Patent Description:
In various production processes, filaments or ribbons are used, e.g. when being attached to a product as a suspension element or a handle for manipulating the product. The filament or ribbon may also become part of the product or could be the product itself, like a string of adhesive, e.g. hot melt adhesive, or a plastic string processed in a 3D-printer. In all these cases, it is necessary to dispense or feed, respectively, the filament, ribbon or string with a defined speed and in predetermined lengths according to the product to be produced and/or specific process parameters.

In the following, the term "thread" is used as a representative for filaments, ribbons or any other longitudinally extending string-shaped elements or the like.

One exemplary field in which thread dispensing devices can be used, is the production of sausage-shaped products or sausages, in particular ring-shaped sausages. For producing such ring-shaped sausages, the front end of a thread is attached to the front end of a tubular casing to be filled with a filling material, by a closure clip which closes the front end of said tubular casing and which is attached via closing means. During the filling of the tubular casing, a defined length of thread is dispensed or fed, respectively. By continuing the filling of the tubular casing and holding or detaining the thread, the tubular casing forms a ring or at least a segment of a ring. After the ring-shaped sausage has reached a predefined size or form, respectively, the rear end of the filed tubular casing is gathered by gathering means and closed by a further closure clip via said closing means. The thread is caught by the gathering means and attached to the rear end of the ring-shaped sausage by said closure clip. Subsequently, the ring-shaped sausage just produced and provided with the thread connecting both ends of said sausage, is cut-off from the remaining supply of tubular casing and supply of thread, respectively.

A string or thread feeder disclosed in <CIT>, has a thread drive including two toothed wheels between which the thread is arranged for being fed, with one of the toothed wheels driven by a pneumatic actuated rocker arm. A retraction of the thread already dispensed, is enabled by an additional pneumatic piston/cylinder arrangement.

In other machines for producing sausage-shaped products, the thread is also used for closing the front end as well as the rear end of the tubular casing. In such machines, the filled tubular casing is gathered and the thread is fed to the gathered portion. A knot is formed and closed about said gathered portion.

From <CIT>, a machine for producing sausage-shaped products is known in which a thread is forwarded to the gathered portion of a filled tubular casing. The thread is fed by a motor into a closing region of the machine at which a knot is formed and tightly closed by a thread pulling mechanism.

It is an object of the present invention to provide a dispensing device and a method for dispensing thread which may be used in various applications, and which may easily be adapted to a specific application and to various process parameters. It is a further object of the present invention to provide a method and a clipping machine for producing sausage-shaped products which includes the inventive dispensing device for dispensing thread.

According to the present invention, there is provided a device for dispensing or feeding a thread in a clipping machine for producing sausage-shaped products, comprising a transport unit having at least a first and a second transport element for a defined transport of a thread, a drive unit for driving the first and second transport element and a shifting unit for reversibly shifting the first transport element relative to the second transport element.

In the inventive device for dispensing thread, or the inventive thread dispensing device, thread or a thread is transported by driving the first and second transport elements with the thread positioned there between. Thus, the transport of the thread is carried out actively. When reversibly shifting the first transport element relative to the second transport element, the thread may be inserted or removed from the thread dispensing device. Moreover, the thread transport may be started or stopped or interrupted, independently from the operation state of the drive unit, e.g. in an emergency case.

In a preferred embodiment of the inventive thread dispensing device, the first and second transport elements are at least approximately cylindrical rollers having rotation axes which are arranged parallel to each other. Moreover, the rollers have preferably and at least approximately the same diameter. This specific design enables the processing of various kinds of thread or thread material, e.g. of different diameter or cross-sectional shape or different quality. Thereby, not only thread of round cross-section may be processed, but also thread with a rectangular cross-section or ribbon. Moreover, the danger of the thread escaping from the transport unit is reduced.

It has to be noted that various kinds of material may be used for the rollers of the transport unit, like plastic or metal, e.g. dependent on the kind of thread to be treated.

Additionally, the first and second transport elements may be provided with a surface coating, e.g. rubber, for further enhancing the transportation properties.

