Abstract:
A chain link for a conveyor chain included in a sup-porting installation, comprising an upper flange ( 17 ) and a lower flange ( 18 ), a first connecting element ( 21 ) and a second connecting element ( 22 ). The first and second connecting elements ( 21, 22 ) are arranged so that the chain link is laterally pivotable relative to a second and a third chain link. The connecting elements ( 21, 22 ) are arranged at a distance (D) from each other in a lon-gitudinal direction (P 1 ) along which the chain link and also the second and the third chain link are arranged, the lower flange being connected to the upper flange and arranged at a distance therefrom seen in a direction per-pendicular to both the longitudinal direction (P 1 ) and a transverse direction (P 2 ) of the chain link. The chain link further comprises a bearing element ( 30 ) which is arranged between the upper flange ( 17 ) and the lower flange ( 18 ) and has a sliding surface ( 31 ), which in the direction (P 1 ) extends between the first ( 21 ) and the second ( 22 ) connecting element, is parallel to a plane coinciding with the hole axes ( 24 ) of the connecting ele-ments and, relative to the connecting elements, is late-rally displaced so that the sliding surface ( 31 ) is mov-able into abutment against and slidable in said direction along a sliding strip ( 35 ).

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a chain link for a conveyor chain included in a supporting installation and more specifically a chain link comprising a first connecting element adapted to connect the chain link to a neighbouring second chain link on a first side, and a second connecting element adapted to connect the chain link to a neighbouring third chain link on a second side opposite the first side, said first and second connecting elements being arranged so that the chain link is laterally pivotable relative to said second and said third chain link, and said first and second connecting elements being arranged at a distance from each other in a direction along which the chain link as well as the second and the third chain link are arranged. The present invention also relates to a conveyor chain comprising a plurality of such chain links as well as a supporting installation comprising such a conveyor chain. 
       BACKGROUND ART 
       [0002]    Supporting installations comprising a conveyor chain with chain links of the type described by way of introduction are used, for instance, in the food industry to support conveyor belts in compact air treatment plants, in which products arranged on the conveyor belt are exposed to an airflow. The airflow can be arranged, for instance, to freeze, cool, dry or heat the products. 
         [0003]    Such a supporting installation can be arranged to support and drive a belt pile, that is a number of belt turns of a conveyor belt, extending helically one above the other in a pile. One or more conveyor chains of the supporting installation can be arranged to support the lowermost belt turn along substantially its entire extent. The conveyor chains are in turn supported by a frame. 
         [0004]    Such supporting installations are known from, for instance, U.S. Pat. No. 4,899,871, U.S. Pat. No. 4,565,282, WO04/045994. 
         [0005]    A conveyor chain frequently comprises a plurality of chain links having bearing seats, which together with a bearing race in a sectional element of the frame define a channel in which bearing elements in the form of balls are arranged. 
         [0006]    Each chain link further comprises connecting elements to allow interconnection of neighbouring chain links, and such connecting elements may have the shape of cylindrical sleeves. 
         [0007]    By the belt pile weight transferred to the frame being transferred eccentrically relative to the bearing elements, the chain links are exposed to a torque which strives to tilt them. For this reason, the frame can have a sliding strip, in which case the connecting elements of the chain links and also the lower flanges of the same abut against the sliding strip to counteract said torque. 
         [0008]    The strain to which the conveyor chain is exposed in operation results in wear on the chain links. Increasing wear on the chain links results in the fact that, to a decreasing extent, they are capable of counteracting said torque, which in turn results in tilting of the chain links of the conveyor chain. When the tilt of the chain links exceeds a certain threshold value, usually about 3-4°, the conveyor chain must be discarded. 
         [0009]    In normal operation, a conventional conveyor chain has a length of service of about 10000-15000 hours. 
         [0010]    However, in some applications it has been found that the chain links of the conveyor chain are subjected to reinforced wear which results in a considerable reduction of the life of service. 
         [0011]    This is a problem especially when the weight of the belt pile is high. 
         [0012]    This problem is sometimes also encountered when the conveyor chain is used in an air treatment plant which is arranged for heating of products since the sliding strip of the frame must in this case be made of a heat-resistant material which frequently exhibits abrasive properties. 
