Abstract:
An apparatus and method producing a plait-like portion on a tubular packaging casing, which accommodates a filling material includes a plait-like portion at least approximately free of filling material, extending along a longitudinal plait-axis. The apparatus comprises a first displacer unit with a first pair of displacer elements reversibly movable between an opened and a closed position perpendicular to the longitudinal plait-axis. A displacer clearance is created between the first pair of displacer elements, which surrounds the longitudinal plait-axis, in which the tubular packaging casing is being gathered, when the first pair of displacer elements is in the closed position. The apparatus comprises a second displacer unit with a second pair of displacer elements also being reversibly movable between an opened and a closed position perpendicular to the longitudinal plait-axis. A displacer clearance is created between the second pair of displacer elements, similar to first pair of displacer elements.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This patent application claims priority to and the benefit of European patent application EP 09 015 524.3-1260, filed Dec. 15, 2009, which is hereby incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     The present invention relates to an apparatus and a method for producing a plait-like portion on a tubular packaging casing according to the preamble of independent claims  1  and  10 . 
     In particular, the invention concerns an apparatus for producing a plait-like portion on a tubular packaging casing which accommodates a filling material in particular sausage meat, wherein the plait-like portion is at least approximately free of filling material and comprises along a longitudinal plait-axis. The apparatus comprises a first displacer unit with a first pair of displacer elements being reversibly movable perpendicular to the longitudinal plait-axis between an opened and a closed position. A displacer clearance is being created between the first pair of displacer elements, which surrounds the longitudinal plait-axis and in which the tubular packaging casing is being gathered, when the first pair of displacer elements is in the closed position. Beyond that, the apparatus comprises a second displacer unit with a second pair of displacer elements also being reversibly movable perpendicular to the longitudinal plait-axis between an opened and a closed position. Again, a displacer clearance is being created between the second pair of displacer elements, which surrounds the longitudinal plait-axis and in which the tubular packaging casing is being gathered, when the second pair of displacer elements is in the closed position. The second displacer unit is reversibly movable parallel to the longitudinal plait-axis between a narrow position in which the first displacer unit is adjacent to the second displacer unit, and a spread position in which the second displacer unit is moved away from the first displacer unit. Furthermore, the apparatus comprises a first drive unit for the movement of the first and second pair of displacer elements between the opened and closed position. The first drive unit comprises an adjustment device rotatable around a pivot axis essentially parallel to the longitudinal plait-axis. 
     Moreover, the invention concerns method for producing a plait-like portion on a tubular packaging casing which accommodates a filling material in particular sausage meat, wherein the plait-like portion is at least approximately free of filling material and extends along a longitudinal plait-axis. The method includes the steps of conveying of a filling material into a tubular packaging casing and constricting the filled tubular packaging casing by moving a first pair of displacer elements of a first displacer unit and a second pair of displacer elements of a second displacer unit from an opened into a closed position by means of a first drive unit. Furthermore, a displacer clearance is created between the first and second pair of displacer elements surrounding the longitudinal plait-axis, in which the tubular packaging casing is being gathered when the first and second pair of displacer elements are in the closed position. Thereafter, a plait-like portion is produced by moving the second displacer unit parallel to the longitudinal plait-axis away from a narrow position in which the second displacer unit is adjacent to the first displacer unit, into a spread position in which the second displacer unit is away from the first displacer unit. 
     It is the usual practice in sausage production, to use for example automatic clipping machines for filling e.g. sausage meat via a filling tube into a flexible packaging material, like a tubular casing which is closed by a closure means, referred to as closing clip, at the first end. After the filling operation is concluded, a gathered plait-like portion, which is free of filling material, is formed by two displacer units. Two more clips are then applied to that plait-like portion, a first closing clip in order to close the second end of the filled packaging material and a second closing clip in order to close the first end of the subsequent sausage product. Thereafter, said plait-like portion is severed between said two clips creating one complete sausage product and packaging material closed at its first end to be filled, in order to form the next sausage product. Such a practice for producing sausages is disclosed, for example, by EP-patent application 1 967 073 A1 or DE-Utility model 20 2006 012 324 U1. 