In a further preferred embodiment of the inventive thread dispensing device, the shifting unit includes guide means for reversibly guiding the first transport element preferably in a common vertical plane away from and back to the second guide element. In preferred arrangements, the first transport element is shifted at least approximately parallel to the second transport element or is shifted along a trajectory. The guide means ensures that the transport of thread may be started or stopped without damaging the thread, namely by preventing slip between the rollers and the thread as well as preventing wear. Thereby, the reliability of the production process in which the inventive thread dispensing device is used, is improved.

Advantageously, the transportation unit is coupled to the drive unit via a gear unit. By means of the gear unit, the transportation speed may be set to a base level.

Additionally, the gear unit may be designed such that both, the first and the second transport element, are driven at identical speeds. This prevents slippage between the first and the second transport element, and thus, also slippage between one of the drive elements and the thread being transported. Thereby, a careful transport of thread is enabled, without damaging the thread.

Further advantageously, the drive unit includes a stepper motor controlled by a control unit. The use of a stepper motor allows feeding any defined length of thread. Furthermore, since the stepper motor is controlled by a control unit, different programs may be stored in said control unit, on the basis of which the stepper motor may be operated. Thus, it is possible to feed only one length of thread or more than one different lengths of thread. Also, thread may be retracted by the thread dispensing device, if necessary, and about one or more defined lengths, according to the respective program.

The control unit of the inventive thread dispensing device may be arranged at various locations. In a simple case, the control unit is integrated in the thread dispensing device. It is also possible that the control unit of the thread dispensing device is integrated in the control unit of a machine which uses the inventive thread dispensing device, like a clipping machine.

It is further possible to change the dispensing program also during the production process, e.g. during the production of two subsequent products. This allows the adaption of the production, e.g. to fluctuating features of the thread, product components, or the production machine.

For an easy and rapid change of the program of the thread dispensing device, a switch unit for selecting a predefined operation mode is provided at said device. This switch unit may be integrated in the control unit of the thread dispensing device, or may be arranged separately, for example to be reached easily by an operator. Naturally, the switch unit may also be integrated in the control unit of a machine which uses the inventive thread dispensing device, like a clipping machine.

The inventive thread dispensing device may further comprise a guide unit for guiding a thread through the dispensing device. The guide unit ensures the correct supply of thread to the transport unit of the thread dispensing device, particularly to the first and second transport element, and a defined lead out of thread from the thread dispensing device to a subsequent machine.

Additionally, the thread dispensing device may be provided with a cutting device for cutting the thread. The cutting device may be a manually operated cutting device which, in the simplest case, is a blade arranged at a frame element of the dispensing device. The cutting device allows an operator to cut-off the thread just used, e.g. at the end of the production process, or when a thread different from that presently used is selected for the further process, or to remove defective portions from the currently used thread, like weak points or knots. In a preferred embodiment, the cutting device is arranged downstream the transport unit, referred to the thread transport or feeding direction.

The shifting means for reversibly shifting the first transport element relative to the second transport element may be of any suitable construction. The shifting means may include automatic actuation means, like an additional motor that may be controlled by a respective program stored in the control unit of the thread dispensing device. In a preferred embodiment, the shifting means include a manually operable lever. This allows a compact design of the thread dispensing device with a reduced control effort.

Furthermore, there is provided a clipping machine for producing sausage-shaped products, like sausages, with a tubular or bag-shaped packaging casing containing a flowable filling material and a suspension element attached to the tubular or bag-shaped casing, wherein the suspension element consists of thread. The clipping machine comprises a filling tube on which the tubular or bag-shaped packaging casing is stored and through which filling material is fed in a feeding direction into the tubular or bag-shaped packaging casing, gathering means for gathering the filled tubular or bag-shaped packaging casing and for forming a plait-like portion thereto and a clipping device for applying at least one closure means, like a closure clip, to the plait-like portion for closing the just filled portion of the tubular or bag-shaped packaging casing. The clipping machine further comprises a device for dispensing thread according to the present invention. In a preferred embodiment, the thread dispensing device is arranged in an area above the clipping device. Of course, the thread dispensing device can be arranged below the clipping device or in a neighborhood to the clipping device.

Further according to the present invention, there is provided a method for dispensing thread by a thread dispensing device in a clipping machine for producing sausage-shaped products, including the steps of:.

The present invention also provides a method for producing sausage-shaped products, like sausages, with a tubular or bag-shaped packaging casing containing a flowable filling material and a suspension element attached to the tubular or bag-shaped casing, wherein the suspension element consists of thread, including the steps of:.