         [0013]    There is thus a need for a supporting installation with a conveyor chain whose chain links are more resistant to wear. 
       SUMMARY OF THE INVENTION 
       [0014]    In view of that stated above, a first object of the present invention is to provide a chain link which is resistant to wear. 
         [0015]    A second object is to provide a chain link which in a relatively easy manner can be restored at a relatively low cost. 
         [0016]    It is also an object of the present invention to provide a conveyor chain comprising such chain links. 
         [0017]    Another object is to provide a supporting installation comprising a conveyor chain with such chain links. 
         [0018]    According to the present invention, there are provided, to achieve at least one of these objects and also other objects that will be evident from the following description, a chain link having the features defined in claim  1 , a conveyor chain having the features defined in claim  11 , and a supporting installation having the features defined in claim  12 . Embodiments of the chain link will be evident from claims  2 - 10  that are depended from claim  1 . 
         [0019]    More specifically, according to the present invention a chain link for a conveyor chain included in a supporting installation is provided, comprising an upper flange and a lower flange, a first connecting element extended along a hole axis and adapted to connect the chain link to a neighbouring second chain link on a first side, and a second connecting element extended along a hole axis and adapted to connect the chain link to a neighbouring third chain link on a second side opposite the first side. The first and second connecting elements are arranged so that the chain link is laterally pivotable relative to said second and said third chain link. The connecting elements are arranged at a distance from each other in a longitudinal direction along which the chain link as well as the second and the third chain link are arranged. The lower flange is connected to the upper flange and arranged at a distance therefrom seen in a direction perpendicular to both said longitudinal direction and a transverse direction of the chain link. The chain link further comprises a bearing element which is arranged between said upper flange and said lower flange and has a sliding surface, which in the direction extends between the first and the second connecting element, is parallel to a plane coinciding with the hole axes of the connecting elements and relative to said connecting elements is laterally displaced so that said sliding surface is movable into abutment against and slidable in said direction along a sliding strip. 
         [0020]    This results in a chain link which has good resistance to wear. This is achieved more specifically by means of the bearing element which, due to the fact that its sliding surface is laterally displaced relative to the connecting elements, ensures that the contact between the connecting elements and said sliding strip is prevented, or in any case minimised. The wear on the chain link will thus be concentrated on said bearing element, whose sliding surface in turn allows the wear to be distributed over a relatively large surface. 
         [0021]    The inventive chain link may have a bearing seat, which makes it possible to arrange a conveyor chain comprising chain links of this type in such a manner that it is capable of taking up the weight of a belt pile via roll elements arranged in a channel which is partly defined by said bearing seat. 
         [0022]    The chain link may also have a recess which allows engagement with a drive device. As a result, a conveyor chain comprising chain links of this type can easily be arranged to drive a conveyor belt. 
         [0023]    The bearing element of the chain link can be detachably arranged. This makes it possible to exchange said bearing element when worn out, thereby eliminating the need for exchange of the entire conveyor chain when worn out to a certain extent. For obvious reasons, this gives considerable economical advantages. 
         [0024]    The bearing element of the chain link can be connected to said connecting elements by a snap lock arrangement and can, to this end, be C-shaped in cross-section and be made of spring steel. Alternatively said bearing element can be L-shaped in cross-section, in which case a resilient tongue is arranged in a base leg for engagement in a hole in the chain link. 
         [0025]    The chain link may also comprise a body, in which two through holes, which are extended along mutually parallel hole axes, are formed, which holes form said first and second connecting elements, said body having a lateral surface which is arranged parallel to said hole axes and forms said bearing element. 
         [0026]    According to the present invention, also a conveyor chain for a supporting installation is provided, comprising a plurality of chain links of one of the types described above. 
         [0027]    Finally, according to the present invention, a supporting installation is provided for supporting and driving a number of belt turns, which extend helically one above the other in a pile and are included in an at least partly self-supporting conveyor belt, comprising a conveyor chain arranged to support an edge portion of the lowermost belt turn along at least part of its extent and comprising a plurality of chain links of the type described above, and a frame which is arranged to support the conveyor chain and which has a sectional element with an elongate bearing race and an elongate sliding strip. 
         [0028]    Embodiments of the present invention will now be described by way of example and with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0029]      FIG. 1  is a schematic perspective view of a supporting installation. 
