Abstract:
A conveying means ( 1 ) is described having running rollers ( 7 ) which can be supported on a guide ( 2 ). At least one running roller ( 7 ) is mounted on a roller lever ( 12   a ) which can be pivoted between a first and a second position with the aid of a pivoting mechanism ( 13, 33 ) and can be locked in a position. In order to make a conveying means of this type simpler in structural terms and less susceptible to wear, it is proposed to equip the pivoting mechanism ( 13, 33 ) with a toggle lever ( 14 ) which is connected to an actuating element ( 21 ), wherein the toggle lever comprises a first and a second lever element ( 14   a,    14   b ) which are connected to one another via a joint ( 15 ).

Description:
[0001]    The present application claims the benefit of priority of International Patent Application No. PCT/EP2007/000485, filed on Jan. 20, 2007, which application claims priority of German Patent Application No. 10 2006 012 148.1, filed Mar. 16, 2006. The entire text of the priority application is incorporated herein by reference in its entirety. 
     
    
     FIELD OF THE DISCLOSURE 
       [0002]    The disclosure relates to a conveyance means of the type used as an accumulator or dynamic storage device between work station, for example, and also to a chain link and a conveyance device. 
       BACKGROUND 
       [0003]    A conveyance means, a chain link, and a conveyance device of this type are known from WO 2005/073113. The known conveyor chain is used in a conveyance device for the dynamic storage of objects. For this purpose, a conveyance means which is designed as a conveyor chain is guided in a guideway between a feed station and a delivery station in an endless way. The conveyor chain acts as pull strand in one area, and as a return strand in another area, where the length of the pull strand and of the return strand is variable, and can be adjusted depending on the quantity of objects to be conveyed or stored. To vary the length of the pull strand and of the return strand, a sliding carriage is provided, which runs on mutually parallel sections of the guideway. The sliding carriage contains in each case a curved deflection member for the pull strand and for the return strand, so that, as a result of the shifting of the sliding carriage along the guideway areas, the portion of the conveyor chain that acts as pull strand can be increased or decreased, compared to the portion of the return strand. The conveyor chain is supported by track rollers on the guideway. However, in the transition from the guideway to the sliding carriage it is necessary for at least some of the track roller to be rendered inoperative temporarily to separate the track rollers from the guideway, and to guide them either onto the sliding carriage, or from the sliding carriage back onto the guideway. In the known conveyor chain, this is achieved by constructing at least one track roller so it can be swiveled, where the swiveling occurs with the help of a swivel mechanism. With the swivel mechanism of the known conveyor chain, this occurs via a pawl which is prestressed with a torsion spring. The pawl acts together with a cross bolt, which is arranged parallel to the rotation axle and connected to the track roller. The pawl is designed so that it stops the track roller in its engaged position with the guideway, when the pawl is engaged with the cross bolt. The pawl is connected to an actuation finger, which can be moved by a control surface associated with the sliding carriage so that the pawl is moved against the force of the spring out of its engagement with the cross bolt, and thus releases the track roller for swiveling. The swivel position of the track roller is then defined by a grooved curve on the sliding carriage. As soon as the track roller needs to be again in its normal conveyance position, it is swiveled back by the grooved curve, and then the pawl is moved again into engagement with the cross bolt, and the track roller is stopped. The pawl thus must abut in the pull strand and in the return strand against the cross bolt during each pass of the sliding carriage, causing, on the one hand, unnecessary noises, and, on the other hand, an increase in wear. In addition, two control curves are necessary, one for the pawls and one for swivelling the rollers. 
       SUMMARY OF THE DISCLOSURE 
       [0004]    The disclosure is thus based on the problem of providing a conveyor chain of the mentioned type with an improved and simplified swivel mechanism. 
         [0005]    By using a knee lever, the swivel mechanism can be simplified decisively. The knee lever can be connected directly to the roller lever of the track roller, and, accordingly, it does not have to abut against across bolt or other construction elements to swivel the track roller. In addition, only one control curve for the knee lever is required. 