     After the filling process, the sausage products can be sometimes subjected to further processing, for example in a smoking chamber or they are just being packed in a box for shipping. 
     The different sausage products are typically characterized by a number of parameters, such as caliber (i.e. the actual diameter of the sausage product), overall length, specific type of the filling material as well as packaging casing material etc. Also, it is possible to vary the density of the filling material, in order to produce loosely filled or tightly filled sausage products, by injecting more or less filling material into the casing. However, in case of a tightly filled sausage product, these sausage products are rather prone to damages on the casing, due to the high pressure inside the sausage product and the often thin and sensitive casing material. Impacts, falls and other kinds of careless handling can result inevitable in notable damages to the sausage products, which lead to outcast and unnecessary costs. A particular problem in this context constitutes within the actual procedure of constricting the casing by means of the two displacer units and forming the plait-like portion out of the tubular packaging casing. Depending on the above mentioned parameters, in particular, sensitive casing material or “normal” casing material which is filled with sausage meat at high pressure may be damaged during the constricting process when executed at a “normal” speed. Moreover, the casing material may be also damaged during forming the plait-like portion. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is to solve the above described problem. In particular, it is the object of the present invention to provide an apparatus according to independent claim  1  and a method according to independent claim  10  for producing a plait-like portion on a tubular packaging casing, with which the risk of damaging the casing material while constricting said material and forming a plait-like portion will be reduced and the productivity in the production of sausage like products is raised. 
     What is proposed, in particular, is an apparatus for producing a plait-like portion on a tubular packaging casing which accommodates a filling material in particular sausage meat, wherein the plait-like portion is at least approximately free of filling material and comprises a longitudinal plait-axis. The apparatus comprises a first displacer unit with a first pair of displacer elements being reversibly movable perpendicular to the longitudinal plait-axis between an opened and a closed position. A displacer clearance is being created between the first pair of displacer elements, which surrounds the longitudinal plait-axis, in which the tubular packaging casing is being gathered, when the first pair of displacer elements is in the closed position. Beyond that, the apparatus comprises a second displacer unit with a second pair of displacer elements also being reversibly movable perpendicular to the longitudinal plait-axis between an opened and a closed position. Again, a displacer clearance is being created between the second pair of displacer elements, which surrounds the longitudinal plait-axis, in which the tubular packaging casing is being gathered, when the second pair of displacer elements is in the closed position. The second pair of displacer elements is reversibly movable parallel to the longitudinal plait-axis between a narrow position in which the first displacer unit is adjacent to the second displacer unit, and a spread position in which the second displacer unit is moved away from the first displacer unit. Furthermore, the apparatus comprises a first drive unit for the movement of the first and second pair of displacer elements between the opened and closed position. The first drive unit comprises an adjustment device rotatable around a pivot axis essentially parallel to the longitudinal plait-axis. 
     According to the present invention, it is proposed that the pivot axis of the adjustment device is adjustable for changing the size of the displacer clearance created by the first and second pair of displacer elements. Adapting the size of the displacer clearance depending on the cross-section area of the plait-like portion optimizes the voiding of the filling material from the plait-like portion. 
     Also, adapting the size of the displacer clearance depending on e.g. the sensitivity of casing material or the caliber of the sausage product to be produced, reduces the risk of damaging while gathering the casing material and forming the plait-like portion. 
     It is advantageous that the adjustment device comprises a drive element and a two-armed lever which are coupled to each other by a torque transmission element in order to transmit the motion of the drive mechanism via a drive arm to the displacer units. The transmission of the motion from a drive mechanism to the displacer units can alternatively be done by a chain-drive, gear-drive, belt-drive or any other possible means of transmission. The torque transmission element can be in form of a sliding block or likewise, to permit the drive element and the two-armed lever to be shifted relative to each other while allowing a continuously transmission of torque. In order to support this, it is also favorably that the torque transmission element is attached to the two-armed lever and is extending into a radial aligned guide being part of the drive element, to allow the torque transmission element to continuously transmit torque from the drive element to the two-armed lever, even if the two-armed lever varies its position relative to the drive element. 