The method further comprises the step of guiding thread through a guide unit of the dispensing device.

The method may also comprise the step of selecting a predefined operation mode for operating the thread dispensing device.

The clipping machine equipped with the thread dispensing device according to the present invention, the method for producing sausage-shaped products as well as the method for dispensing thread provide all advantages as explained in conjunction with the inventive thread dispensing device alone.

Further advantages and preferred embodiments of the present invention will be described in the following together with the drawings listed below. The expressions "left", "right", "below" and "above" used in the following description, are referred to the drawings in an alignment such that the reference numbers and the notation of the figures used can be read in normal orientation.

A clipping machine CM for producing sausage-shaped products S shown schematically in <FIG>, comprises, as main components, a filling tube <NUM> having a longitudinally and horizontally extending center axis A, with a discharge opening for discharging a filling material at its left end <NUM> and a feeding opening for feeding in a feeding direction F the filling material to the discharge opening of filling tube <NUM>, for example by a feeding pump (not shown), at its right end <NUM>, and a casing brake assembly <NUM> arranged coaxially with filling tube <NUM> in the region of the left end <NUM> of filling tube <NUM>. Filling tube <NUM> is made of a suitable material, like stainless steel. A supply of tubular packaging casing M made of a thin sheet material is stored on filling tube <NUM>. From the supply of tubular packaging casing M, tubular packaging casing M is pulled-off during the process of manufacturing the sausage-shaped products S, in particular by the feeding pressure for filling the filling material into tubular packaging casing M.

Clipping machine CM further comprises a clipping device <NUM> for closing a filled tubular packaging casing M by applying closure means, like closure clips C, to a plait-like portion P, and gathering means <NUM> for gathering the filled tubular packaging casing M and for forming said plait-like portion P thereto. These components are all arranged downstream filling tube <NUM>.

As can be inferred from <FIG>, clipping device <NUM> is positioned immediately downstream left end <NUM> of filling tube <NUM>, and coaxially aligned to filling tube <NUM>. Clipping device <NUM> comprises a first and a second clipping tool <NUM>, <NUM> formed by a punch <NUM> and a die <NUM>. It has to be noted that punch <NUM> and die <NUM> may apply and close a single closure clip C for closing the just filled tubular packaging casing M, or may apply and close two closure clips C at the same time, a first closure clip C for closing the rear end of the just filled tubular packaging casing M for forming a sausage-shaped product S, and a second closure clip C for closing the front end of a tubular packaging casing M subsequently to be filled. Gathering means <NUM> include a first displacer unit <NUM> and a second displacer unit <NUM>, wherein first displacer unit <NUM> is positioned downstream second displacer unit <NUM>. First and second clipping tools <NUM>, <NUM> of clipping device <NUM> may be positioned between first and second displacer units <NUM>, <NUM>, at least for applying and closing one or two closure clips C to plait-like portion P.

For discharging a sausage-shaped product S just produced from clipping machine CM, downstream clipping device <NUM>, a discharge device may be arranged, which may comprise a conveyor belt and guide rollers. In a simple case, the discharge device may be a chute.

In the clipping machine CM according to <FIG>, ring-shaped sausage products may be produced. For forming tubular packaging casing M into a ring shape while being filled, a thread T is dispensed to clipping machine CM by a device for dispensing a thread or a thread dispensing device DD in a dispensing direction D.

Thread dispensing device DD can be arranged below filling tube <NUM> or clipping device <NUM>. In another arrangement of thread dispensing device DD, it can be provided above filling tube <NUM> or clipping device <NUM>. The latter allows a more easy operation of the device DD by an operator.

Thread T is attached to the front end of the tubular packaging casing M to be filled by a closure clip C that closes the front end of tubular packaging casing M. Thread T dispensed or fed by thread dispensing device DD to clipping machine CM is received from a supply of thread T or thread supply TS, like a spool, transported through thread dispensing device DD and guided or fed into the closing region of clipping machine CM, in which gathering means <NUM> and clipping device <NUM> are arranged for gathering and closing the filled tubular packaging casing M. The supply of thread may be also arranged above or below filling tube <NUM> and/or clipping device <NUM>.