           [0030]      FIG. 2  is a schematic perspective view of a belt pile. 
           [0031]      FIG. 3  is a perspective view of a supporting installation which supports the lowermost turn of a belt pile. 
           [0032]      FIG. 4  is a perspective view of a first embodiment of an inventive chain link. 
           [0033]      FIG. 5  is a top plan view of the chain link in  FIG. 4 . 
           [0034]      FIG. 6  is a perspective view of a second embodiment of an inventive chain link. 
           [0035]      FIG. 7  is a top plan view of the chain link in  FIG. 6 . 
           [0036]      FIG. 8  is a perspective view of a third embodiment of an inventive chain link. 
           [0037]      FIG. 9  is a side view of the chain link in  FIG. 8 . 
           [0038]      FIG. 10  is a perspective view of a body included in a fourth embodiment of an inventive chain link. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0039]      FIG. 1  illustrates an embodiment of a supporting installation  1  according to the present invention for supporting a helically extending endless conveyor belt  2  as shown in  FIG. 2 , hereinafter referred to as a belt pile  3 . 
         [0040]    The supporting installation  1  can, in combination with the conveyor belt  2 , be used in air treatment plants. The supporting installation  1  and the belt pile  3  are arranged in an enclosing housing through which air flows. 
         [0041]    The sequence of operations of such an air treatment plant can be, for instance, such that a food product is placed on the conveyor belt  2 . Then the product is supplied to the housing through an inlet and treated with air while being conveyed in the helical path of the conveyor belt  2  in the housing. When the food product exits the housing, it is removed from the conveyor belt  2 , which via a return path is returned to the inlet of the housing. 
         [0042]    The supporting installation  2  is arranged to support the belt pile  3  by supporting the lowermost turn of the belt pile  3 . The supporting installation  1  is also arranged to raise the lowermost turn to allow insertion of a new lowermost turn of the belt pile  3 . 
         [0043]    In the embodiment illustrated, the supporting installation  1  is arranged to support the lowermost belt turn of the belt pile  3  along substantially the entire extent thereof. 
         [0044]    To this end, the supporting installation  1  comprises, as shown more distinctly in  FIG. 3  to which reference is now made, two sectional elements  5  which are supported by the frame  4  and which are extended each along an endless path and which are each arranged to support a lateral edge  6  of the lowermost belt turn of the conveyor belt  2  via a conveyor chain  7 . 
         [0045]    Each conveyor chain  7  runs along a conveyor belt supporting portion  8  and a return portion  9 . The conveyor belt supporting portion  8  extends substantially along the entire lateral edge  6  of the lowermost turn of the conveyor belt  2 , which lateral edge  6  is adapted to be supported by the associated sectional element  5  via the conveyor chain  7 . 
         [0046]    The supporting installation  1  can be arranged to support wholly or partly self-supporting conveyor belts  2 . 
         [0047]    By a self-supporting conveyor belt  2  is meant that at least one lateral edge  6  of a superjacent turn of the belt pile  3  rests on a corresponding lateral edge  6  of a subjacent turn of the belt pile  3 . 
         [0048]    The supporting installation  1  shown in  FIG. 1  is intended for an entirely self-supporting conveyor belt  2  as shown in  FIG. 2 , which consequently means that a subjacent turn of the belt pile  3  supports a superjacent turn. 
         [0049]    The supporting installation  1  is further arranged to drive the conveyor belt  2 . In the shown embodiment, said driving of the conveyor belt  2  is performed by advancing the associated conveyor chain  7 . Each conveyor chain  7  is advanced by a meshing gear wheel  10 , which in turn is driven by an electric motor  11 . Each gear wheel  10  engages the associated conveyor chain  7  along the return portion  9  thereof. 
         [0050]    However, it will be appreciated that the supporting installation need not be arranged to drive the belt pile but that said driving can be performed in other ways. For instance, it is possible to arrange an interior driving drum, which engages the inside of the belt pile along the entire, or parts of, the height thereof. The supporting installation can also be arranged to drive a belt pile together with a driving drum. The supporting installation can then have a conveyor chain which supports an outer edge of the lowermost turn of the belt pile, while the driving drum engages the inside of the belt pile. 
