Abstract:
The present invention relates to a sorting unit having tipable troughs that are selectively tipable by a combination of levers and cams running within predefined tracks. The tipping action can be selectively controlled so as to accommodate items within the troughs of varying weights, coefficient of frictions and the like.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The invention relates to a sorting conveyor with a number of transport cars that have laterally tipping delivery troughs for the package freight being sorted.  
           [0002]    A sorting conveyor of this type is known from German patent DE 40 42 708 C2. Herein, a sorting conveyor is described which has a series of revolving support units for laterally tipping delivery troughs that are moved along a conveyor chassis past a storage station where they are loaded with the package freight that is to be sorted. The support units loaded with the package freight are then moved past a series of unloading or receiving stations, in which the delivery troughs can be selectively tipped by means of control arms disposed on both sides, so that the package freight being sorted can be unloaded. The support units are implemented as transport cars or transport units with guide elements which engage in the conveyor chassis at a relatively great distance from each other. The transport cars are fitted with elongated drive elements which extend in the direction that the support units are pushed and which are designed to work in conjunction with linear motors. These are attached in fixed positions along the conveyor chassis.  
           [0003]    With this type of sorting conveyor it is known that the delivery troughs are tipped by means of a tipping device, with the tipping device engaging the control arm in running slots by means of a cam follower roller, thereby causing the tray to tip.  
           [0004]    It is also already known from European patent EP 0 173 399 B1 that the cam follower roller must be engaged in the running slots through a controlled movement at right angles to the direction of travel.  
           [0005]    This provides a mechanism for tipping the delivery troughs selectively. Depending on the speed of the conveyor, the tipping of the delivery troughs will also be assisted by the article being sorted, which will slide outwards when the tipping process starts. This is because the center of gravity of the delivery trough will inevitably be shifted outwards towards the unloading station.  
           [0006]    There is, however, a fundamental problem with the aforementioned tipping conveyor due to the fact that the items of package freight being tipped can have quite different slide characteristics because of their external features. This can place a considerable mechanical load on the guide running slots, or can even cause the delivery trough to return to its basic position, particularly in the case of comparatively heavy items of package freight that do not slide easily. As a result, another attempt will have to be made to carry out sorting in such a case, or the item in question may even have to be sorted by hand. This will adversely affect the performance of the sorting conveyor.  
           [0007]    This problem can be solved by increasing the maximum possible tipping angles. The items of package freight that have a comparatively poor slide characteristic will then be sufficiently accelerated. However, the items of package freight with good slide characteristics could then start to move too fast and could possibly overturn. As a result, the address, which is normally on the top, could end up on the bottom or the side.  
           [0008]    This disadvantage could in turn be removed by an appropriate design of the delivery trough. When package freight is being sorted, it must therefore be possible to selectively adapt the sorting conveyor so that different delivery troughs and tipping angles can be implemented in order to meet different requirements. Sorting conveyors known from the prior art are directed away from the following advantages and solutions.  
         SUMMARY OF THE INVENTION  
         [0009]    An advantage of the present invention is to provide a sorting conveyor that can be especially equipped to meet specific requirements and which can also sort comparatively heavy items of package freight safely and reliably even if they do not have particularly good slide characteristics.  
           [0010]    These and other advantages are achieved with a sorting conveyor set out herein, comprising the following features:  
           [0011]    the transport cars have a support unit for the delivery troughs that swivels round a tipping axis;  
           [0012]    there is a lever arm that can engage in running slots and can act on the support unit;  
           [0013]    the transport cars consist of a base module that holds the support unit; and  
           [0014]    the base module has guide elements for the tipping movement of the support unit, and it provides a lifting movement of the lever arm that initiates the tipping movement.  
           [0015]    Accordingly, the tipping device acts directly on the support unit, so that different delivery troughs can be used and the delivery troughs can be easily replaced. Furthermore, the pressure of the gravitational effect of the item of package freight is cushioned particularly well in the transport cars, because the lever arm engages in the base module that is equipped with the guides, and it is also held there. In addition, the creation of the base module provides a particularly simple design for the transport cars. Thus, for example, a base module comprising two parts is feasible, with the two halves being reverse images of each other and having guide rails in the form of cavities, thereby restricting the mobility of the support unit and of the lever arms in a two-dimensional plane.  
           [0016]    Different tipping angles can easily be achieved through the selection of an appropriate base module. So that the structure of the transport cars described above can be used to particular advantage, provision is made for locking the lever arms, and therefore the delivery troughs, in their basic and tipping positions. This makes it possible to retain the delivery troughs securely in their tipping position without the need to engage the tipping mechanism further in a running slot which would otherwise be subjected to a comparatively heavy mechanical stress if the load comprised particularly heavy items of package freight and if these items did not have particularly good slide characteristics. Because engagement in the running slots is shorter, the size of the running slots can be comparatively small, and the noise level suffered by personnel as a result of the deflection roller running in the running slots is comparatively low.  