The feeding of the thread can be started before the filling process begins. In such a case, the thread can form a loop which is suspended during the filling of the sausage-shaped product. Alternatively, the feeding of the thread can be started simultaneously with the beginning of the filling process.

During the filling tubular packaging casing M, a length of thread T is dispensed by thread dispensing device DD, that is shorter than the length of tubular packaging casing M which forms a complete sausage-shaped product S. Accordingly, after a length of tubular packaging casing material M which matches the length of the suspended thread T, is filled, the tubular packaging casing M while further being filled, forms a ring, as can be seen in <FIG>.

After the desired length of tubular packaging casing M is filled, gathering means <NUM> gather the filled tubular packaging casing M, and form a plait-like portion P thereto.

In specific cases, in which first displacer unit <NUM> is moved relative to second displacer unit <NUM> in feeding direction F along center axis A of filling tube <NUM>, for forming an elongated plait-like portion P, a second length of thread T which corresponds to the length of the elongated plait-like portion, may be dispensed by thread dispensing device DD.

In the case that the dispensed length of thread T that extends between the front end of sausage-shaped product S and its rear end, is longer than a desired length, thread dispensing device DD may retract thread T about a defined length such that the remaining length of thread T between the front end and the rear end of sausage-shaped product S matches a predetermined length of thread T.

After thread T extending between the front end and the rear end of sausage-shaped product S has the predetermined length, clipping device <NUM> places and closes at least one closure clip C at plait-like portion P, for closing the rear end of just filled tubular packaging casing M forming a ring. By said closure clip C, thread T is fixed to the rear end of the just filled tubular packaging casing M.

Clipping device <NUM> may simultaneously place and close a second closure Clip C at plait-like portion P for closing the front end of the next tubular packaging casing M subsequently to be filled, and for fixing thread T thereto.

Thread T and plait-like portion P are cut upstream closure clip C that closes filled tubular packaging casing M for separating sausage-shaped product S just produced from the remaining supply of tubular packaging casing M and thread T. Sausage-shaped product S may than be removed from clipping machine CM by a respective discharge device.

<FIG> and <FIG> show an embodiment of a dispensing device for dispensing thread, or thread dispensing device DD.

Thread dispensing device DD comprises a transport unit <NUM> for transporting thread T, a drive unit <NUM> for driving transport unit <NUM>, a gear unit <NUM> for transmitting torque from drive unit <NUM> to transport unit <NUM>, guide means <NUM> for guiding thread T through thread dispensing device DD and a shifting unit <NUM> for reversibly interrupting the transport of thread T. Thread dispensing device T according to <FIG> and <FIG> further comprises a switch unit <NUM> for manipulating drive unit <NUM>. The components of thread dispensing device DD are supported by a frame work <NUM> by which thread dispensing device DD may be mounted to a clipping machine CM. Clipping machine CM can be a new or an already existing machine. In other words, thread dispensing device DD can also be a retrofitting kit for existing machines.

Drive unit <NUM> includes an electric motor <NUM>, like a stepper motor, connected to a control unit and a respective power source by a connector unit <NUM> (cf. Motor <NUM> and connector unit <NUM> are covered by a motor coverage <NUM> as shown in <FIG>. Motor <NUM> has a drive shaft <NUM> that extends into gear unit <NUM>.

Gear unit <NUM> comprises a gear coverage <NUM> and a carrier plate <NUM> for rotatably supporting the movable elements of gear unit <NUM>, like rotation shafts with respective toothed wheels thereon, as it can particularly seen in <FIG> where gear box coverage <NUM> has been omitted, and as it is explained in detail in conjunction with <FIG> below.

Transport unit <NUM> includes a first cylindrical drive roller <NUM> and a second cylindrical drive roller <NUM>, the rotation axes of which are arranged parallel to each other in a substantially horizontal plane. Rollers <NUM>, <NUM> are arranged on rotatably supported shafts <NUM>, <NUM>.

Rollers <NUM>, <NUM>, according to <FIG>, <FIG> and <FIG>, are in a transport position, in which they abut each other along a horizontal contact line. A thread T when positioned between rollers <NUM>, <NUM>, is forwarded when rollers <NUM>, <NUM> are driven by drive unit <NUM>.

