Patent Description:
The invention relates to a strap end connecting device having a separating device according to claim <NUM>.

The strap end connecting device of the generic type is what is known as an end sealer (also called a strap end connector), as is used in certain types of strapping systems. Here, the strap end connector is provided in a strapping system as a fastening head, by way of which two straps are severed one after another directly in one working step, and subsequently in each case one end of the first and of the second strap can be connected to one another in a further working step of the fastening head. Two fastenings which belong to two different strappings are typically formed at the same time and in parallel on both sides of the fastening head. In the case of packaged goods which are conveyed through a portal of a strapping system, connections of this type serve at the same time for strapping of a front first packaged good and for strapping of a following second packaged good which is situated behind it. In the case of the front packaged good, it is a strap fastening which is situated on the rear side of the first packaged good in the conveying direction. In the case of the following second packaged good, it is a strap fastening which is situated on the front side of the second packaged good, once again as viewed in the conveying direction. After its front fastening is produced, the second packaged good is usually transported into the strap with said second fastening. The conveying movement of the packaged good then brings it about that the strap bears against the front side of the second packaged good and against the two sides of the packaged good. Two assemblies of the strap end connecting device, of which in each case one is arranged at this time on in each case one side of the respective packaged good, are then moved toward one another behind the packaged good. Here, each of said two assemblies of the strap end connector guides one side of the strapping to be formed and moves it behind the packaged good. Here, one of said two assemblies comprises a separating device for severing the two strapping sides from their strap supply. Moreover, one of the two assemblies comprises a pressing unit, by way of which the two strap ends are brought into contact against one another. One of the two assemblies comprises a heating device, by means of which heat is introduced locally into the two strap ends which lie above one another, as a result of which the two strap ends are heated to such an extent that the plastic of the two strap ends melts locally, flows into one another, is welded to one another and, as a result, the associated strap ends are connected to one another after cooling.

A strapping system of this type is previously known from <CIT>, in the case of which the heating device is configured as a hot welding device. In the case of said device, heating elements are heated by way of electric current, which heating elements are in each case brought into contact against one of the two strap ends which lie above one another. Moreover, the strapping system which is disclosed therein and has been offered for a long time by the company Endra B. , NL-<NUM> AL Oss has a strap end connector, the hot welding device of which is provided with a heating bead which projects in the direction of the other assembly. Together with the heating elements, the heating bead is heated electrically and serves to sever the two straps. This solution has the disadvantage, however, that comprehensive insulation measures have to be taken, in order that the entire strapping system does not carry current during the contact of the heating bead with the second assembly. Moreover, the heating bead becomes clogged over time with melted plastic deposits which have to be removed regularly, in order that the functional reliability is not impaired.

Moreover, a strap end connector is previously known from <CIT>, in the case of which strap end connector the heating device is configured as a vibration welding device which is assigned to one of the two assemblies. In the case of said vibration welding device, the heat which is required for melting of the plastic is introduced into the strap ends by means of welding elements which are pressed against the two strap ends and are moved to and fro in an alternating and vibrating manner. The other assembly is provided with a mechanical edge or blade which is moved into the two straps in order to sever the latter. In this solution, therefore, the plastic straps are severed by way of a mechanical cutting operation. This solution has the disadvantage that it is not fully functionally reliable and, above all, relatively thick straps can cause difficulties in terms of being severed reliably. In addition, cutting of the strap and welding of the strap ends cannot take place in the same cycle without an additional lift. A strap end connecting device according to preamble of claim <NUM> is known from <CIT>.

The invention is therefore based on the object of providing an improvement in the case of strap end connectors, by way of which improvement functionally reliable severing becomes possible even in the case of different strap thicknesses with maintenance of the severing means which is as low as possible.

Said object is achieved according to the invention by way of end connecting device as claimed in claim <NUM> and by way of a strapping system as claimed in claim <NUM>.

By virtue of the fact that the at least one strap is cut and is not severed by way of heating, no deposits are produced on the heating element and odor production is therefore also at least reduced. A strap end connecting device (called a strap end connector for short) having a separating device according to the invention can be operated without cleaning intervals or with relatively long cleaning intervals. The risk of contamination of the cutting edge is reduced. Functionally reliable severing is possible even in the case of different strap thicknesses with maintenance of the blade which is nevertheless as low as possible. Wear of the heating element is reduced, since a highly loaded separating edge can preferably be dispensed with on the heating element itself. The edge of the blade can be resharpened, in particular by stropping, with the result that long service lives of the blade can be achieved. The sharpening of the blade can take place in a state, in which it is dismantled from the heating element. Cutting of the strap and welding of the strap ends can take place in the same cycle without an additional lift.

