed to a surface of the outer chain plate by e.g., welding, riveting or press fit. Alternatively, the protruding ends of the first and second pins may be configured to be releasably mounted to an outer surface of the outer chain plate, e.g., by means of a removable screw or a removable locking pin. A releasable engagement between the pins and the outer chain plate allows the provision of an outer chain link that is openable, also known in the art as a splice link.

In another embodiment, the first connection portion of the outer chain plate may fixedly support a first pin, and the second connection portion of the outer chain plate may fixedly support a second pin. The first and second connection portions may accordingly be provided as generally flat surfaces configured to fixedly receive an abutting end of the respective pins by means of e.g., welding. In such embodiment, the pin will be fixed to an inner surface of the outer chain plate. This may by way of example be made by friction welding.

The skilled person realizes that when arranging an outer chain plate of the present invention in an outer chain link, one of the two opposing outer chain plates may be provided with generally continuous, i.e. , non-broken, first and second connection portions whereas the other of the two opposing outer chain plates may be provided with first and second connection portions having through-going openings which openings are configured to receive a respective pin.

The at least one slit in each of the two legs of the chain plate may be formed by laser cutting or by water cutting. Also, the opening between the two legs may be formed by laser cutting or by water cutting. By using laser or water cutting the risk of initiating cracks in the material will be substantially reduced. Thereby the overall life length of the resulting chain plate may be improved. This is of importance since the chain plate will be subjected to a cyclic load during use. It should be stressed that these technical effects are equally applicable to an inner chain plate.

The at least one slit in each of the two legs of the chain plate may be formed by a method different than a method used for forming an outer contour of the chain plate. Also, the opening between the two legs may be formed by a method different than the method used for forming the outer contour of the chain plate. While the overall contours of a chain plate typically for sake of efficiency is formed by punching, the opening between the legs and the at least one slit may be formed by laser or water cutting.

According to another aspect, a straight side plate conveyor chain configured to absorb shock forces is provided. The conveyor chain may comprise a plurality of first type links, each first type link comprising a pair of inner chain plates interconnected by two tubular bushings, and wherein two subsequent first type links in the conveyor chain are interconnected by a second type link, each second type link comprising a pair of outer chain plates and two pins, wherein a first pin of the two pins is inserted into a respective tubular bushing of a first of the two subsequent first type links, and a second pin of the two pins is inserted into a respective tubular bushing of a second of the two subsequent first type links; and wherein the pair of inner chain plates in at least one of the plurality of first type links; and/or the pair of outer chain plates in at least one of the plurality of second type links are chain plates according to any of claim 1-8.

Accordingly, a straight side plate conveyor chain configured to absorb shock forces is provided which as one integral part thereof comprises chain plates of the type that has been described and discussed above. The features, properties and advantages provided by such chain plates have been thoroughly discussed above and those arguments are equally applicable to a conveyor chain comprising such chain plates. Therefore, reference is made to the sections above to avoid undue repetition. A total cross-sectional area of the two legs of an outer chain plate as seen in a position along the longitudinal extension of the two legs where the total cross sectional area is the smallest, may in one embodiment be equal to or exceed a total cross sectional area of an inner chain plate with which the outer chain plate is configured to cooperate, as seen in a position along a longitudinal extension of the inner chain plate where the total cross sectional area is the smallest. This is preferably the case in the event the outer chain plates and the inner chain plates of a conveyor chain are made of the same material and are subjected to one and the same thermal treatment. Thereby, the outer chain plate will exhibit at least the same tensile strength as an inner chain plate when being arranged in a conveyor chain. Correspondingly, or alternatively, a total cross-sectional area of the two legs of an inner chain plate as seen in a position along the longitudinal extension of the two legs where the total cross-sectional area is the smallest, may be equal to or exceed a total cross-sectional area of an outer chain plate with which the inner chain plate is configured to cooperate, as seen in a position along a longitudinal extension of the inner chain plate where the total cross-sectional area is the smallest.