Shifting unit <NUM> comprises a shifting element or lever <NUM> having a plate-shaped actuation portion <NUM> that extends substantially horizontal and along the left side of carrier plate <NUM> towards the front side of thread dispensing device DD as shown in <FIG>. At the rear end of actuation portion <NUM> of shifting element or lever <NUM>, two lugs <NUM> extend downwardly from actuation portion <NUM>, parallel to each other and to carrier plate <NUM>, and with a gap between lugs <NUM> that corresponds to the axial length of drive rollers <NUM>, <NUM> of transport unit <NUM> (cf.

Shifting unit <NUM> further comprises a pivot shaft <NUM> that extends horizontally through carrier plate <NUM> in which shaft <NUM> is rotatably supported. Lever <NUM> is mounted to the portion of shaft <NUM> that extends over carrier plate <NUM>, to be reversibly pivoted about the longitudinal axis of shaft <NUM>. In the region of the lower ends of lugs <NUM>, horizontally arranged and coaxially aligned holes are provided through which shaft <NUM> of transport unit <NUM> extends into gear unit <NUM>. In carrier plate <NUM>, a guide means or guide slot <NUM> is arranged, which has the shape of a circular segment with a center point coinciding with the longitudinal axis of shaft <NUM>. This enables shaft <NUM> to be pivoted about shaft <NUM> and in parallel orientation thereto, upon reversible actuation of lever <NUM>. In other words, shaft <NUM> is moved on an at least substantially circular-shaped trajectory around shaft <NUM>.

Transport unit <NUM> further includes a support plate <NUM> arranged parallel to carrier plate <NUM> of gear unit <NUM>, on its left side in <FIG> and with a gap therebetween that corresponds to the width of lever <NUM>. Support plate <NUM> rotatably supports the left end of shaft <NUM> of transport unit <NUM> and the left end of shaft <NUM> of shifting unit <NUM>. In <FIG>, support plate <NUM> has been omitted such that the left ends of shafts <NUM> and <NUM> are visible.

Guide means <NUM> for guiding thread T through thread dispensing device DD include an upper guide element <NUM> coupled to the upper side of gear box coverage <NUM>, in a recess having a shape that corresponds to the shape of guide element <NUM>, and extends leftwards in <FIG>. At its left end, plate-like guide element <NUM> has a vertical through-hole <NUM> aligned approximately vertically above the contact line of rollers <NUM>, <NUM> of transport unit <NUM>. Below rollers <NUM>, <NUM>, viewed in a vertical direction, a lower guide element <NUM> of guide means <NUM> is arranged with a through-hole <NUM> aligned preferably and at least approximately with through-hole <NUM> of guide element <NUM> and the contact line between rollers <NUM>, <NUM>. Guide element <NUM> is mounted to carrier plate <NUM> by a vertically arranged plate-like holder <NUM>.

Additionally, in actuation portion <NUM> of lever <NUM> of shifting unit <NUM>, a guide hole <NUM> is provided and preferably aligned with through-hole <NUM> of guide element <NUM>, the contact line between rollers <NUM>, <NUM> and through-hole <NUM> of guide element <NUM>.

Guide element <NUM> with hole <NUM>, guide hole <NUM> in lever <NUM> and guide element <NUM> with hole <NUM> form guide means <NUM> for guiding thread T through thread dispensing device DD, as can be seen in <FIG> which is a schematic sectional view through guide means <NUM> of thread dispensing device DD along the guide path of thread T.

As particularly can be seen in <FIG>, a return member <NUM> is arranged between the front end of actuation portion <NUM> of lever <NUM> and the front end of guide element <NUM>. Return member <NUM>, in the embodiment of <FIG> and <FIG>, is a pneumatic spring including a piston/cylinder arrangement with pressurized gas in the cylinder. In <FIG> and <FIG>, lever <NUM>, and thus, rollers <NUM>, <NUM> are in a transport position with rollers <NUM>, <NUM> are in contact with each other such that thread T arranged between rollers <NUM>, <NUM> (cf. <FIG>), is forwarded when drive <NUM> is actuated.

For interrupting the transport or feeding of thread T, lever <NUM> may be pushed downwardly on its end at which pneumatic spring <NUM> is attached (cf. <FIG>), for example by an operator, whereby first roller <NUM> is shifted about the pivot axis or shaft <NUM> of lever <NUM> along guide slot <NUM> and away from second roller <NUM> into a release position.