         [0051]    The conveyor belt supporting portion  8  of each conveyor chain  7  has a pitch and consequently takes the shape of a helical turn. The belt pile  3  is thus formed when the opposite lateral edges  6  of the conveyor belt  2  run along the respective conveyor belt supporting portions  8  of the conveyor chains  7 . In the embodiment shown, the conveyor belt supporting portions  8  are substantially circular, whereby the formed belt pile  3  takes on a circular cylindrical shape. However, it will be appreciated that the conveyor belt supporting portions  8  can have other shapes, for instance elliptic, whereby the formed belt pile  3  takes on an elliptic cylindrical shape. 
         [0052]    The pitch of the conveyor belt supporting portions  8  is such as to correspond to the height of the conveyor belt  2 . This means that when the lower turn of the conveyor belt  2  has extended one turn along said conveyor belt supporting portions  8 , this turn is piled on a new lowermost turn of the conveyor belt  2 . 
         [0053]      FIG. 3  illustrates the supporting installation  1  in cooperation with the lowermost belt turn of a belt pile  3 . 
         [0054]    As mentioned above, the belt pile  3  is formed from a helically extending conveyor belt  2 . 
         [0055]    In the embodiment shown, the conveyor belt comprises link elements  12  in succession, which are hingedly connected to each other and which each comprise two opposite side plates  13  which are interconnected by transverse rods  14 . 
         [0056]    The lower belt turn has two lateral edges  6 , which are formed by the underside of the respective side plates  13 . 
         [0057]    Each lateral edge  6  rests on an associated conveyor chain  7  of the supporting installation  1 . 
         [0058]    Each conveyor chain  7  is in turn supported by the frame  4  via a sectional element  5 . 
         [0059]    Each conveyor chain  7  is further mounted on bearings so as to be movable along the associated sectional element  5 . 
         [0060]    The conveyor chains  7  comprise a plurality of alternately arranged outer  15  and inner  16  chain links. More specifically, the outer chain links  15  are spaced from each other, each outer chain link  15  overlapping and being hingedly connected to two inner chain links  16 . 
         [0061]      FIGS. 4 and 5  show a first embodiment of such an inner chain link  16 . 
         [0062]    The inner chain link  16  comprises an upper flange  17  and a lower flange  18 . The upper flange  17  is in a first lateral portion  19  connected to the lower flange  18  via a first connecting element  21  and a second connecting element  22 . 
         [0063]    The first and the second connecting element  21 ,  22  are formed as cylindrical sleeves  23 , which each extend along a hole axis  24 . 
         [0064]    The first connecting element  21  allows connection of the inner chain link  16  to a neighbouring outer chain link  15  on a first side  25 , and the second connecting element  22  allows connection of the inner chain link  16  to a second neighbouring outer chain link  15  on a second side  26  opposite the first side  25 . The first and the second connecting element  21 ,  22  are arranged so that the chain link  16  is laterally pivotable relative to said outer chain links  15 . 
         [0065]    The chain links  15 ,  16  of the conveyor chain shown in  FIG. 3  are interconnected by pins  27 . Each pin  27  has a head portion (not shown) with a first diameter and opposite end portions with a second diameter which is smaller than said first diameter. The outer chain link  15  has a hole whose diameter corresponds to said second diameter. Holes are formed in the upper and the lower flange  17 ,  18  of the inner chain link  16 , which holes are aligned with a through hole of the respective sleeves  23  to provide an inner diameter of the respective connecting elements  21 ,  22 , which inner diameter is greater than the diameter of the head portion of the pin  27 . Finally the head portion of the pin  27  has a length which exceeds the sum of the length of the sleeve  23  and the thickness of the upper and the lower flange  17 ,  18 . 
         [0066]    For connection of an outer chain link  15  to an inner chain link  16 , the hole of the outer chain link  15  is thus aligned with one connecting element  21 ,  22  of the inner chain link  16 . Subsequently a pin  27  is inserted from below so that its one end portion projects through the hole of the outer chain link  15 . Said end portion can then be upset in a suitable manner for locking of the pin  27 . Finally, a washer can be arranged around the opposite end portion and is then correspondingly upset. This results in an interconnection with a play allowing mutual turning both horizontally and vertically between the inner chain link  16  and the outer chain links  15 . 