           [0017]    Another particular advantage of the aforementioned design can be utilized by the lever arms engaging in two-dimensional running slots. This is because the lever arm has essentially only to carry out a vertical linear movement, either upwards or downwards, in order to tip the delivery trough. For this purposes it therefore engages in the base module.  
           [0018]    A further advantageous embodiment of the invention provides for the lever arm acting on a slide seating on the support unit without a bearing, which means that there is no need for an additional bearing and its assembly.  
           [0019]    In an alternative or additional development of the invention, the height of the sorting conveyor will be made low when the delivery troughs can be tipped to both sides, and two moveable lever arms are provided that are independent of each other and that act on the support unit on a slide seating. Accordingly, only one of the two lever arms will be moved upwards or downwards to achieve tipping, with the support unit moving past the other lever arm that has not been activated. This embodiment variant is especially favorable with a lever arm that is active in the upward direction, because the other lever arm is not correspondingly pressed passively downwards. For this reason, there is no need to provide space for this lever arm, which, in the prior art, is typically moved passively.  
           [0020]    A particular advantage of this design is that a maximum tipping angle of the support unit can be specified by an appropriate implementation of the guide elements. In this way, different tipping angles can be implemented simply by using correspondingly different base modules, with the lever arms and the support unit as such remaining essentially unchanged.  
           [0021]    In a particularly preferred embodiment variant, the lever arm logically has protruding pot-shaped cams. By means of these cams, it engages in an essentially vertical guide rail, with the basic and end positions being implemented by means of a locating position that branches laterally from the guide rail.  
           [0022]    This embodiment includes a feature that significantly improves operating reliability. This is that a lever arm that tips the support unit swivels the support unit when the unlocking movement starts so that the other lever arm cannot be unlocked. Operating reliability will also be particularly improved if the aforementioned feature is extended so that the lever arms can be engaged in the running slots by means of a control element that can be engaged in an engaged position, with these elements being slightly offset in relation to each other, seen in the direction of travel. Accordingly, only the following one of the two engaging elements looked at in the direction of travel will be destroyed in the event of a faulty engagement attempt (with both engaging elements set in position). But damage to the transport cars and/or to the running slots will certainly be avoided as a result. The entire sorting conveyor, apart from this one destination position that can no longer be served or that can only be served from one side, can therefore continue to be operated. This helps to ensure a high degree of availability for the sorting conveyor.  
           [0023]    An alternative variant to the embodiment explained above provides for a two-part structure of the lever arm with a cover and a deflection lever. The cover engages with a slide seating on the support unit and can essentially move only in a lifting direction, and additionally, the deflection lever runs essentially parallel in the cover. The lever arm has a jointed connection to the cover with its upper end that is turned towards the support unit, and it can be engaged in the running slots with its opposite bottom end. This ensures that only a one-dimensional movement of the lever arm is possible in the base module.  
           [0024]    An implementation of the tipping mechanism is as follows. To achieve a tipping and locking movement of the delivery trough, the bottom end of the deflection lever used to unlock the basic position within the dimensions of the cover can be swiveled in an initial direction of swivel. This is in a direction that is essentially vertical to the direction of lift. To achieve the tipping movement, it can move in a lifting direction, and, for locking the tipped end position, it can swivel in a second direction that is anti-parallel to the first direction of swivel.  
           [0025]    The aforementioned design makes it possible to implement completely different tipping angles and to lock the tipped position. This can be done easily, without the need to change components, if the base module and the deflection lever have cams and locating positions for the cams that correspond to each other, with the cams and the locating positions being arranged behind each other in the direction of lift.  
           [0026]    To make it easier to find the right locking position, a stop can be used to limit the tipping movement for the cover and/or the support unit. This stop can be mounted so that its height can be adjusted.  