The tensile strength of a chain plate, as seen in a position along the longitudinal extension of the two legs of an outer chain plate where the total cross- sectional area is the smallest, may in one embodiment equal to or exceed the lowest tensile strength in one of an inner chain plate, a tubular bushing or a pin with which the outer chain plate is configured to cooperate with when forming a conveyor chain. Accordingly, it is preferred that the tensile strength of the outer chain plate should not be lower than the tensile strength of the other components of the conveyor chain. This may be seen as a dimensioning parameter that may be of importance when selecting material and type of thermal treatments since the different parts in a conveyor chain may be made of different materials and/or be subjected to different heat treatments.

Correspondingly, or alternatively, the tensile strength of an inner chain plate, as seen in a position along the longitudinal extension of the two legs where the total cross-sectional area is the smallest, may equal to or exceed the lowest tensile strength in one of an outer chain plate, a tubular bushing or a pin with which the inner chain plate is configured to cooperate with when forming a conveyor chain.

According to yet another aspect, a straight side plate conveyor chain configured to absorb shock forces is provided. The conveyor chain comprises a plurality of first type links, each first type link comprising a pair of inner chain plates interconnected by two tubular bushings, and wherein two subsequent first type links in the conveyor chain are interconnected by a second type link, each second type link comprising a pair of outer chain plates and two pins, wherein a first of the two pins is inserted into a respective tubular bushing of a first of the two subsequent first type links, and a second of the two pins is inserted into a respective tubular bushing of a second of the two subsequent first type links; and wherein each outer chain plate of at least one second type link comprises: a first connection portion configured to connect to the first of the two pins at a first pin connection point; a second connection portion configured to connect to the second of the two pins at a second pin connection point; and two legs having a non-linear extension and extending side by side between the first and the second connection portions, each of the two legs has a first length as seen in an unloaded condition and as measured along said non-linear extension between the first and second pin connection points respectively, the first length being longer than a length of a straight centerline extending between the first and the second pin connection points, whereby, when the conveyor chain is subjected to a shock load, the legs are elastically at least partly straightened, whereby a distance between the first and second pin connection points is resiliently increased as compared to the distance between the first and second pin connection points in the unloaded condition, and wherein each leg comprises at least one slit extending in a thickness direction of the chain plate and extending at least partly along the extension of the respective leg, thereby dividing each leg into two or more lamellas.

Accordingly, a straight side plate conveyor chain configured to absorb shock forces is provided which as one integral part thereof comprises an outer chain plate of the type that has been described and discussed above. The features, properties and advantages provided by such outer chain plate have been thoroughly discussed above and those arguments are equally applicable to a conveyor chain comprising such outer chain plate. Therefore, reference is made to the sections above to avoid undue repetition.

The conveyor chain may comprise a combination of second type links having outer chain plates according to the present invention and second type links having outer chain plates according to prior art.

A bending strength of the two legs as measured in a virtual plane extending transverse to a longitudinal extension of the first and second pins, may be smaller than a tensile strength of the two legs as seen across a minimum cross- sectional area of the two legs.

A tensile strength of the outer chain plate, as seen in a position along the longitudinal extension of the two legs where the total cross-sectional area is the smallest, may equal or exceed the lowest tensile strength in one of an inner chain plate, a tubular bushing or a pin with which the outer chain plate is configured to cooperate with when forming a conveyor chain. Accordingly, it is preferred that the tensile strength of the outer chain plate should not be lower than the tensile strength of the rest of the conveyor chain. This may be seen as a dimensioning parameter that may be of importance when selecting material and type of thermal treatments since the different parts in a conveyor chain may be made of different materials and/or be subjected to different heat treatments. The first and second connection portions of at least one of the chain plates in a pair of outer chain plates of the type describe above may in one embodiment each comprise a through-going opening configured to receive a first and a second pin respectively.

The skilled person realizes that when applying the chain plate of the present invention in an outer chain link, one of the two opposing outer chain plates may be provided with generally continuous, i.e. , non-broken first and second connection portions whereas the other of the two opposing outer chain plates may be provided with first and second connection portions having through-going openings.