Return member or pneumatic spring <NUM> acts on lever <NUM> such that, when lever <NUM> is released by the operator, lever <NUM> and first roller <NUM> are automatically be shifted back into the transport position as shown in <FIG> and <FIG>.

Additionally, a cutting device or cutter unit <NUM> is provided at plate-like holder <NUM> which can in particular be seen in <FIG>. Cutter unit <NUM> is arranged below or downstream of transport unit <NUM>, referred to the feeding or dispensing direction of thread T which is oriented from upper guide element <NUM> to lower guide element <NUM>, and includes a blade holder <NUM> which is fixed to plate-like holder <NUM>. Blade holder <NUM> has a vertically extending slot <NUM>. A blade <NUM> is clamped between blade holder <NUM> and plate-like holder <NUM> such that a sharpened edge of blade <NUM> extends into slot <NUM>. Cutter unit <NUM> may be used for example by an operator for cutting thread T, e.g. when exchanging thread T by another kind of thread T, for cleaning the free end of thread T before inserting it into thread dispensing device DD, or for removing defective portions of thread T.

<FIG> is a sectional view through gear unit <NUM> of thread dispensing device DD viewed from stepper motor <NUM>.

Besides the elements already explained in conjunction with <FIG> and <FIG>, like gear coverage <NUM> and carrier plate <NUM>, gear unit <NUM> further comprises a pinion <NUM>, a first intermediate gearwheel <NUM>, a second intermediate gearwheel <NUM>, a first drive gearwheel <NUM> and a second drive gearwheel <NUM>.

Pinion <NUM> is arranged at that portion of shaft <NUM> of motor <NUM> which extends into gear unit <NUM>, and engages first intermediate gearwheel <NUM> that is arranged on a shaft <NUM> which is rotatably supported by carrier plate <NUM>. First intermediate gearwheel <NUM> engages second intermediate gearwheel <NUM> rotatably arranged at pivot shaft <NUM> of shifting means <NUM>, and first drive gearwheel <NUM> on shaft <NUM> of transport unit <NUM>. Second intermediate gearwheel <NUM> engages second drive gearwheel <NUM> mounted on shaft <NUM> of transport unit <NUM>.

As can be seen in <FIG>, pinion <NUM> when clockwise driven by motor <NUM>, drives first intermediate gearwheel <NUM> counterclockwise. First intermediate gearwheel <NUM> in turn rotates second intermediate gearwheel <NUM> and first drive gearwheel <NUM> in clockwise direction. Accordingly, second drive gearwheel <NUM> is rotated counterclockwise by second intermediate gearwheel <NUM>.

First roller <NUM> of transport unit <NUM> is mounted on shaft <NUM> driven by second drive gearwheel <NUM>, and second roller <NUM> is mounted on shaft <NUM> driven by first drive gearwheel <NUM>. Thus, while pinion <NUM> is driven clockwise, thread T arranged between rollers <NUM>, <NUM> is transported downwardly through thread dispensing device DD. Accordingly, when pinion <NUM> is driven counterclockwise, thread T is fed upwardly through thread dispensing device DD.

For producing sausage-shaped products S, particularly ring-shaped sausage-shaped products, in clipping machine CM, tubular packaging casing M is stored on filling tube <NUM>. The front end of tubular packaging casing M is closed by a closure clip C, and the front end of thread T is fixed to the front end of tubular casing M by said closure clip C.

Moreover, the front end of a thread T is pulled by an operator from thread supply TS and is threaded in upper guide element <NUM>. Thread T is then pulled further by the operator to transport elements <NUM>, <NUM> and is guided therebetween wherein transport element <NUM> is shifted away from transport element <NUM> via pushing lever <NUM> downwardly by the operator. When thread T is positioned between transport elements <NUM>, <NUM>, the operator releases lever <NUM> so that transport element <NUM> comes in contact once again with transport element <NUM>. Finally, thread T is threaded through lower guide element <NUM> and is fed to the closing region of clipping machine CM.

Together with the filling process or at a predetermined time point before or after the filling process has been started, a predefined length of thread is dispensed by thread dispensing device DD. Thereafter, the transport of thread T is stopped and thread T is clamped in thread dispensing device DD, e.g. by first and second rollers <NUM>, <NUM>, for preventing thread from being further pulled-off from thread supply TS.