     To allow a variation of the position of the two-armed lever relative to the drive element, it is possible that the adjustment device comprises a bushing with an eccentric portion and a centric portion, in order to provide two centers of rotation for the bushing. In this configuration, the two-armed lever is mounted onto the eccentric portion of the bushing, to allow the pivot axis of the two-armed lever to orbit around the pivot axis of the drive element. 
     In order to facilitate the adjustment of the position of the bushing, in a preferred embodiment the adjustment device comprises a locking ring with an eccentric adapter firmly connected onto the bushing. 
     A second drive unit can be provided to the apparatus for driving the adjustment device in a rotational motion. The second drive unit may be formed by a linear actuator, in order to convert rotary into linear motion. However, it is also possible that the second drive is in form of other kinds of motors. It is further advantageous, that the second drive unit comprises a lead screw with a lead screw nut, for the purpose of providing a purchase for leading off the motion of the drive unit. 
     With the aim of transmitting the linear motion of the drive unit onto the adjustment device, the second drive unit advantageously comprises a drive rod connecting the lead screw nut with the locking ring. It is also possible that the second drive unit is transmitting its actuation by other means, such as a gear-, belt-drive or other appropriate gears. Alternatively, the second drive unit can directly be mounted on the adjustment device. 
     With the purpose of control and adjust their actuation, it is further advantageous that a control unit is linked to the first and second drive units. In this case, the adjustment device may automatically be actuated on the basis of data regarding the sausage products actually to be produced. 
     It is the further object of the present invention to solve the above described problem by providing a method according to independent claim  12  of the present. In particular, a method is provided for producing a plait-like portion on a tubular packaging casing which accommodates a filling material in particular sausage meat, wherein the plait-like portion is at least approximately free of filling material and comprises along a longitudinal plait-axis. The method comprises the steps of conveying of a filling material into a tubular packaging casing and constricting the filled tubular packaging casing by moving a first pair of displacer elements of a first displacer unit and a second pair of displacer elements of a second displacer unit from an opened into a closed position by means of a first drive unit. Furthermore, a displacer clearance is created between the first and second pair of displacer elements surrounding the longitudinal plait-axis, in which the tubular packaging casing is being gathered when the first and second pair of displacer elements are in the closed position, and a plait-like portion is produced by moving the second displacer unit parallel to the longitudinal plait-axis away from a narrow position in which the second displacer unit is adjacent to the first displacer unit, into a spread position in which the second displacer unit is away from the first displacer unit. 
     In accordance with the present invention, the method further comprises the step of changing the size of the displacer clearance created by the first and second pair of displacer elements by adjusting a pivot axis of an adjustment device. By changing the size of the displacer clearance, the risk of damaging in particular sensitive casing material may be reduced. Moreover, an adaption may be made to the caliber of the sausage-like product to be produced e.g., in case of a larger caliber of the sausage product, to the additional casing material forming a plait-like portion of a respectively larger diameter. 
     The method further comprises the step of putting parameter of a pre-selected product, which is to be produced, into a control unit controlling the adjustment device, from which in a preferred embodiment a signal corresponding to the parameter of the pre-selected product is transmitted from the control unit to the second drive unit driving the adjustment device. Thereafter, in accordance with the signal transmitted to the second drive unit corresponding to the parameter of the pre-selected product, a bushing of the adjustment device is positioned. 
     The above mentioned features of the inventive method allow an automatically adjustment of the adjustment device on the basis of data regarding pre-selected products. The adjustment of the size of the displacer clearance by means of the adjustment device may even be done during on-going production without having to stop the sausage-product manufacturing process. Thereby, the sausage production may be improved and increased. In particular, the voiding of the filling material from the plait-like portion will be optimized. Moreover, the risk of damaging the casing material will be minimized while maintaining a constant or higher production rate. 