The first connection portion may comprise a through-going opening configured to receive a first pin, and the second connection portion may comprise a through-going opening configured to receive a second pin. The thus protruding ends of the first and second pins may be configured to be fixed to the outer chain plate by e.g., welding, riveting or press fit. Alternatively, the protruding ends of the first and second pins may be configured to be releasably mounted to the outer chain plate, e.g., by means of a removable screw or a removable locking pin. A releasable engagement between the pins and the outer chain plate allows the provision of an outer chain link that is openable, also known in the art as a splice link.

In another embodiment, the first connection portion may fixedly support a first pin, and the second connection portion may fixedly support a second pin. The first and second connection portions may accordingly be provided as generally continuous surfaces configured to fixedly receive an abutting end of a pin by means of e.g., welding. In such embodiment, the pin will be fixed to an inner surface of the outer chain plate.

According to yet another aspect, a conveyor system is provided that comprises a conveyor chain according to any of claims 9-12.

The skilled person also realizes that not all chain plates in a conveyor chain must be chain plates of the type as prescribed by the invention. It is however preferred that chain links using such chain plates are evenly distributed along the full length of a conveyor chains, such as in every second, every third or every fourth chain link etc. The frequency can be adapted to the expected load conditions of a specific installation.

Brief description of the drawings

The above, as well as additional objects, features and advantages of the present invention, will be better understood through the following illustrative and non- limiting detailed description of preferred embodiments of the present invention, with reference to the appended drawings, where the same reference numerals will be used for similar elements, wherein:

Fig. 1 is a schematic exploded view of a portion of a conveyor chain according to one embodiment of the invention with its components.

Fig. 2 is a schematic portion of a conveyor chain according to the invention with its components in an assembled condition.

Fig. 3 discloses one embodiment of a chain plate according to the invention.

Fig. 4 is a graph illustrating force versus time.

Fig. 5 discloses one embodiment of a chain plate according to the invention.

Fig. 6 discloses one embodiment of a chain plate according to the invention.

Fig. 7 discloses one embodiment of a chain plate according to the invention.

Fig. 8 discloses one embodiment of a chain plate according to the invention.

Fig. 9 is a schematic cross section of outer chain plate according to the first embodiment and an inner chain plate of ordinary type.

Fig. 10 schematically discloses one way of assembling a second type chain link.

Fig. 11 schematically discloses an alternative way of assembling a second type chain link.

Fig. 12 is a schematic portion of an alternative conveyor chain according to the invention with its components in an assembled condition with inner chain plates according to the invention.

Fig. 13 is a schematic portion of an alternative conveyor chain according to the invention with its components in an assembled condition with both inner chain plates and outer chain plates according to the invention.

Detailed description of the exemplary embodiments

Turning to Figs. 1 and 2, a portion of one embodiment of a conveyor chain 1000 according to the invention is provided. The conveyor chain 1000 is of the type also known as a straight side plate conveyor chain. While Fig. 1 is a partially exploded view, Fig. 2 discloses the same chain portion in an assembled condition. For the sake of facilitated understanding of the overall design, the at least one slit in each leg is omitted in Figs. 1 and 2.

The portion of the conveyor chain 1000 comprises two first type links 100 which are interconnected by two second type links 200 to thereby form a conveyor chain of a desired length. Each first type link 100, also known in the art as a roller link, comprises a pair of inner chain plates 10T according to prior art that are interconnected by two tubular bushings 102. The two opposing ends of the bushings 102 are typically fixedly connected to a respective inner chain plate 10T. The two tubular bushings 102 may in some embodiments of the conveyor chain 1000 support a roller bearing (not illustrated) that circumferentially encircles the outer envelope surface of the respective bushing 102.

