EP1050462B1 - Tensioning unit for a strapping machine - Google Patents

Abstract

The tensioning unit (10) has a tensioning-head (20) contained in a housing (22). The tensioning-head comprises a tensioning appliance (24). a clamping and closure unit (26). The housing has a web-guide divided into a back and front (40',40) part and positioned behind the clamping and closure unit in the web's direction of travel. Only the front web-guide part, together with t tensioning head is movable in relation to the housing. The back web guide part is movable away across the direction of the web's travel (B) and preferably against spring force, by means of the front web-guide part moved in the web's direction of travel.

Description

The invention relates to a tensioning unit for a strapping machine for tensioning and closing a led around a material Band, with a clamping head and a receiving this Housing, the clamping head a clamping device and a clamping and Closure unit includes and towards the end of a respective tensioning process in a tape running direction opposite to the tensioning direction is displaceable relative to the housing, and wherein a in Belt running direction arranged behind the clamping and closing member Band guide is provided.

By means of such a tensioning unit, the belt is usually first in introduced a strapping of the strapping machine and so led around the respective strapping material. Then that will Band end clamped by means of the clamping and closing member. Before the band is tensioned by means of the tensioning device, are provided Tape guides moved back to release the tape. Subsequently the band is tensioned by the tensioning device, with the different Corners of the strapping friction occurs. after the Belt tension due to this friction from corner to corner of the strapping material decreases, the clamping head is in towards the end of the clamping process a tape running direction opposite the tensioning direction relative to this clamping head receiving housing moved to for a corresponding To ensure voltage equalization. Here is the strapping material fixed with respect to the housing, for example the housing fixed be connected to the strapping of the strapping machine can.

In the case of the tensioning units which have been customary to date, it is not only the direction of travel of the strip tape guide arranged behind the clamping and closing element, but also the entire rear belt guide with the tensioning head shifted relative to the housing in the tape running direction.

After with each movement of the clamping head in this Tension direction opposite tape running direction also the entire rear Band guide is moved accordingly and this rear The tape guide must have enough space to emerge from the housing To be able to, the housing must have an appropriate Passage be provided. Appropriate interventions in the tape guide bend connected to the housing is required.

The invention has for its object a clamping unit of the beginning to create the type mentioned, on the previously required housing passages can be dispensed with and consequently without any intervention the adjacent components can be installed.

This object is achieved in that the behind the clamping and closing member arranged tape guide in a front and a rear band guide part is divided so that only the front Band guide part together with the tensioning head relative to the housing is displaceable and that the rear band guide part by the in The tape running direction preferably moves in the opposite direction a spring force generally movable away from the tape running direction is.

Each time the clamping head is moved, the rear one Band guide part through the front band guide part thus inside the housing generally pushed away transversely to the tape running direction, whereby space for movement of the front belt guide part within the housing is created. The rear belt guide part makes the movement of the tensioning head in the tape running direction. In the case no more passages are required. The clamping unit can without interfering with the adjacent components in the strapping machine in question to be built in. This is particularly the case when installing an advantage in existing machines.

The front and rear tape guide part can in particular with interacting inclined surfaces over which the rear Band guide part is pushed away accordingly. Will the chuck and thus the front tape guide part is moved in the tape running direction, the rear belt guide part slides along with its inclined surface the inclined surface of the front band guide part, for example outwards, which creates space for the front band guide part becomes.

In an expedient practical embodiment of the invention Tensioning unit is the rear band guide part around one on the housing supported inner axle pivoted and by a spring force loaded into his tape guide position. Should the tape for the Tensioning process can be released, so the rear band guide part are deflected accordingly against the spring force. Then becomes against At the end of the tensioning process, the tensioning head is moved in the direction of the belt travel, can this rear band guide part against the spring force are also deflected to make room for the front belt guide part to accomplish. The pivot axis in question preferably extends generally parallel to the tape running direction.

That which is preferably arranged at a free end of a pivot lever rear tape guide part can in particular with a tape guide slot be provided. As soon as this tape guide part from its tape guide position is swung out, the tape can be removed from the guide slot stepping out.

In a preferred practical embodiment of the invention Tensioning unit is the front one for each release of the belt Belt guide part can be driven, while the rear belt guide part from front tape guide part is taken accordingly. The rear Tape guide part is thus already for a respective tape release from front band guide part acted accordingly.

The front band guide part can, for example, about an axis pivotally mounted and by a spring force in its tape guide position be burdened. The pivot axis expediently extends again generally parallel to the tape running direction.

Also preferably arranged at a free end of a pivot lever front tape guide part is expedient again with a Band guide slot provided. This is conveniently with aligned with the guide slot of the rear tape guide part. Becomes now the rear belt guide part for a respective release of the belt for example, carried along by the front band guide part and accordingly pivoted with this, the band is simultaneously by released both slots.

In an expedient practical embodiment of the invention The tensioning unit is preferably with a tape guide slot provided front tape guide part at a free end of a two-armed Arranged pivot lever, at the other free end with a cam roller interacting follower roller is provided. there the swivel lever can be returned to the tape guide position by spring force be burdened.

As a rule, the tensioning head is also positioned in front of the belt Clamping and closure member arranged tape guide. Also such a front tape guide is then for a respective release of the The tape can preferably be moved out of its tape guide position.