     Other advantages and one embodiment of the present invention shall now be described with reference to the attached drawings. The term “top”, “bottom”, “left” and “right” used when describing the embodiment relate to the drawings orientated in such a way that the reference numerals and name of the figures can be read normally. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       In the drawings, 
         FIG. 1  shows a front view of the inventive apparatus; 
         FIG. 2  shows a side view of the inventive apparatus according to  FIG. 1 ; 
         FIG. 3  shows a detailed view of the inventive adjustment device with a drive element in front of a two-armed lever coupled by a torque transmission element; 
         FIG. 4  shows a detailed view on a two-armed lever together with upper and lower connecting rods; and 
         FIG. 5  shows a section view according to section C-C of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The embodiment of the inventive apparatus described in the following is used within clipping machines for the production of sausage products. The inventive apparatus may also be used, of course, in production of sausage-shaped products that are not foodstuffs, but for example, sealing compounds or adhesives. 
       FIG. 1  shows a schematic front view of the inventive apparatus according to a preferred embodiment in perspective direction perpendicular to a longitudinal plait-axis  77 , together with first and second drive units  10 ,  90 , a first displacer unit  50   a  having a first pair of displacer elements  60   a  and a second displacer unit  50   b  having a second pair of displacer elements  60   b . The first and second displacer units  50   a ,  50   b  are actuated by the first drive unit  10  for a reversible movement perpendicular to the plait-axis  77  along vertical displacer guide rods.  FIG. 1  shows only the first displacer guide rod  72  along which the first pair of displacer elements  60   a  is vertically slidable. The apparatus according to the present invention comprises an adjustment device  20  as well as a second drive unit  90  actuating the adjustment device  20 . 
       FIG. 2  shows a schematic side view of the inventive apparatus according to a preferred embodiment in perspective direction of the longitudinal plait-axis  77 , together with first and second drive units  10 ,  90  and first and second displacer units  50   a ,  50   b  actuated by the first drive unit  10 . 
       FIG. 2  shows a first displacer unit  50   a  together with upper and lower displacer elements  62   a ,  62   b . The upper and lower displacer elements  62   a ,  62   b  are connected by upper and lower displacer element supporters  66 ,  68  onto upper and lower displacer guide sleeves  74   a ,  74   b , which are slidable along the displacer guide rod  72 . 
     In  FIG. 2 , the upper and lower displacer elements  62   a ,  62   b  are in the closed position. That means, the upper displacer element  62   a  is in its lowest position, whereas the lower displacer element  62   b  is in its upper most position. In the closed position, the upper and lower displacer elements  62   a ,  62   b  form a displacer clearance  78 . 
     The upper displacer guide sleeve  74   a  can be slided from its current position as shown in  FIG. 2 , further upwards, in order to move the upper displacer element  62   a  into the opened position, whereas the lower displacer guide sleeve  74   b  can be slided from its current position further downwards, in order to move the upper displacer elements  62   b  into the opened position. The first displacer unit  50   a  is in the opened position, when the upper displacer element  62   a  of the first displacer unit  50   a  is in a maximum linear displacement to the lower displacer element  64   a.    
       FIG. 1  and  FIG. 2  further show the first drive unit  10  comprises a drive arm  12  in form of a longitudinal lever  16  with a gear wheel section  15  at its end pointing towards the adjustment device  20 . The other end of the lever  16  (not shown) is mounted onto a drive (not shown) of the first drive unit  10  for pivotal driving the drive arm  12 . 
     The adjustment device  20  comprises a drive element  30 , a two-armed lever  40 , a bushing  25 , a torque transmission element  24  and a locking ring  80 . 
     The drive element  30  is in form of a flat circular disc with a gear wheel section  31  located on its outer edge and two drive element guide arms in form of a left-hand and right-hand longitudinal bars  34   a ,  34   b  defining a radial aligned notch  35  between them, as illustrated more particularly in  FIG. 3 . 