The separating device has a carrier, on which the blade is arranged, the carrier being provided for attaching or arranging on that assembly of the strap end connecting device which has the heating element. The blade is arranged in the vicinity of the heating element by means of the carrier; vicinity can be understood to mean a spacing, in the case of which, by means of the heating element, the blade experiences or can experience a temperature increase on account of the heating element despite a spacing between the heating element and the blade. A spacing between the heating element and the blade is preferably adjustable, for example by way of suitable structural measures. As a result, a temperature of the blade can be influenced in a targeted manner. The carrier can have positioning aids for arranging on the assembly which has the heating element. The carrier can be capable of being screwed to the assembly which has the heating element, in particular in a releasable manner. There should preferably not be direct physical contact between the blade and the heating element.

According to the invention, the blade is e arranged in an electrically insulated manner on the assembly which has the heating element. This avoids a situation where an electric current can flow from the heating element to the blade and can electrify further components of the strap end connecting device.

The edge of the blade and a movement direction of the blade preferably enclose an angle of less than <NUM>°, preferably an angle of <NUM>°. This angle makes an optimized cutting process possible. The straps preferably run perpendicularly with respect to the movement direction of the blade. The blade then advantageously has an edge with preferably a linearly running cutting edge which is arranged at an angle of preferably at least <NUM>°, at most preferably <NUM>°, with respect to the straps to be severed. In order to ensure high stability of the blade and a satisfactory cutting process, an edge angle of the blade should have a value between <NUM> and <NUM>°, and should preferably have a value of <NUM>°.

The object is achieved by way of a strap end connecting device for a strapping system as claimed in claim <NUM>.

The strap end connecting device preferably has a first assembly for heating, in particular welding, at least two strap ends to be connected to one another of a strap, and a second assembly for placing, in particular pressing, the strap ends which are to be connected to one another onto one another and/or onto the first assembly. The first assembly for heating, in particular welding, at least two strap ends to be connected to one another of a strap can be an assembly which has the heating element. Welding can take place, for example, by means of a hot welding process or a rotary friction or vibration welding process.

The first assembly can have a heatable first fastening head which is coupled to or preferably provided with a heating element. The heating element (for example, an electric heating element) can be integrated into the first fastening head. The second assembly can have a second fastening head which is decoupled from the heating element or is preferably not provided with a heating element. During operation of the strap end connecting device, the temperature of the first fastening head is preferably higher than the temperature of the second fastening head on account of the heating element. The heating element is a constituent part of a welding unit of the first assembly. The heating element can also, however, be a heating element which is configured separately from the welding unit for heating the blade by way of heat radiation. In one preferred solution, in which the heating element is a constituent part of the welding unit of the first assembly, the temperature increase of the blade in comparison with the ambient temperature in the region of the strapping apparatus can also take place by way of heat radiation of the heating element.

The blade can preferably be fed in together with the welding unit in the direction of a pressing unit of the second assembly. The blade can be heated particularly effectively by way of heat radiation and is nevertheless itself not electrified by the heating element which is electrically heatable and the blade is arranged at a spacing from the heating element. The blade can be heated to a higher operating temperature in comparison with an ambient temperature by the heating element, in particular electrically generated heat radiation.

The blade is insulated electrically from an electrically heated heating element by way of an insulation means. The blade is preferably arranged on a carrier which is connected to the insulation means. A spacing is provided between the blade and the heating element. Here, the spacing of the blade from the heating element is preferably <NUM>, as a result of which a sufficient electric insulation of the blade is ensured. The invention is not restricted to said dimension, however. A multiplicity of other spacing dimensions between the blade and the heating element can also be provided in conjunction with said preferred embodiment or other preferred embodiments of the invention.

In addition, the object is achieved by way of a strapping system as claimed in claim <NUM>.

Further preferred refinements of the invention result from the claims, the description and the drawing.

The invention will be described in greater detail using exemplary embodiments which are shown purely diagrammatically in the figures, in which:.

<FIG> and <FIG> show a strapping system <NUM> which has a gantry <NUM> and a supply device <NUM> for storing and for providing two straps <NUM>, <NUM> made from plastic for producing self-contained ring-like strapping straps for packaged goods. The gantry <NUM> comprises a strap end connecting device <NUM> with a first fastening head <NUM> and a second fastening head <NUM>. The fastening heads <NUM>, <NUM> serve for an advancing movement of the two straps <NUM>, <NUM> toward one another, for severing the two straps <NUM>, <NUM>, and for welding a first strap end 4a of the first strap <NUM> to a first strap end 5a of the second strap <NUM>, and for welding a second strap end 4b of the first strap <NUM> to a second strap end 5b of the second strap <NUM>.