Two subsequent first type links 100 in the conveyor chain 1000 are interconnected by a second type link 200, also known in the art as a pin link. Each second type link 200 comprises a pair of outer chain plates 201 and two pins 202A, 202B. The two outer chain plates 201 are examples of chain plates of the type according to the invention. A first 202A of the two pins is inserted into a respective bushing 102 of a first of the two subsequent first type links 100’, and a second 202B of the two pins is inserted into a respective tubular bushing 102 of a second of the two subsequent first type links 100’. The conveyor chain 1000 disclosed in Fig. 1 differs from a prior art conveyor chain in the design of the two outer chain plates 201. These outer chain plates 201 will be discussed below. As will be discussed below with reference to Figs. 12 and 13 respectively, the inner chain plates 101 of the conveyor chain 1000 may be chain plates of the type according to the invention. Also, both the inner and outer chain plates 101 , 201 may be chain plates of the type according to the invention,

It is to be stressed that not all chain links in a conveyor chain must be formed by chain plates 101, 201 according to the invention. Rather, the conveyor chain 1000 may comprise a combination of second type links 200 having outer chain plates 201 according to the present invention and second type links having outer chain plates according to prior art with a uniform cross section. Correspondingly, the conveyor chain 1000 may comprise a combination of first type links 100 having inner chain plates 101 according to the present invention and first type links having outer chain plates 10T according to prior art with a uniform cross section.

The number of links 100, 200 with chain plates 101 , 201 according to the invention may vary depending on the total length of the conveyor chain 1000 and also the expected loads during its operation. Further, not all chain plates in a conveyor chain 1000 must be chain plates of the type as prescribed by the invention. It is however preferred that chain links 100, 200 using such chain plates 101, 201 are evenly distributed along the full length of a conveyor chain, such as in every second, every third, every fourth chain link etc. The frequency can be adapted to the expected load conditions of a specific installation. Now turning to Fig. 3, one embodiment of the chain plate 101 ; 201 according to the invention is disclosed. The chain plate can be used either as an inner chain plate 101 , or as an outer chain plate 201. For the sake of facilitated understanding of the overall design of the chain plate, the at least one slit in each leg is omitted in Fig. 3.

The chain plate 101; 201 comprises a first connection portion 103A; 203A, a second connection portion 103B; 203B and two legs 104; 204 that extend side by side between the first and the second connection portions 103A, 103B; 203A, 203B.

The first connection portion103A; 203A is configured to directly or indirectly connect to a first pin 202A of the conveyor chain at a first pin connection point CP1. Correspondingly, the second connection portion 103B; 203B is configured to directly, or indirectly connect to a second pin 202B of the conveyor chain at a second pin connection point CP2. In the context of the application, the term "pin connection point’ is to be understood as the center of a pin to be connected to the respective connection portion 203A, 203B of the outer chain plate.

The first and the second connection portions 103A, 103B; 203A, 203B do in the disclosed embodiment comprise through-going opening 114; 214 configured to receive a respective pin 202A, 202B.

The two legs 104; 204 do each have a non-linear extension. In the context of the present invention the term “non-linear extension" should, unless nothing else is explicitly given, be understood as an extension having a curvature or another nonstraight extension. The curvature may be single-curved or have two or more curved portions. Further, the non-linear extension may be provided as two or more linear sub-sections being interconnected via curved or angular bridging portions.

The two legs 104; 204 are disclosed as having a convex curvature in view of the straight centreline CL of the chain plate 101 ; 201 , which centerline CL extends through the first and second pin connection points CP1, CP2.

An opening 105; 205 in the waist portion of the chain plate 101 ; 201 separating the two legs 104; 204 is provided with two opposing ends 106A, 106B; 206A, 206B adjacent the first and second connection portions 103A, 103B; 203A, 203B of the chain plate 101; 201. The opposing ends 106A, 106B; 206A, 206B merge by a radius.

The two legs 104;204 are preferably mirror symmetrical as seen about the centreline CL of the chain plate 101; 201.

Each of the two legs 104; 204 has a first length L1 as seen in an unloaded condition and as measured along said non-linear extension between the first and second pin connection points CP1, CP2 respectively. The first length L1 is greater than a length L2 of the centerline as measured between the first and second pin connection points CP1, CP2.