     As it can be inferred from  FIG. 4 , the two-armed lever  40  comprises a flat longitudinal panel  43  with a round centre hole  41 , a two-armed lever attachment  46  formed by an eccentric belly, and two adapters  42   a ,  42   b  in form of arms. A bolt  44  in form of a cylindrical shaft orientated parallel to the longitudinal plait axis  77  is firmly fitted with one end to the two-armed lever attachment  46 . The two adapters  42   a ,  42   b  are symmetrical to a plane running through the centre of the two-armed lever  40  parallel to the plait-axis  77 , and fitted with holes extending parallel the plait-axis  77  at each ends. The two adapters  42   a ,  42   b  are connected by pins  48   a ,  48   b  to first ends of longitudinal connecting rods  45   a ,  45   b , which are positioned with their middle centre line  47  perpendicular to the plait axis  77  (see also  FIGS. 3 and 5 ). The second ends of the longitudinal connecting rods  45   a ,  45   b  are connected via upper and lower guide sleeve adapter pins  76   a ,  76   b  to the displacer guide sleeves  74   a ,  74   b . The displacer guide sleeves  74   a ,  74   b  are slidably fitted around displacer guide rods  72 , arranged perpendicularly to the plait-axis  77  in a vertical orientation, in order to slide up and down the displacer guide rods  72 . 
     The torque transmission element  24  is formed by a sliding block with a square cross-section fitted between the left-hand and right-hand longitudinal bars  34   a ,  34   b  within the notch  35  of the drive element  30 . The sliding block  24  comprises a centre hole through which the two-armed lever bolt  44  is fitted (see also  FIG. 3  and  FIG. 5 ). 
     Drive element  30  and two-armed lever  40  are positioned on a drive unit shaft  22 . Drive unit shaft  22  thereby extends through centre holes  37 ,  41  of drive element  30  and two-armed lever  40 . Drive unit shaft  22  is firmly coupled with its right-hand side end, as shown in  FIG. 5 , to displacer guide rod  72 , in a horizontal orientation, parallel to plait axis  77 . 
     Drive arm  12  of the first drive unit  10  is connected to the adjustment device  20  by its gear wheel section  15  engaging the gear wheel section  31  of the drive element  30 , in order to transmit the torque created by the first drive unit  10  to the drive element  30 . 
     The torque of drive element  30 , received by the drive arm  12 , is transmitted onto the two-armed lever  40  by the torque transmission element  24 . 
     As illustrated in  FIG. 5 , the drive element  30  is arranged in front of the two-armed lever  40  that means to the left-hand side of the two-armed lever  40 . As it can be further inferred from  FIG. 5 , a bushing  25  is positioned onto the drive unit shaft  22  having an inner diameter corresponding to the outer diameter of drive unit shaft  22 . The bushing  25  extends through the centre hole  37  of drive element  30  and the centre hole  41  of the two-armed lever  40 . Bushing  25  comprises a centric portion  27  and an eccentric portion  29 , which are both formed as cylinders and positioned in their longitudinal direction offset to each other. The drive element  30  is fitted onto the centric portion  27  of the bushing  25  and the two-armed lever  40  is positioned onto the eccentric portion  29  of the bushing  25 . The centric portion  27  has a pivot axis  36  and the eccentric portion has a pivot axis  47 . Due to the off-centre alignment of the centric portion  27  and the eccentric portion  29 , the pivot axis  36  is not identical to the pivot axis  47 . A bearing is positioned between the centric portion  27  and the drive element  30  to reduce friction between bushing  25  and drive element  30  during pivotal movement of drive element  30  about the centric portion  27  of bushing  25 . The centre line of the centric portion  27  as well as the centre line of the eccentric portion  29  are both parallel to the plait axis  77 . 
     The locking ring  80  is firmly attached around the front end of centric portion  27  of the bushing subjecting from drive element  30 . A locking ring cover disc  81  is attached to the left-hand side end of the drive unit shaft  22  by means of a locking ring screw  86 , covering the front end of the centric portion  27  of the bushing  25  (see  FIGS. 1 and 5 ). 