         [0006]    Thus, a knee lever continues to offer the decisive advantage that, to stop the track roller in a certain position, lever members of the knee lever only need to be stopped in a certain position relative to each other. This can occur by means of spring elements of the greatest variety, self inhibition, magnetic elements, or similar devices. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    Embodiment examples of the disclosure are explained in greater detail below with reference to the drawing. In the drawing: 
           [0008]      FIG. 1  shows a schematic representation of a conveyance device with which the present disclosure can be used, 
           [0009]      FIG. 2  shows an enlarged detail of  FIG. 1 , 
           [0010]      FIG. 3  shows a first embodiment example of the disclosure, 
           [0011]      FIG. 4  shows the embodiment example according to  FIG. 3  with a swiveled track roller, 
           [0012]      FIG. 5  shows a perspective representation of an additional embodiment example of the disclosure, 
           [0013]      FIG. 6  shows a chain link according to the disclosure in a first use, and 
           [0014]      FIG. 7  shows a chain link according to the disclosure in a second use. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    The invention is described below in reference to a conveyance device F with a dynamic storage device V 1 , but it can be used in all cases where it is necessary or appears desirable to swivel a track roller of a conveyance means in a controlled way. 
         [0016]    In the represented embodiment example according to  FIG. 1 , the conveyance device F corresponds to the conveyance device according to WO 2005/073113 whose disclosure content is herewith included by reference. The conveyance device F is preferred for conveying objects G, such as, bottles or containers, between different work stations, such as, for example, between a stretch blow molding machine and a labeling machine, or between a filling machine and a closing machine, and a packaging machine or a similar device, and it contains substantially a single, endless conveyance means  1  in the form of a roller chain, i.e., in the form of a link or conveyor chain which is provided with a track roller for transporting objects G. The conveyance means  1  is guided through a stationary guideway  2  in such a way that it moves past a feed station E and a delivery station A. The conveyance means  1  is driven in the area of the feed station through a first drive device  3  by a motor M, and in the area of the delivery station A through a second drive device  4  by a motor M. The feed and delivery stations E and A are followed by a first, freely guidable area, which, in the represented embodiment example, is a longitudinal oval area OV of the guideway  2 . Moreover, the dynamic storage device V 1  contains helical areas  2   a,    2   b  of the guideway  2 , which run mutually parallel and at equal separation from each other. In these areas  2   a,    2   b,  a sliding carriage  5  can be moved, which is represented in greater detail in  FIG. 2 . With the help of this sliding carriage  5 , the length of the pull strand of the conveyance means  1  between the feed station E and the delivery station A can be adapted to the quantity of objects to be conveyed, to lengthen or shorten the pull strand with respect to the return strand between the delivery station A and the feed station E. 
         [0017]    To achieve this, the sliding carriage  5 , as shown in  FIG. 2 , contains a first 180° deflection member  5   a  and a second 180° deflection member  5   b,  opposite the deflection member  5   a.  Each deflection member  5   a,    5   b  interconnects opposite places of the parallel areas  2   a,    2   b  of the guideway  2  in such a way that the conveyance means can move from the area  2   a  into the area  2   b.  The first deflection member  5   a  is associated with the pull strand and the second deflection member  5   b  with the return strand. 
         [0018]    The sliding carriage  5  is moved along the parallel areas  2   a,    2   b  as a result of a difference in the speeds of the drive stations  3  and  4 . To shorten the pull strand of the conveyance means  1 , the sliding carriage  5  is moved through the conveyance means  1  as a result of an appropriate difference in the speeds of the drive stations  3  and  4  in the direction to wards the feed station E and the delivery station A. To shorten the return strand, the sliding carriage  5  is moved away from the feed station E and the delivery station A due to an appropriate difference in the speeds of the drive stations  3  and  4 . 
         [0019]    The conveyance means  1  is supported, as shown in  FIG. 2 , right side, by the track rollers  7  on the guideway  2 . The guideway  2  can be of any appropriate shape, for example, it can contain two or more parallel rods, profiles of different cross sections, or similar parts. Moreover, as can be seen particularly in  FIG. 1 , twisted places can be provided to swivel the objects G to be contained in a horizontal position and back again. 