The straight-linear distance as measured between the first and second pin connection points CP1, CP2 of a chain is often referred to in the art as the pitch. Hence, the chain plate 101 ; 201 of the invention is provided with two legs 104; 204 that each has a length L1 that exceeds the pitch of the conveyor chain in which it is intended to be used. This “overlength” allows, in a condition when the conveyor chain is subjected to a shock load, the legs 104; 204 to be elastically, at least partly straightened, whereby the distance between the first and second pin connection points CP1, CP2 of the chain plate 101; 201 is resiliently increased as compared to the distance between the first and second pin connection points CP1, CP2 in the unloaded condition. Thereby a dynamic accommodation of a shock load is provided for where the energy in the shock load is allowed to be distributed over a longer period of time and also with an overall reduced magnitude. This is best illustrated in Fig. 4 being a graph plotting the applied force over time. The solid line in the graph refers to a conveyor chain using outer chain plates according to prior art with a uniform cross-sectional profile of the waist portion, i.e. , the portion connecting the first and second connection portions. The dashed line refers to a corresponding conveyor chain of the invention where outer chain plates are replaced by chain plates 201 of the type disclosed in Fig. 3 with two non-linear legs 204 interconnecting the first and second connection portions 203A, 203B. As can be clearly seen from the graph, the use of outer chain plates 201 according to the invention distributes the shock load over a longer period of time while also lowering the magnitude. Simulations do also show that this has the effect that the stress in an interface, see point P in Fig. 2, between the pins and their respective bushings of a conveyor chain 1000 using such outer chain plates 201 may be reduced. Corresponding results are provided for an inner link using inner plate according to the invention.

The chain plate 101; 201 according to the invention may be made of a metallic material such as steel. The metallic material may be subjected to a thermal treatment to improve its strength properties. Alternatively, it may be made of a composite material. The chain plate 101; 201 according to the invention may be made of a material different from the material in the other components making up the conveyor chain.

Now turning to Fig. 5, one embodiment of the outer chain plate 201 according to the invention is disclosed. The principle is equally applicable to a first type chain plate 101 , but to facilitate understanding, the chain plate will be described in the context of an outer chain plate 201. This embodiment differs from the chain plate of Figs. 1 and 2 in that the two legs 204 have a concave curvature in view of the straight centreline CL of the outer chain plate 201 that extends between the first and second connection points CP1, CP2.

Each leg 204 comprises a plurality of slits 206 that extend in a thickness direction of the outer chain plate 201 and that extend at least partly along the extension of the respective leg 204. Each leg 204 is thereby divided into a plurality of lamellas 207. The plurality of lamellas 207 are each disclosed as having the same width as seen in a direction transverse to the thickness direction of the outer chain plate 201. The skilled person realizes that the lamellas 207 with remained function may have different widths.

The number of slits 206 in each leg 204 may be one or more, whereby the number of lamellas 207 in each leg 204 may be two or more. Also, the at least one slit 206 is preferably a through-going slit. The one or more slits 206 do preferably have an extension corresponding to the non-linear extension of the respective leg 204.

By slitting each leg 204 to form two or more lamellas 207, the elasticity of the legs 204 is improved while maintaining the same amount of material. The improved elasticity will allow an improved ability to resist/accommodate shock loads. The lamellas 207 will act as a leaf spring where each lamella constitutes a leaf.

The at least one slit 206 in each of the two legs 206 of the chain plate may be formed by laser cutting or by water cutting. Also, the opening 205 between the two legs 206 may be formed by laser cutting or by water cutting. By using laser or water cutting the risk of initiating cracks in the material will be substantially reduced. Thereby the overall life length of the resulting chain plate may be improved. This is of importance since the chain plate will be subjected to a cyclic load during use. It should be stressed that these technical effects are equally applicable to an inner chain plate.

The at least one slit 206 in each of the two legs 204 may be formed by a method different than a method used for forming an outer contour of the chain plate. Also, the opening 205 between the two legs 204 may be formed by a method different than the method used for forming the outer contour of the chain plate. While the overall contours of a chain plate typically for sake of efficiency is formed by punching, the opening between the legs 204 and the at least one slit 206 may be formed by laser or water cutting.