       FIG. 2  shows the second drive unit  90  comprises a motor  92 , a longitudinal lead screw  100  and a drive rod  108 . 
     The motor  92 , according to the present embodiment, is in form of an electric motor, which is attached to a frame element (not shown) and which comprises a drive shaft (also not shown). A gear drive  93  is connected to the upper end of the drive shaft of the motor  92 . 
     The lead screw  100  comprises a lead screw gear  95  at its upper end pointing away from the adjustment device  20 . The centre line  101  of the lead screw  100  extends perpendicular to the plait axis  77  and parallel to the drive shaft of the motor  92 . A lead screw nut  102  having with a round lead screw nut adapter  104  is fitted onto the lead screw  100 . A roller chain  94  is connecting the gear drive  93  with the lead screw gear  95 . 
     Left-hand and right-hand lead screw guide rods  106   a ,  106   b  are arranged parallel to lead screw  100 , one on the left-hand side and one on the right-hand side of the lead screw  100 , as it can be inferred from  FIG. 2 . Lead screw nut  102 , which is driven along the lead screw  100 , comprises extensions on its left- and right-hand sides forming sleeves  103  for engaging left-hand and right-hand lead screw guide rods  106   a ,  106   b.    
     Drive rod  108  comprises a longitudinal drive rod shaft  107  with circular upper and lower drive rod adapters  105   a ,  105   b . Drive rod  108  is orientated with its centre line  109  perpendicular to the plait axis  77 . The upper drive rod adapter  105   a  is pivotal connected to the lead screw nut adapter  104  and the lower drive rod adapter  105   b  is pivotal connected to the locking ring adapter  82  of locking ring  80 . 
     The present inventive apparatus also comprises a control unit  110  (schematically shown in  FIG. 2 ). The control unit  110  is connected to the first drive unit  10  and second drive unit  90 , in order to feed information into them and to control the actuation of the drive units  10 ,  90 . It is also possible that one control unit is connected to the first drive unit  10  and a separate control unit is connected to the second drive unit  90 , and that these two control units are being linked to each other to cross function. 
     When the drive arm  12  is being put into a pivotal motion by the first drive unit  10 , the drive arm  12  is moved reversibly from side to side in a given frequency. The torque created by the drive arm  12  is being transmitted onto the drive element  30  by means of the gear drive  14 , as the gear wheel section  15  of the drive arm  12  is engaging the gear wheel section  31  of the drive element  30 . Due to the transmitted torque to the drive element  30 , the drive element  30  is pivotally rotating about a given amount reversibly into clockwise and anti-clockwise direction about pivot axis  36 . The torque of drive element  30  is being transmitted by means of the torque transmission element  24  to the two-armed lever  40 , left-hand or right-hand longitudinal bars  34   a ,  34   b  onto the square cross sectioned sliding block. The received torque is further transmitted via the two armed lever bolt  44  onto the two-armed lever  40  for rotating the two-armed lever  40  about a given amount reversibly into clockwise and anti-clockwise direction. By rotating the two-armed lever  40  two-armed lever adapter  42   a  is being pushed either upwards or downwards perpendicular to the plait-axis  77 . In the same way, but in opposite direction to the up and down movement of two-armed lever adapter  42   a , is two-armed lever adapter  42   b  is being pushed either up or down perpendicular to the plait-axis  77 . As the left-hand and the right-hand two-armed lever adapters  42   a ,  42   b  are being pushed either upwards and/or downwards perpendicular to the plait axis  77 , the upper and lower displacer guide sleeves  74   a ,  74   b  are also being pushed either upwards and/or downwards along the displacer guide rod  72  by upper and lower connecting rods  45   a ,  45   b  connecting two-armed lever adapter  42   a ,  42   b  to upper and lower displacer guide sleeves  74   a ,  74   b . By moving the upper and lower displacer guide sleeves  74   a ,  74   b  up and down along the displacer guide rod  72 , the upper and lower displacer elements  62   a ,  62   b ,  64   a ,  64   b  are also being reversibly moved between their opened and closed position, as they are respectively connected to the upper and lower displacer guide sleeves  74   a ,  74   b  by means of the upper and lower displacer element supporters  66 ,  68 . 