The filling process is continued until a desired portion of filling material has been fed through filling tube <NUM> into tubular packaging casing M, or the filled tubular packaging casing M has a desired length. During filling, the filled tubular packaging casing reaches a length that corresponds to the length of thread T dispensed by thread dispensing device DD, and the front end of the filled tubular casing M is held in its position relative to filling tube <NUM>. During the further filling process, and dependent on the suspended length of thread T, filled tubular packaging M forms a ring or at least a segment of a ring.

After a predetermined portion of filling material has been fed into tubular packaging casing M, feeding of filling material is stopped and the filled tubular packaging casing is gathered by gathering means <NUM>, for forming a plait-like portion P thereto.

Dependent on the length of thread between the front end of filled tubular casing M and its rear end, clipping device <NUM> places and closes two closure clips C to plait-like portion P, a first closure clip C for closing the rear end of filled tubular casing M, and a second closure clip C for closing the front end of the tubular casing material M subsequently to be filled. Thereafter, plait-like portion P and thread T are cut by a respective cutting device between the two closure clips C for separating sausage-shaped product S from the remaining tubular packaging casing M and from the supply of thread T.

It has to be noted that it is also possible to place and close only one closure clip C to plait-like portion P, for closing the rear end of filled tubular packaging casing M, and in a further clipping step, to place a further closure clip C the close the front end of tubular packaging casing M subsequently to be filled.

In both cases, thread T is fixed to the respective end of tubular packaging casing M by said closure clip C.

In the case that the length of thread T between the front end of filled tubular casing M and its rear end exceeds a desired length, e.g. process-related, thread T may be pulled back by thread dispensing device DD about a respective length, after filled tubular casing M has been gathered by gathering means <NUM>, but before a closure clip C has been placed and closed at plait-like portion P by clipping device <NUM>.

In some cases, it is desired to form an elongated plait-like portion P to the filled tubular packaging casing M, e.g. for producing slack filled sausages. For producing slack filled sausage, displacer unit <NUM> of gathering means <NUM> positioned downstream displacer unit <NUM>, is moved in feeding direction F away from displacer unit <NUM> in a spreading operation, thereby, an elongated plait-like portion P is formed to filled tubular packaging M.

During the spreading operation or at a suitable time point before or after the spreading operation has been started, an additional length of thread T may be dispensed by thread dispensing device DD. This additional length corresponds to the length of the spreading path about which displacer unit <NUM> is moved away from displacer unit <NUM>. Particularly when processing sensitive packaging casing, the casing material is preserved, since possible friction between thread T and tubular packaging casing M during the spreading operation is prevented.

Thread dispensing device DD includes a motor <NUM> which may be a stepper motor, and a control unit for controlling motor <NUM>. The control unit may be provided with a large number of programs for controlling motor <NUM>, e.g. the dispensing speed, the dispensed length, or the number of lengths dispensed during one production cycle. Accordingly, thread dispensing device DD may be adapted to a great variety of products to be produced on clipping machine M.

The control unit of thread dispensing device DD may be incorporated in thread dispensing device DD, such that it may work independently from clipping machine CM, or only needs to be provided with a signal corresponding to the start of a production cycle, or the production process at all. Thread dispensing device DD, after the receipt of a respective start signal, may than operate independent from clipping machine CM and on the basis of a selected program stored in the control unit of thread dispensing device DD.

Alternatively, the control unit of thread dispensing device DD may also be incorporated in clipping machine CM. In this case, while selecting a product to be produced by clipping machine CM, a program for controlling thread dispensing device DD may automatically be selected by clipping machine CM. Otherwise, also the operator may manually select a program for controlling thread dispensing device DD at the control unit of clipping machine CM.

In a simple version of thread dispensing device DD, selecting switch <NUM> is provided at thread dispensing device DD for selecting only the length of thread T to be dispensed, and an operator starts and stops thread dispensing device DD for each production cycle. Naturally, thread dispensing device DD may also designed to receive a start or stop signal from the control unit of clipping machine CM, and the operator selects the length of thread T to be dispensed by switch <NUM>.