         [0067]    The connecting elements  21 ,  22  are further arranged at a distance D from each other in a direction P 1  along which the inner chain link  16  and the outer chain links  15  are arranged. 
         [0068]    By the connecting elements  21 ,  22  being arranged at a distance D from each other, a space is formed between them, into which teeth of a gear wheel  10  can be inserted for engagement with the chain link  16  to advance the conveyor chain  6  and thus drive the belt pile  3  supported by the supporting installation  1  via said conveyor chain  7 . 
         [0069]    The upper flange  17  of the inner chain link  16  further has a bearing seat  28  in a second lateral portion  20  opposite the first lateral portion  19 . More specifically, the bearing seat  28  is formed by the upper flange  17  of said second lateral portion  20  having a curved inside  29 . 
         [0070]    The inner chain link  16  further comprises a bearing element  30  with a sliding surface  31 , which in said direction P 1  extends between the first and the second connecting element  21 ,  22  and is, relative to them, laterally displaced in a direction P 2  towards the second lateral portion  20  of the upper flange  17 . 
         [0071]    It will be appreciated that the bearing element  30  can be so laterally displaced that its sliding surface  31  is arranged in a plane which is tangent to the connecting elements  21 ,  23 . 
         [0072]    The lower flange  18  extends in said direction P 2  towards the second lateral portion  20  of the upper flange  17  so that it projects from said sliding surface  31 . 
         [0073]    It will be appreciated that the inner chain link  16  could be connected to neighbouring chain links of the same type by using a suitably designed connecting means. 
         [0074]      FIG. 3 , to which reference is now made once more, shows, as mentioned above, the sectional elements  5  which support the conveyor chains  7 . 
         [0075]    Each sectional element  5  has a bearing race  32  which extends at least along substantially the entire conveyor belt supporting portion  8  of the respective conveyor chains  7 . The bearing race  32  defines, together with the bearing seats  28  of the chain links  16 , a channel, in which roll elements  33  in the form of balls  34  are arranged. 
         [0076]    The roll elements  33  cooperate with the respective sectional elements  5  to take up both vertical and radial forces which are exerted by the conveyor belt  2  on the frame  4  via the conveyor chains  7 . 
         [0077]    Moreover each sectional element  5  has a sliding strip  35  extended at least along said conveyor belt supporting portion  8 . 
         [0078]    As shown in  FIG. 3 , the lateral edges  6  of the lowermost belt turn are slightly displaced in the lateral direction relative to the roll elements  33 . By the weight of the belt pile  3  being eccentrically transferred relative to the roll elements  33 , the chain links  16  are exposed to a torque which strives to tilt the chain links. This torque is counteracted due to the fact that the sliding surface  31  of the bearing element  30 , together with a horizontal abutment surface  37  of the lower flange  18 , abuts against the sliding strip  35 . 
         [0079]    As mentioned above, the sliding surface  31  extends between the first and the second connecting element  21 ,  22  and is laterally displaced relative to the same. More specifically, the sliding surface  31  is laterally displaced so that the sliding surface  31  is movable into abutment against and slidable along the sliding strip  35 . The sliding surface  31  is further arranged in a plane which is parallel to a plane coinciding with the hole axes  24  of the connecting elements  21 ,  22 . 
         [0080]    If the sliding surface is arranged in a plane which is tangent to the connecting elements  21 ,  22 , they too will make contact with the sliding strip when the sliding surface  31  of the bearing element  30  is moved into abutment against the sliding strip. 
         [0081]    The bearing element  30  further has a bevel  36  along the associated vertical lateral edge of the sliding surface  31 . The purpose of the bevels  36  is to prevent cutting or planing engagement between the sliding surface  31  and the sliding strip  35 . 