     By feeding the relevant information regarding the parameter of the to-be-produced sausage product into the control unit  110 , which is connected to the second drive unit  90 , the drive shaft (also not shown) of the motor  92  is being turned about a pre-determined amount in respect to the parameter of the to-be-produced sausage product. The drive gear  93  is being turned, as it is connected to the driveshaft of the motor  92 . The rotational motion of the drive gear  93  is being transmitted via roller chain  94  onto lead screw gear  95 . The rotational motion of the lead screw gear  95  is transmitted onto lead screw  100 , causing the lead screw nut  102  to travel either upwards (i.e. away from the adjustment device  20 ) or downwards (i.e. towards the adjustment device  20 ) along the lead screw  100 . Left-hand and right-hand lead screw guide rods  106   a ,  106   b  on each side and parallel to the lead screw are preventing the lead screw nut  102  from rotating around the lead screw  100 , as the lead screw nut sleeves  103  are slidably engaging the left-hand and right-hand lead screw guide rods  106   a ,  106   b . Since the lead screw nut adapter  104  is connected to the upper drive rod adapter  105   a , the drive rod  108  is pushed in the same direction as the lead screw nut  102 . The lower drive rod adapter  105   b  is turning the locking ring adapter  82 , depending on the upwards or downwards direction of the drive rod  108 , either clockwise or anti-clockwise direction. The locking ring  80  is transmitting its received torque from the drive rod  108  via centric portion  27  onto the eccentric portion  29  of the bushing  25 , causing pivot axis  47  of two-armed lever  40  to be moved along a circle about pivot axis  36  of drive element  30 . The amount of the movement of the pivot axis  47  corresponds to the amount of the movement of locking ring  80 . 
     As the pivot axis  47  of two-armed lever  40  is being moved about a predetermined amount, the position of two-armed lever  40  has been changed relative to drive unit shaft  22  and to drive element  30 , respectively. Thus, the upper and lower displacer elements  62   a ,  62   b ,  64   a ,  64   b  are pushed respectively upwards and downwards in the direction perpendicular to the plait axis  77 , since they are connected via the upper and lower displacer element supporters  66 ,  68  and the upper and lower connecting rods  45   a ,  45   b  to the left-hand and right-hand two-armed lever adapters  42   a ,  42   b.    
     Since, the drive element  30  rests slidable on the centric portion  27  of the bushing  29 , the pivot axis  36  of drive element  30  is not being moved and stays stationary relative to drive unit shaft  22 , as the locking ring  80  is applying a torque onto the eccentric portion  29  of the bushing  25 , in order to move the pivot axis  47  of two-armed lever  40 . 
     Also, as the torque transmission element  24  is in form of a square cross sectioned sliding block and being positioned within the notch  35  between the two drive element guide arms  34   a ,  34   b  of the drive element guide notch  35 , the torque transmission element  24  is able to compensate the relative movement of the drive element  30  to the two-armed lever  40  and allows a reliable transmission of torque between drive element  30  and two-armed lever  40 . 
     By moving the pivot axis  47  of the two-armed lever  40  relative to the pivot axis  36  of drive element  30 , caused by adjusting bushing  25 , two-armed lever  40  is also pivoted in its position relative to drive element  30 . During this adjustment, the closed position as well as the opened position of the upper and lower displacer elements  62   a ,  62   b ,  64   a ,  64   b  are changed accordingly. The amount of which the two-armed lever  40  is being moved is directly proportional to the amount of which the opened and closed position of the upper and lower displacer elements  62   a ,  62   b ,  64   a ,  64   b  are being changed. In the case of changing the closed position of the upper and lower displacer elements  62   a ,  62   b ,  64   a ,  64   b  about a pre-determined amount, the displacer clearance  77  is being changed about an amount relative and in proportion to that amount of the change of the closed position of the upper and lower displacer elements  62   a ,  62   b ,  64   a ,  64   b.    