In another embodiment of thread dispensing device DD, switch <NUM> may be used for setting other parameters, like the length of breaks between two subsequent dispensing operations.

Switch <NUM> may also be used for setting thread dispensing device DD into or out of operation.

Depending on the program presently running for controlling clipping machine CM or thread dispensing device DD, parameters of thread dispensing device DD may also varied during the production process by switch <NUM>, e.g. in adaption to varying properties of tubular packaging casing M or thread T.

As explained in conjunction with <FIG>, the first and second roller <NUM>, <NUM> of transport unit <NUM> are both driven by drive unit <NUM>. Thereby, slip is prevented between thread T and one of rollers <NUM>, <NUM>, and wear is prevented and thread T is surely transported straight through transport unit <NUM>.

Additionally, the specific construction of shifting unit <NUM> enables the removal of first roller <NUM> from second roller <NUM>, without interrupting the drive of first roller <NUM>, since second drive gearwheel <NUM> stays in engagement with second intermediate gearwheel <NUM> while first roller <NUM> is moved away from second roller <NUM>. When pushing the front end of actuation portion <NUM> of lever <NUM> downwards, lever <NUM> rotates about shaft <NUM>. Shaft <NUM> with first roller thereon, is moved along a circular path about shaft <NUM> and within guide slot <NUM> in carrier plate <NUM>. Accordingly, second drive gearwheel <NUM> at shaft <NUM> also rotates about shaft <NUM> which also carries second intermediate gearwheel <NUM> which is engaged with second drive gear wheel <NUM>. Thus, during the pivot movement of lever <NUM>, second intermediate gearwheel <NUM> and second drive gearwheel <NUM> remain in engagement with each other, and first roller <NUM> at shaft <NUM> is driven also during the pivot movement of lever <NUM>. Thereby, the transport of thread T as well as the interruption of the transport of thread T may securely be controlled, and slip and wear between thread T and rollers <NUM>, <NUM> is prevented. When releasing lever <NUM>, return member <NUM> automatically pushes lever <NUM> into the transport position shown in <FIG>.

Thread T in the sense of the present invention may be any longitudinally extending material, like strings, filaments or ribbons. The design of thread dispensing device DD allows the transport of thread of various materials and cross-section. Thus, it is possible to transport flat material, which may be attached to a tubular packaging of a respective product, like a tubular net for producing netted fruits or any other netted items. The ribbon attached to such a net product may form a handle. Alternatively or additionally, a ribbon may also be used a label with information regarding the packaged product printed thereon.

The specific embodiment according to <FIG> has been explained in conjunction with a clipping machine for producing sausage-shaped products S. Accordingly, thread dispensing device DD is mounted to a clipping machine CM such that thread T may be dispensed into the closing region of clipping machine CM, where gathering means <NUM> and clipping device <NUM> are arranged. Thread dispensing device DD may be arranged above or below the closing region of clipping machine CM, as long as an operator may securely operate thread dispensing device DD and thread T is reliably dispensed to clipping machine CM.

Additionally, in order to ensure a correct feeding of thread to clipping machine CM, respective guide elements, like guide rollers, may be provided for guiding thread T dispensed by thread dispensing device DD into the closing region of clipping machine CM for accurately being grasped by gathering means <NUM>.

Return member <NUM> has been described as being a pneumatic spring including a piston/cylinder arrangement with pressurized gas in the cylinder, for automatically pushing lever <NUM>, and thus, transport unit <NUM> into its operation position, after being manually actuated. However, it is also possible to design the return member such that it may automatically be actuated, e.g. including a separate drive, like an electric or pneumatic drive, and being controlled by a program for controlling thread dispensing device DD. The respective control program may include steps for interrupting the transport of thread T, or to start the transport of thread T. Accordingly, it is also possible to establish an emergency routine which automatically interrupts the transport of thread T in emergency case.

Claim 1:
A device for dispensing thread (DD) in a clipping machine for producing sausage-shaped products, comprising a transport unit (<NUM>) having at least a first and a second transport element (<NUM>, <NUM>) for a defined transport of a thread (T);
a drive unit (<NUM>) for driving the first and second transport element (<NUM>, <NUM>); and
a shifting unit (<NUM>) for reversibly shifting the first transport element (<NUM>) relative to the second transport element (<NUM>).