         [0082]    According to the present invention, a supporting installation  1  is thus provided with at least one conveyor chain  7  comprising chain links  16  which are less prone to wearing out due to high load or abrasive materials with respect to the sliding strip  35  of the sectional element  5 . More specifically this is achieved by means of a bearing element  30  with a sliding surface  31 , which is extended between the connecting elements  21 ,  22  of the chain link  16  and is laterally displaced relative to the same so that the sliding surface  31  is movable into abutment against and slidable along the sliding strip  35 . The sliding surface  31  thus provides a large contact surface between the sliding strip  35  and the chain link  16 , thereby distributing the wear on the chain link  16  over a larger surface. At the same time it will be possible to prevent contact, or at least minimise the contact, between the connecting elements  21 ,  22  and the sliding strip  35 , which means that the connecting elements will not be subjected to considerable wear. As a result, the life of service of each chain link  16 , and thus also of the conveyor chain  7 , will be extended, which for obvious reasons gives advantages in terms of cost and production. 
         [0083]    The inventive chain link is expected to have so good resistance to wear that the life of service of a conveyor chain comprising such chain links is not determined by the wear that arises as they engage the sliding strip. The life of service will instead be determined by other factors, such as tension and load. 
         [0084]    It will be appreciated that the present invention is not limited to the embodiment described above. 
         [0085]    Alternative embodiments of inventive chain links will now be described. Components with a similar function have been given the same reference numerals throughout the text. 
         [0086]      FIGS. 6 and 7 , to which reference is now made, illustrate an inventive chain link  16  having a replaceable bearing element  30 . A worn-out bearing element  30  can thus easily be replaced with a new. This results in one more advantage. The fact that the chain link  16  has a bearing element  30  implies that the wear is distributed over a relatively larger surface, and therefore the chain link can be used for a longer period of time before wear causes the chain link to tilt above a predetermined threshold value. Moreover the fact that the bearing element can be replaced means that the chain link can easily be restored to its original state at a low cost. 
         [0087]    More specifically, the bearing element  30  is arranged so that it is connected to the connecting elements  21 ,  22  of a chain link  16  by a snap lock function. To this end, the bearing element  30  is made of spring steel and is substantially C-shaped in cross-section. This makes it possible to fix the bearing element  30  by snap action so that its end portions  38  each grasp a connecting element  21 ,  22 . 
         [0088]      FIGS. 8 and 9 , to which reference is now made, illustrate another embodiment of an inventive chain link  16 . Also this chain link  16  comprises a replaceable bearing element  30 , which in this case is made from an L-shaped sectional element, which can be secured by a snap lock function. 
         [0089]    The free end  39  of the upright leg  40  of the L-shaped sectional element may have a projection  42 , which is insertable into a complementarily formed hole  43  in the upper flange  17  of the chain link. Moreover a resilient tongue  44  is arranged in the base leg  41  of the L-shaped sectional element, which tongue  44  is arranged for cooperation with a complementary hole  45  which is formed in the lower flange  18  of the chain link  16 . To fasten the bearing element  30 , the L-shaped sectional element is angled, after which said projection  42  is inserted through said hole  43  in the upper flange  17 . Subsequently the L-shaped sectional element is turned upwards so that the side, facing away from the connecting elements  13 , of the upright leg  40  forms a sliding surface  31  parallel to the hole axes  24  of the connecting elements  21 ,  22 . The tongue  44  of the base leg  41  will thus be moved to a position, in which, by snap action, it is moved into the hole  45  formed in the base leg  40 . An advantage of this embodiment is that the upper side of the base leg forms an abutment surface  37  which can easily be replaced when worn out. 
         [0090]      FIG. 10  illustrates another embodiment of an inventive chain link. In this embodiment, the connecting elements  21 ,  22  and the bearing element  30  are formed in one piece, and the Figure thus shows a body  46 , in which two through holes  47  with parallel hole axes  24  are formed. The holes  47  form said first and second connecting elements  21 ,  22 , the body  46  having a lateral surface  48  which is arranged parallel to said hole axes  24  and forms the sliding surface  31  of said bearing element  30 . A recess  50  can be formed in the lateral surface  49 , opposite said sliding surface  31 , of the body  46  and be arranged to engage a gear wheel for advancing a conveyor chain provided with chain links according to this embodiment, and thus driving the belt pile  3  supported by the supporting installation  1  via said conveyor chain  7 . The body  46  is adapted to be arranged between, and connected to, an upper flange (not shown) and a lower flange (not shown) as described above in connection with the other embodiments. 
         [0091]    Several modifications and variations are thus conceivable, and therefore the scope of the present invention is exclusively defined by the appended claims.