     In other words, by adjusting the position of the bushing  25 , in particular the eccentric portion  29  of bushing  25 , an adjustment of the opened and closed position of the displacer elements  62   a ,  62   b ,  64   a ,  64   b  can be done as well as an adjustment of the diameter of the displacer clearance  77 . 
     Thereby, it is possible to easily adapt the displacer clearance  77  according to the respective parameters of the to-be produced sausage products. The adjustment of the size of the displacer clearance  77  may even be done during the on-going production without having to stop the sausage-product manufacturing process. The displacer clearance  77  can be increased, if, for example, a sausage product with a larger diameter, a thicker tubular packaging casing or a more rigid and dense filling material is to be produced, in order to create an appropriate plait-like portion on a tubular packaging casing in respect to the cross-section area of the plait-like portion and without damaging the sausage product. It is thereby possible to start-up the production process of the sausage products according to the pre-selected production parameters and to change the size of the displacer clearance  77  during the production process, in order to adapt or fine-tune the size of the displacer clearance  77  to the actual or changing production requirements. 
     LIST OF REFERENCES 
     
         
           1  Apparatus 
           10  First drive unit 
           12  Drive arm 
           13  Free end of drive arm 
           14  Gear drive 
           15  Gear wheel section 
           16  Longitudinal lever 
           20  Adjustment device 
           22  Drive unit shaft 
           24  Torque transmission block 
           25  Bushing 
           27  Centric portion of the bushing 
           29  Eccentric portion of the bushing 
           30  Drive element 
           31  Gear wheel section 
           32  Drive element guide 
           33  Disc 
           34   a  Left-hand drive element guide arm 
           34   b  Right-hand drive element guide arm 
           35  Notch 
           26  Pivot axis of centric portion  30   
           37  Centre hole 
           40  Two-armed lever 
           41  Centre hole 
           42   a  Left-hand two-armed lever adapter 
           42   b  Right-hand two-armed lever adapter 
           43  Panel 
           44  Two-armed lever bolt 
           45   a  Upper connecting rod 
           45   b  Lower connecting rod 
           46  Two-armed lever attachment 
           47  Pivot axis of eccentric portion  40   
           48   a  Left-hand connecting pin 
           48   b  Right-hand connecting pin 
           50   a  First Displacer unit 
           50   b  Second Displacer unit 
           60   a  First pair of displacer elements 
           60   b  Second pair of displacer elements 
           62   a  Upper displacer element of first displacer unit 
           62   b  Lower displacer element of first displacer unit 
           64   a  Upper displacer element of second displacer unit 
           64   b  Lower displacer element of second displacer unit 
           64  Lower displacer element 
           66  Upper displacer element supporter 
           68  Lower displacer element supporter 
           70  Displacer guide 
           72  Displacer guide rod 
           74   a  Upper displacer guide sleeve 
           74   b  Lower displacer guide sleeve 
           75   a  Upper displacer guide sleeve adapter 
           75   b  Lower displacer guide sleeve adapter 
           76   a  Upper displacer guide sleeve adapter pin 
           76   b  Lower displacer guide sleeve adapter pin 
           77  Longitudinal plait-axis 
           78  Displacer clearance 
           80  Locking ring 
           81  Locking ring cover disc 
           82  Locking ring adapter 
           84  Locking ring washer 
           86  Locking ring screw 
           90  Second drive unit 
           92  Motor 
           93  Drive gear of motor 
           94  Roller chain 
           95  Lead screw gear 
           100  Lead screw 
           101  Centre line of lead screw 
           102  Lead screw nut 
           103  Lead screw nut sleeve 
           104  Lead screw nut adapter 
           105   a  Upper drive rod adapter 
           105   b  Lower drive rod adapter 
           106   a  Left-hand lead screw guide rod 
           106   b  Right-hand lead screw guide rod 
           107  Drive rod shaft 
           108  Drive rod 
           109  Drive rod centre line 
           110  Control unit