Two strap fastenings which belong to two different strappings are formed at the same time and in parallel by way of said welding of the strap ends 4a, 4b, 5a, 5b. In the case of packaged goods which are conveyed through the gantry <NUM> of the strapping system <NUM>, a strapping of a front packaged good and a strapping of a subsequent, rear packaged good are produced at the same time. In the case of the front packaged good, it is a strap fastening which is situated on the rear side of the first packaged good in a conveying direction <NUM>. In the case of the following second packaged good, it is a strap fastening which is situated on the front side of the second packaged good, once again as viewed in the conveying direction <NUM>. After its front fastening is produced, the rear packaged good is usually transported into the strap with said second fastening. The conveying movement of the packaged good in the conveying direction <NUM> then brings it about that the strap bears against the front side of the second packaged good and against the two sides of the packaged good. In the above-described way, therefore, any desired number of packaged goods can be conveyed through the gantry <NUM> and can be provided with a strapping.

<FIG> show the strap end connecting device <NUM>. The strap end connecting device <NUM> has the first fastening head <NUM> and the second fastening head <NUM>.

The first fastening head <NUM> has a housing <NUM>, a pneumatic cylinder <NUM>, and a welding unit <NUM>. A strap clamp <NUM> is fastened pivotably to the first fastening head <NUM> in such a way that the straps <NUM>, <NUM> can be fixed in the strap end connecting device <NUM> by means of the strap clamp <NUM>. The welding unit <NUM> comprises an electrically heatable heating element <NUM> as a first assembly for heating, in particular welding, the straps <NUM>, <NUM> in the region of the strap ends 4a, 4b, 5a, 5b. The heating element <NUM> is configured as an electrically heatable heating plate. The heating element <NUM> is fastened on an insulation block <NUM> made from an electrically non-conductive material. By means of the pneumatic cylinder <NUM>, the insulation block <NUM> with the heating element <NUM> which is fastened thereon can be moved to and fro transversely with respect to the conveying direction <NUM> and in the direction of the second fastening head <NUM> in and counter to a movement direction <NUM> of the fastening heads <NUM>, <NUM>. The blade <NUM> moves together with the heating element <NUM> relative to the housing <NUM> and parallel to the movement direction <NUM>.

The first fastening head <NUM> has a separating device <NUM>. The separating device <NUM> has a carrier <NUM> and a blade <NUM>. The blade <NUM> is fastened to the carrier <NUM>, in the present case is screwed by means of a bolt <NUM>. On a side of the insulation block <NUM> which faces away from the blade <NUM>, the carrier <NUM> is fastened to a further electrically insulated component <NUM> of the fastening head <NUM>, in the present case is screwed by means of two bolts <NUM>. In addition, the carrier <NUM> bears against the insulation block <NUM>. On account of the fastening of the carrier <NUM> to the insulated component <NUM>, the carrier is insulated electrically from the current-conducting heating element, with the result that the blade <NUM> cannot come into contact with the electric current via the carrier <NUM>. The blade <NUM> is arranged at a spacing from the heating element <NUM>. As a result, the blade <NUM> is additionally insulated by means of an air gap from the current-conducting heating element <NUM>. The smallest spacing between the blade <NUM> and the heating element <NUM> is preferably <NUM> or more.

The second fastening head <NUM> has a housing <NUM>, a pneumatic cylinder <NUM>, and a pressing unit <NUM>. By means of the pneumatic cylinder <NUM>, the pressing unit <NUM> can be moved forward and backward transversely with respect to the conveying direction <NUM> and in the direction of the first fastening head <NUM> in and counter to the movement direction <NUM> of the fastening heads <NUM>, <NUM>. The pressing unit <NUM> has a pusher <NUM> for pressing the strap ends 4a, 4b, 5a, 5b which are heated by the heating element <NUM>. As a result, the strap ends 4a, 4b, 5a, 5b can be welded to one another. The pusher <NUM> is shaped in a U-shaped manner in such a way that the blade <NUM> can cut the second strap <NUM> which bears against the pusher <NUM>, without the blade <NUM> colliding with the pusher <NUM>.

<FIG> show one preferred embodiment of the blade <NUM>. The blade <NUM> has an edge <NUM> with a preferably linearly running cutting edge which is arranged at an angle <NUM> of preferably at least <NUM>°, very preferably <NUM>°, with respect to the straps <NUM>, <NUM> which are to be severed. An angle between the movement direction <NUM> of the fastening heads <NUM>, <NUM> and the edge <NUM> is preferably at most <NUM>°, very preferably <NUM>°. A supporting face <NUM> of the blade <NUM> runs parallel to the movement direction <NUM> of the fastening heads <NUM>, <NUM>. A blind bore which is provided with an internal thread runs in the blade <NUM> perpendicularly with respect to the supporting face <NUM>. The bolt <NUM> for fastening the blade <NUM> to the carrier <NUM> can be screwed into said internal thread.