Now turning to Fig. 6, another embodiment of the outer chain plate 201 is disclosed. The principle is equally applicable to a first type chain plate 101 , but to facilitate understanding, the chain plate will be described in the context of an outer chain plate 201. The two legs 204 have a concave curvature in view of the straight centreline CL of the outer chain plate 201 that extends between the first and second pin connection points CP1, CP2. Further, each leg 204 has a single slit 206. Each slit 206 is outwardly displaced X in view of a longitudinal centerline L1 of the respective leg 206. Further, the ends of the respective slit 206 merge with a radius 208 equal to or exceeding the width of the slit 206. Each leg 204 is thereby divided into two lamellas 207 having different widths.

The opening in the waist portion of the chain plate 201 separating the two legs 204 is provided with two opposing ends adjacent the first and second connection portions 203A, 203B. The opposing ends are provided with an acute angle a.

Now turning to Fig. 7, yet another embodiment of the outer chain plate 201 is disclosed. The principle is equally applicable to a first type chain plate 101 , but to facilitate understanding, the chain plate will be described in the context of an outer chain plate 201. The two legs 204 have a non-linear extension which as such is formed by three linear sub-sections 213 where two adjacent sub-sections 213 meet at an angle p in a bridging portion 209. To improve the flexibility, each bridging portion 209 along the two legs 204, and where the respective leg 204 meet the first and second connection portions 203A, 203B are provided with an optional cut-out 210 having a radius.

For the sake of facilitated illustration, the slits in the legs have been omitted, whereby the two legs 204 are disclosed as having a uniform cross section. The nonillustrated slits in the two legs 204 divide each leg into two or more lamellas.

Now turning to Fig. 8, yet another embodiment of the outer chain plate 201 is disclosed. The principle is equally applicable to a first type chain plate 101 , but to facilitate understanding, the chain plate will be described in the context of an outer chain plate 201. The two legs 204 have a non-linear extension which as such has a wave-like extension with valleys 211 and ridges 212. The ridges 212 along the outer edge of each leg 204 are preferably arranged along a straight line L3.

For the sake of facilitated illustration, the slits in the two legs have been omitted, whereby the two legs 204 are disclosed as having a uniform cross section. The non-illustrated slits divide each leg into two or more lamellas.

As is realized, at least from the different embodiments discussed above, the outer chain plate according to the invention may be provided with legs having different non-linear extensions to better allow absorption of shock loads when the outer chain plates are used in a conveyor chain. Now turning to Fig. 1. To facilitate the shock absorption by a resilient, i.e., elastic deformation of the legs 204, it is preferred that a bending strength of the two legs 204, as measured in a virtual plane VP extending in parallel with an elongated extension of the chain plate, is smaller than a tensile strength of the two legs 204 as seen across a respective minimum cross-sectional area of the two legs 204. The bending strength of the two legs 204 may be 1-25 % lower than the tensile strength of the two legs 204. More preferred, the bending strength of the two legs may be 5- 10% lower than the tensile strength of the two legs 204.

Now turning to Fig. 9. For the sake of facilitated illustration, the slits in the legs have been omitted. From a strength perspective, it is preferred that a total cross-sectional area A (A=the sum of the cross sectional areas A1+A2) of each leg 204) of the two legs as seen in a position along the longitudinal extension of the two legs 204 where the total cross sectional area is the smallest, may be equal to or exceed a total cross sectional area B (B=the sum of the cross sectional areas B1+B2 of an inner chain plate 101 with which the outer chain plate 201 is configured to cooperate, as seen in a position along a longitudinal extension of the inner chain plate 101 where the total cross sectional area is the smallest, i.e. across the through- going holes. This is preferably the case in the event the outer chain plates 201 and the inner chain plates 101 of a conveyor chain are made of the same material and are subjected to one and the same thermal treatment. Thereby, the outer chain plate 201 will exhibit at least the same tensile strength as an inner chain plate 101.