         [0020]    In the represented embodiment example, the conveyance means consists of a plurality of chain link-like structures  8 , which are interconnected one after the other by articulations, and which each carry track rollers  7  and a hold device  9  for the objects G. The chain links  8  must be such that they cannot move by themselves, thus they may also present a design which would lead to an unstable position of the rollers on the guideway if the individual chain links  8  do not support each other mutually. Such a chain link  8  is represented in greater detail, for example, in  FIGS. 3 and 4 . The fork-like chain link  8  receives a carrier  10 , on whose two ends bearing elements  11   a,    11   b  are provided to connect by articulation a plurality of the chain links  8  to form the endless conveyance means  1 . It is preferred for the storage means  11   a,    11   b  to contain an articulation which can be swiveled to all sides, for example, a cup and ball bearing, so that the conveyance means  1  can move in space. On the support  11 , the track rollers  7  are also attached at places which are determined by the guideway  2  and in an orientation determined by the guideway  2 . The track rollers  7  of  FIGS. 3 and 4  are designed, for example, for parallel, superposed rods ( FIG. 7 ) or a roof-shaped running profile of the guideway  2  or a similar part. On the chain link  8 , four track rollers  7  are provided, which are attached rotatably in pairs to a roller lever  12   a  and  12   b,  respectively, which is constructed as a double lever. The roller levers  12   a,    12   b  protrude on both sides from the support  10 , resulting in a substantially T-shaped arrangement of the roller levers  12   a,    12   b  with respect to the support  10 . 
         [0021]    At least one of the roller levers, in the represented embodiment example roller lever  12   a,  is attached rotatably to the support  10  via a rotation axle  12 ′ in such a way that it can form with the support  10  an angle that is different from 90°. The other roller lever  12   b  is fixed in a 90° position with respect to the support  10  to the latter. However, as needed, the roller levers  12  can be connected at other angles or in another way to the support  10 . 
         [0022]    To move the swivelable roller lever  12   a  in an angular position that deviates from the roller lever  12   b  with respect to the support  10 , a spring-loaded swivel mechanism  13  is provided. The swivel mechanism  13  contains a knee lever  14 , which contains a first and second lever member  14   a,    14   b,  which are connected via an articulation  15  to each other in a way which allows swiveling. The first lever member  14   a  is connected to the swivelable roller lever  12   a  via an articulation  6  in such a way that, if the lever element  14   a  is moved, the roller lever  12   a  can be swiveled about its axle  12 ′. For this purpose, the first lever element  14   a  engages, at a separation from the axle  12 ′, on the roller lever  12   a.  The second lever element  14   b  is attached in a way which allows swiveling to the support  10  about an axle  16  formed by a bearing pin or similar part. A first abutment  17   a  and a second abutment  17   b,  as well as an articulation point  18  in the form of an attachment pin or similar part, are firmly attached to the second lever element  14   b,  and they can be swiveled with the latter element about the bearing pin  16 . The articulation point  18  serves to attach a spring element, here a tension spring  19 , which is firmly applied with its other end to an articulation point  20  on the support  10 . The articulation point  18  presents a separation with respect to the rotation axle  16 , and it is arranged in such a way that a straight connection between the articulation points  18  and  20  does not pass through the rotation axle  16  in the two end positions according to  FIGS. 3 and 4 . 
         [0023]    Moreover, an actuation element  21 , in the form of an actuation pin or a similar part, which protrudes over the support  10 , is firmly connected to the second lever element  14   b  of the knee lever  14 . 
         [0024]    The knee lever  14  and the arrangement of the articulation points  18 ,  20  of the tension spring  19  is constructed in such a way that the two roller levers  12   a,    12   b  are located in a parallel position with the same orientation if the two lever members  14   a,    14   b  assume a relative position with respect to each other forming a large, obtuse angle which, however, is preferably different from 180° ( FIG. 3 ). In this relative position of the lever members  14   a,    14   b,  the parallel position of the roller levers  12   a,    12   b  is determined by the abutment  17   b  which abuts against a counterpiece fixed to the support, and which is stopped by a spring  19  located on one side of its dead center. Thus, the spring  19  ensures a bistable stopping of the knee lever  14  in the two end positions defined by the abutments  17   a,    17   b  on both sides of the stretch position. In addition, it supports, if needed, the approach to these end positions, so that the control surfaces  22  in each case need to swivel the lever member  14   b  only until the spring  19  has passed its dead-center or stretch position. The stabilization in the parallel position of the swivel lever  12   a  according to  FIG. 3  is additionally supported by the fact that the articulation  15  lies slightly under the connection line drawn with a dot and dash between the articulation  6  and the axle  16 . 