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0027]    The novel features believed characteristic of the invention are set out in the claims below. The invention itself, however, as well as other features and advantages thereof, are best understood by reference to the detailed description, which follows, when read in conjunction with the accompanying drawing, wherein:  
         [0028]    [0028]FIG. 1 depicts a schematic representation of a first transport car belonging to a sorting conveyor, with a delivery trough in a basic position and a tipped position;  
         [0029]    [0029]FIG. 2 depicts a side view of the transport car shown in FIG. 1;  
         [0030]    [0030]FIG. 3 depicts a schematic representation of a second transport car belonging to a sorting conveyor, with a delivery trough in the basic position;  
         [0031]    [0031]FIG. 4 depicts the second transport car shown in FIG. 3, with the delivery trough in the tipped position; and  
         [0032]    [0032]FIG. 5 depicts a schematic representation of a third transport car of a sorting conveyor, with a delivery trough in the tipped position. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0033]    In FIGS.  1  to  5 , the same reference characters are used for parts that are structurally similar or identical. When parts are structurally similar or identical, those in the tipped position are marked with an apostrophe (+) to distinguish them from the components in the basic position.  
         [0034]    [0034]FIG. 1 shows a schematic representation of a first transport car  2 , which is part of a revolving chain of transport cars belonging to a sorting conveyor (not shown in further detail). A direction of travel of the sorting conveyor runs vertically to the plane of the diagram. The transport car  2  has a delivery trough  6 ,  6 ′ mounted on a support unit  4 ,  4 ′ for holding items of package freight, which are not shown here. The support unit  4 ,  4 ′ can swivel round an axis  8  parallel to the direction of travel. In the figure, it is shown tipped to the right.  
         [0035]    The support unit  4  with cam-shaped pins  10 ,  10 ′, is depicted initially engaging with the deflection in an arc-shaped guide rail  12  which is molded in a base module  14 . The base module  14  therefore serves to carry the support unit  4 , and it represents a connection with the drive elements of the sorting conveyor that are not shown here such as, for example, linear motors—and the neighboring transport cars.  
         [0036]    In the base module  14 , there are also lever arms  16 ,  16 ′. In the present example embodiment, the lever arm  16 ′ on the left-hand side has caused the delivery trough  6  to tip by means of a lifting movement  18 . In the base module  14 , guide rails  20 ,  22  with the associated pins  24 ,  24 ′ or  26 ,  26 ′ which are disposed on the lever arms  16 ,  16 ′ are likewise provided to guide the lever arms  16 ,  16 ′.  
         [0037]    So that a delivery trough  6 ,  6 ′ can be tipped to one side, provision is made for the lever arm on the other side—in this case the lever arm  6 ′—to engage in the running slots  28 ,  28 ′. In the present example embodiment, these specify only a two-dimensional curve in the space that the lever arm  16 ′ has to follow. To engage lever arm  16 ′ in the running slot  28 ,  28 ′, the lever arms  16 ,  16 ′ have a friction bearing mounted cam follower roller  30 ,  30 ′, which is engaged in the running slot  28 ,  28 ′ by means of an engaging element (not shown).  
         [0038]    So that the lever arm  16 ′ can, however, carry out the lifting movement  18 , the lever arm  16 ′ must first be unlocked. The locking includes the fact that roller bearing mounted pin  26 ′ is placed in the parked position in the first projection  32 , which is to the side of the guide rail  22  and is part of the guide rail  22 , and it is swiveled by means of a deflection roller  34  in an initial direction of swivel  36 . The deflection roller  34  could therefore be dispensed with, because, with an appropriately designed engaging element, the function of deflection roller  34  could be achieved by direct contact with the cam follower roller. The first direction of swivel  36  is essentially vertical to the lifting movement  18 . The first swiveling movement is around the axis of the pin  24 ′. This is followed by the lifting movement  18 , with the tipping of the support unit  4 ′ and of the delivery trough  6 ′. This tipping movement is depicted. Finally, to lock the tipped position, a movement takes place in a second direction of swivel  38 , which is anti-parallel to the first direction of swivel  36 . The roller bearing mounted pin  26 ′ then rests in a second projection  40  laterally at the end of the vertically inclined section of the guide rail  22 , and it can no longer be pressed directly either upwards or downwards. This ensures that the delivery trough  6 ′ is maintained permanently in the tipped position until the transport car  2  passes a reset running slot (not shown) and a reverse sequence of the movement of the lever arm  16 ′ takes place.  
         [0039]    The transfer of the lifting movement  18  from the lever arm  16 ′ to the support unit  4 ′ is achieved by a slide seating of the lever arm  16 ′ at an abutment of the support unit  4 ′. This ensures that the other lever arm  16  is also not moved. The amount of space required downwards is therefore much less than in the case of a lever arm that swivels downwards. In addition, the support unit  4 ′ is swiveled at the same time as the lifting movement  18  starts, so that a lifting movement of the lever arm  16  is blocked. Because of the length of the guide rails  20 ,  22  and the arc-shaped section of the guide rail  12 , the required tipping angles can also be set within broad limits. The support unit  4 ,  4 ′ and the lever arms  16 ,  16 ′ can remain unchanged.  