However, in many cases, the different components making up the conveyor chain are not made by the same material and are also not subjected to the same kind of heat treatment, whereby the choice of material in the different components must be considered when dimensioning the conveyor chain and especially the outer chain plates 201.

In such circumstances, the tensile strength of the outer chain plate 201 , as seen in a position along the longitudinal extension of the two legs 204 where the total cross-sectional area A (A=the sum of the cross sectional areas A1+A2) is the smallest, may equal to or exceed the lowest tensile strength in one of an inner chain plate 101, a tubular bushing 102 or a pin 202A, 202B with which the outer chain plate 201 is configured to cooperate with when forming a conveyor chain. It is preferred that the tensile strength of the chain plate 101, 201 according to the invention, no matter if it is an inner chain plate or an outer chain plate, should not be lower than the tensile strength of the rest of the conveyor chain. This may be seen as a dimensioning parameter that may be of importance when selecting material and type of thermal treatments since the different parts in a conveyor chain may be made of different materials and/or be subjected to different heat treatments.

Now turning to Fig. 10, a schematic side view of two outer chain plates 201 according to the invention is disclosed. The two chain plates 201 are configured to form a chain link of the second type 200, i.e., a pin link.

The two pins 202A, 202B may be fixedly supported by the first and second chain plate 201 in a number of ways. The first connection portion 203A in each chain plate 201 may comprise a through-going opening 214 configured to receive the first pin 202A, and the second connection portion 203B may comprise a through-going opening 214 configured to receive the second pin 202B. The thus protruding ends of the first and second pins 202A, 202B may be configured to be fixed to the respective chain plate 201 by e.g., welding, riveting or press fit. Alternatively, the protruding ends of the first and second pins may be configured to be releasably mounted to an outer surface of one of the two outer chain plate, e.g., by means of a removable screw or a removable locking pin. A releasable engagement between the pins and one of the outer chain plate 201 allows the provision of a chain link that is openable, also known in the art as a splice link.

In another embodiment, see Fig. 11 the first connection portion 203A of the first chain plate 201 may fixedly support a first pin 202A, and the second connection portion 203B of the first chain plate 201 may fixedly support a second pin 202B. The first and second connection portions 203A, 203B may accordingly be provided as generally flat surfaces configured to fixedly receive an abutting end of the respective pins 202A, 202B by means of e.g., welding. In such embodiment, the pins 202A, 202B will be fixed to an inner surface of the first outer chain plate 201.

The second chain plate 201 may be configured with through-going openings 214 in its first and second connection portions 203A; 203B, which openings are configured to receive the other ends of the two pins 202A, 202B. The thus protruding ends of the two pins may be configured to be fixed to the second chain plate by e.g., welding, riveting or press fit. Alternatively, the protruding ends of the two pins may be configured to be releasably mounted to an outer surface of the second chain plate, e.g., by means of a removable screw or a removable locking element 216 (only one illustrated).

Now turning to Fig. 12 one embodiment of a portion of a conveyor chain 1000 is disclosed where the first type (inner) chain links 100 are provided with chain plates 101 according to the invention and as described above, whereas the second type (outer) chain links are provided with chain plates according to prior art. The at least one slit in each leg is provided but not illustrated. Turning to Fig. 13 one embodiment of a portion of a conveyor chain 1000 is disclosed where both the first type (inner) chain links 100 and the second type (outer) chain links 200 are provided with chain plates 101, 201 according to the invention and as described above. The at least one slit in each leg is provided but not illustrated.

The invention is applicable no matter if the conveyor chain is a single pitch conveyor chain or a double pitch conveyor chain.

Also, it is to be understood that the invention is equally applicable to other types of chains than conveyor chains. The invention is by way of example also applicable to e.g., roller chains.

Although not explicitly disclosed or discussed, the conveyor chain may be provided by one or more attachments configured to support a carrier means such as a pin or friction member. The attachment may by way of example be supported by an outer chain plate and may be fixed to or be integral with one of the legs. The skilled person realizes that the number of legs in the chain plates may be two or more.