         [0025]    The scissor position of the two roller levers  12   a,    12   b  shown in  FIG. 4  is defined by a relative position of the lever members  14   a,    14   b  forming a smaller, obtuse or acute angle, which is determined by the abutment  17   a  being applied to a counterpiece which is firmly attached to the support. To reach this position, the first lever element  14   b  pulls the second lever element  14   a  along, while the articulation point  18  of the spring  19  moves over the dead center into its second stopping position, in which the position of the roller levers  12   a,    12   b  shown in  FIG. 4  is stopped. 
         [0026]    The swiveling of the lever element  14   b  and thus of the roller lever  12   a  on the support  10  is effected by the actuation element  21  coming in contact with a control surface  22  ( FIG. 2 ), which is arranged there on the sliding carriage  5 , where it is necessary to separate at least apart of the track rollers, for example, the track rollers in the outer portion of the curve at the transition between the parallel areas  2   a,    2   b  and the deflection members  5   a,    5   b,  from the guideway  2 , and bring them back in engagement with the guideway  2 . As shown in  FIG. 2 , the control surface  22  is preferably constructed as a curved ramp. However, it should be pointed out that the design of the control surfaces and their arrangement and orientation must obviously be adapted to the type of the chain link  8 . 
         [0027]      FIG. 5  shows an additional embodiment example of a chain link  28 , which corresponds to the chain link  8 , except for the details described below. The first chain link  28  also contains a knee lever  14  whose first lever member  14   a  is connected in a way which allows swiveling to the swivelable roller lever  12   a  by means of an articulation  6 , and whose second lever member  14   b  is connected to an actuation element  21 . The actuation element  21  actuates a rotation pin  29 , to which the second lever member  14   b  is attached. The swivel mechanism  33  of the chain link  28  again contains a spring element, which, however, is designed as a torsion spring here, preferably as two torsion springs  30   a,    30   b.  Each one of the torsion springs  30   a,    30   b  with one of its ends abuts against the knee lever  14  in a relative position of the two lever members  14   a,    14   b,  which corresponds to the parallel position of the roller levers  12   a,    12   b.  The other end of the torsion springs  30   a,    30   b  rests with firm connection on the support. When the actuation element  21  engages with an appropriate control surface  22 , then the rotation pin  29  together with the knee lever  14  turns against the force of the torsion spring  30   a,    30   b  in a relative position, which corresponds to the scissor position of the roller levers  12   a,    12   b.  However, as soon as the engagement between the actuation element  21  and the control surface  22  is released, the spring element  30  presses the knee lever  14  again into a relative position of its lever members  14   a,    14   b,  which corresponds to the parallel position of the roller levers  12   a,    12   b.    
         [0028]      FIGS. 6 and 7  show embodiment examples of the chain links  38  and  48 , respectively, which are adapted by means of different holding devices for the transport of different objects G. The chain link  38  contains an elastic gripper  39 , by means of which a bottle or container-shaped object G can be gripped, for example, under a neck area or a protruding carry ring  35 . The gripper  39  is connected via a gripper support  36  to the support  10  of the chain link  38 . 
         [0029]      FIG. 7  shows an additional chain link  48 , which is equipped with a holding device in the form of a base plate  49 , on which the objects G can be transported in a standing or lying position. The base plate  49  as well is firmly connected via plate support  45  to the support  10  of the chain link  48 . 
         [0030]    In contrast to the described and drawn embodiment examples, the attachment devices for the objects can be of any appropriate shape. Magnets can be used instead of spring elements to stop the position of the swivelable roller lever and/or as actuation elements to swivel the roller lever. The roller levers can also be designed as a one-sided lever, and provided with one track roller or with a set or track rollers. The actuation element does not necessarily have to engage on one of the lever members, rather, it can engage also on the articulation, for example. Moreover, the disclosure can be applied not only with conveyor chains, but also with other conveyance means, for example, with self-driven vehicles. Using an appropriate elastic design of the lever members, it is possible to omit additional spring elements. The abutments used to define the end position of the knee lever can also be attached to the swivelable roller lever. The lever member which is attached to the chain link can also turn over in one direction like a crank.