An edge angle <NUM> of the blade <NUM> is preferably <NUM>°. The edge angle <NUM> can also differ considerably from said value, however. A region of the blade <NUM> which points away from the cutting edge has a run-out angle <NUM> which is <NUM>° in the present case, but the run-out angle <NUM> can also have other values. The run-out angle <NUM> is enclosed between the movement direction <NUM> and that region of the blade <NUM> which points away from the cutting edge. The run-out angle <NUM> avoids contact between the straps <NUM>, <NUM> to be severed and that region of the blade <NUM> which is arranged behind the cutting edge. The blade <NUM> is preferably made from a temperable steel material.

<FIG> shows a diagrammatic illustration of the strap end connecting device <NUM> in an operating position which corresponds to a first method step and in which the first fastening head <NUM> and the second fastening head <NUM> are moved together completely. The strap clamp <NUM> fixes the straps <NUM>, <NUM>. The first strap <NUM> is clamped in fixedly between the housing <NUM> of the first fastening head <NUM> and the strap clamp <NUM>. The second strap <NUM> is clamped in fixedly between the housing <NUM> of the second fastening head <NUM> and the strap clamp <NUM>. The heating element <NUM> and the blade <NUM> which is heated by way of heat radiation are in a starting position. The edge <NUM> of the blade <NUM> is spaced apart from the two straps <NUM>, <NUM>.

<FIG> shows the heating element <NUM> and the blade <NUM> in a partially extended operating position which corresponds to a following method step and in which the blade <NUM> severs the first strap <NUM>.

The first strap end 4a and the second strap end 4b of the first strap <NUM> are produced as a result. By way of further extension of the blade <NUM> in the movement direction <NUM>, the two strap ends 4a, 4b of the first strap <NUM> are oriented parallel to the movement direction <NUM> and spaced apart from one another, and are placed from the inside onto the strap clamp <NUM>.

<FIG> shows the heating element <NUM> and the blade <NUM> in a further following method step and a correspondingly largely extended operating position, in which the strap ends 4a, 4b of the first strap <NUM> are turned over completely and heated by means of the heating element <NUM>, and the blade <NUM> severs the second strap <NUM>. The first strap end 5a and the second strap end 5b of the second strap <NUM> are produced as a result.

In a further method step which is not shown in the figures, the first strap end 5a and the second strap end 5b of the second strap <NUM> are oriented parallel to the movement direction <NUM>, but in the opposite direction with respect to the strap ends 4a, 4b of the first strap <NUM> and spaced apart from one another, and are welded in each case to the associated strap ends 4a, 4b. To this end, the pusher <NUM> of the pressing unit <NUM> moves in the direction of the first fastening head <NUM> relative to the housing <NUM> of the second fastening head <NUM>, and places the strap ends 5a, 5b accordingly onto the associated strap ends 4a, 4b and presses against one another the strap ends 4a, 5a which bear against one another and the strap ends 4b, 5b which bear against one another, as a result of which they are welded in each case to one another.

Claim 1:
A strap end connecting device (<NUM>) for a strapping system (<NUM>), the strap end connecting device (<NUM>) being provided with two interacting assemblies, in particular with two fastening heads (<NUM>, <NUM>) which can be moved toward and away from one another, and which are provided for forming strappings from in each case two plastic straps, a separating device (<NUM>) for severing the two plastic straps and a welding unit (<NUM>) for welding strap ends (4a, 5a, 4b, 5b) of the two plastic straps being provided in a manner which is distributed to the two assemblies, wherein the strap end connecting device (<NUM>) comprises a separating device (<NUM>) for severing at least one strap (<NUM>, <NUM>), in particular a plastic strap, the separating device (<NUM>) has a blade (<NUM>) with an edge (<NUM>) for severing the at least one strap (<NUM>, <NUM>), and the separating device is adapted to be connected to the strap end connecting device (<NUM>), the strap end connecting device (<NUM>) has an assembly which has a heating element (<NUM>), wherein the blade (<NUM>) is adapted to be connected to that assembly of the strap end connecting device (<NUM>) which has the heating element (<NUM>), wherein the separating device (<NUM>) has a carrier (<NUM>), on which the blade (<NUM>) is arranged, the carrier (<NUM>) is adapted to be attached to that assembly of the strap end connecting device (<NUM>) which has the heating element (<NUM>) and characterized in that there is a spacing between the heating element (<NUM>) and the blade (<NUM>), wherein the heating element (<NUM>) is a constituent part of the welding unit (<NUM>) and wherein the blade is arranged in the vicinity of the heating element (<NUM>) by means of the carrier (<NUM>) such that the blade (<NUM>) can experience a temperature increase on account of the heating element (<NUM>), the strap end connecting device (<NUM>) further comprises an insulation means, by way of which the blade (<NUM>) is insulated electrically from the electrically heated heating element (<NUM>).