         [0040]    [0040]FIG. 2 depicts a side view of the transport car  2 . In this view, it is particularly clear that the base module  14  has two parts, namely  14   a  and  14   b , which are mirror images of one another. In this way, the support unit  4  and the lever arms  16  are particularly well engaged in the internal guide rails  12 ,  20 , and  22 .  
         [0041]    [0041]FIG. 3 shows a second transport car  42  belonging to a sorting conveyor which is not shown further here. In this case as well provision is made for a support unit  46  that carries the delivery trough  44  and which can rotate around the axis  48 . The support unit  46  and the lever arms  50 ,  50 ′ are in turn held in a base module  54 . To guide the lever arms  50 ,  50 ′, the guide rails  56 ,  58  are likewise provided in a base module  54 , with the guide rails  56  having two projections  60  and  62 . The top projection  62  is used for locking the basic position of the delivery trough  44 . Likewise, the bottom projection  60  is used for locking the tipped position, as shown in FIG. 4. The lever arms  50 ,  50 ′ have in addition cam-shaped pins  64 ,  66 , by means of which guiding is achieved in the guide rails  56  and  58 .  
         [0042]    As depicted in FIG. 4, the difference between this example embodiment and the previous example embodiment shown in FIGS. 1 and 2 is that that the support unit  46  is not pushed upwards by a pushing movement (lifting movement  18 ), but is instead drawn downwards by a pulling movement (lifting movement  65 ). The remaining procedure for unlocking and locking the two positions of the delivery trough  44  has therefore been adopted in this example embodiment. As set out above, a movement of the swivel arm  50 ′ on its cam follower roller  30 ′, which can be engaged in the running slot  28 ′, is provided here in the first and second direction of swivel  36  or  38 , as the case may be. Even in the case of this example embodiment, only one of the two lever arms  50 ,  50 ′ is moved to produce the tipping movement.  
         [0043]    [0043]FIG. 5 depicted a third transport car  68 . In contrast to the previous example embodiments, a two-part lever arm  70  with a modified functional mechanism is used here. All the other functional mechanisms follow the principles set out above with respect to the two previous example embodiments.  
         [0044]    The lever arm  70  has a cover  72  and a swivel rod  74 . The cover  72  engages a slide seating on a support unit  76 ′ for the delivery trough  6 ,  6 ′, and it can essentially only be moved in the lifting direction  18 . The swivel rod  74  is disposed running in the cover  72 . The top end facing the support unit  76  can be rotated in a bearing  79 . It is connected to the cover  72 . The opposite bottom end with the cam follower roller  30  can be engaged in the running slot  28 ,  28 ′.  
         [0045]    In the present example embodiment, the tipping and locking movement of the delivery trough  6 ,  6 ′ is achieved by swiveling the bottom end of the swivel rod  74  for releasing the locked basic position within the dimensions of the cover  72  in the first direction of swivel  36 . Through this swiveling movement, the roller bearing mounted pin  26 ,  26 ′ is moved out of the first projection  80  belonging laterally to the vertical guide rail  78 , and is then moved, together with the cover element  72 , in the lifting direction  18  in order to bring about the tipping movement. To lock the tipped end position, the swivel rod  74  is swiveled in the second direction of swivel  38 —which is anti-parallel to the first direction of swivel  36 —into a second projection  82 .  
         [0046]    A special feature of this example embodiment is that the tipping angle that can be achieved can be variable adjustments within certain limits. For this purpose, a base module  84 , which carries the cover  72  and the support unit  76 , and the swivel rod  74 , have cams  86  and locating positions  88  for the cams  86  corresponding to each other, with the cams  86  and the locating positions  88  being behind each other in the lifting direction  18 .  
         [0047]    To make it easier to find the required position of cams  86  and the locating positions  88  relative to each other—which can be sensitive because of the comparatively fine grid—a stop  90  is provided to limit the tipping movement for the support unit  76 . This stop  90  is implemented in the present embodiment as a part that can be inserted in the guide rail  12 , in which the support unit  76  is engaged with its pins  10 . Alternatively, stop  90  can also be provided for the cover  72  to limit its lifting movement  18 . This would have the additional advantage that, with a stop  90  that could be adjusted for height, the maximum tipping angle could be set from outside. Another possible alternative is to have the delivery trough come up against a stop during the tipping movement. The position of this stop could in turn be set, such as, for example, by means of a running slot. This means that, within a sorting conveyor with one and the same transport car, different tipping angles can be implemented to suit the prevailing requirements.  
         [0048]    The invention being thus described, it will be obvious that the same may be varied in many ways. The variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.