Fig. 1

eine schematische Seitenansicht einer mit einer erfindungsgemäßen Spanneinheit versehenen Umreifungsmaschine,

Fig. 2

eine schematische Draufsicht der Spanneinheit, wobei der Spannkopf in seiner Ausgangsposition dargestellt ist und die Bandführungen jeweils ihre Bandführungsposition einnehmen,

Fig. 3

eine schematische Draufsicht der Spanneinheit, wobei der Spannkopf weiterhin seine Ausgangsposition einnimmt, die Bandführungen jedoch bereits aus ihrer jeweiligen Bandführungsposition herausbewegt sind,

Fig. 4

eine schematische Draufsicht der Spanneinheit, wobei der Spannkopf bereits aus seiner Ausgangsposition heraus in die der Spannrichtung entgegengesetzte Bandlaufrichtung verschoben wurde und das hintere Bandführungsteil entsprechend durch das vordere Bandführungsteil der hinteren Bandführung zusätzlich nach außen weggedrängt ist,

Fig. 5

eine schematische Seitenansicht des der hinteren Bandführung zugeordneten vorderen Bandführungsteils, in Bandlaufrichtung betrachtet,

Fig. 6

eine schematische Vorderansicht des vorderen Bandführungsteils,

Fig. 7

eine schematische Seitenansicht des der hinteren Bandführung zugeordneten hinteren Bandführungsteils, in Bandlaufrichtung betrachtet,

Fig. 8

eine schematische Vorderansicht des hinteren Bandführungsteils und

Fig. 9

eine Prinzipskizze zur Wirkungsweise der Spanneinheit beim Spannen.

The invention is explained below using an exemplary embodiment with reference to the drawing; in this show:

Fig. 1

2 shows a schematic side view of a strapping machine provided with a tensioning unit according to the invention,

Fig. 2

2 shows a schematic top view of the tensioning unit, the tensioning head being shown in its starting position and the tape guides each assuming their tape guide position,

Fig. 3

2 shows a schematic top view of the tensioning unit, the tensioning head still assuming its starting position, but the tape guides have already been moved out of their respective tape guide position,

Fig. 4

2 shows a schematic plan view of the tensioning unit, the tensioning head having already been displaced from its initial position in the direction of tape travel opposite to the tensioning direction and the rear tape guide part being additionally pushed outwards by the front tape guide part of the rear tape guide,

Fig. 5

FIG. 2 shows a schematic side view of the front tape guide part assigned to the rear tape guide, viewed in the tape running direction,

Fig. 6

a schematic front view of the front tape guide part,

Fig. 7

FIG. 2 shows a schematic side view of the rear tape guide part assigned to the rear tape guide, viewed in the tape running direction,

Fig. 8

is a schematic front view of the rear tape guide part and

Fig. 9

a sketch of the principle of operation of the clamping unit during clamping.

Fig. 1 shows a purely schematic side view of one with an inventive Tensioning unit 10 provided strapping machine 12 with a the transfer sheet 16 encompassing the respective strapping material 14.

The tensioning unit is used to tension and close one around the material 14 led around band 18, which is for example can be a plastic band. The clamping unit 10 has one Clamping head 20 and a housing 22 accommodating the same, which in the present case Case is supported on the transfer sheet 16. The front bypass bow 16 surrounding strapping material 14 is with respect to the housing 22 of the clamping unit 10 fixed in its position.

The clamping head 20 comprises a clamping device 24 and a clamping and Closure unit 26. The tensioning device 24 serves in particular the final tensioning of the band 18. Between the tensioning device 24 and the clamping and locking assembly 26 is a with a reversible Drive connected conveyor roller pair 28 arranged. It's about it determined by an unwinder 30 via a tape guide unit 31 supplied and passed through the clamping device 24 Belt 18 in a belt running direction opposite to the tensioning direction S. B through the clamping and locking assembly 26 and with to shoot into the bypass bend 16 'ahead of the free band end 18', until the band end 18 'at a stop in the clamping and closing assembly 26 is coming. The transfer sheet 16 runs around the strapping material 14 around. In addition, the pair of conveyor rollers 28 is intended the led around the strapping 14 and by means of a first Band clamp 32 of the clamping and sealing assembly 26 at a distance clamped to the band end 18 'at the abovementioned stop Retract band 18 in tension direction S until at least is essentially applied to the strapping material 14.

The clamping and closing assembly 26 has a second band clamp 34 and a welding unit 36 between the two band clamps 32, 34 (Compare in particular Fig. 2 to 4), for example with a Welding tongue or the like can be provided.

After the pair of conveyor rollers withdrawn the belt 18 in the tensioning direction S. and this has put on the strapping material 14, the Tensioning device 24 in operation, whereby the band 18 is gripped and opened the predetermined clamping force is tensioned.

As can be seen from the schematic diagram according to FIG. 9, through the Tensioning the strap 18 at each corner of the strapping material 14 friction on. From corner a over corners b and c to corner d of the strapping material 14 the tape tension decreases. Order now for a corresponding To ensure voltage equalization, the clamping head 20 is against End of each tensioning process in the direction opposite to the tensioning direction S. Tape running direction B with the tape end 18 'clamped relative moved to the housing 22 to the left. The clamping head 20 by guides 37 fixed to the housing in FIGS. 2 to 4 ' guided.

Following this, the clamping and closing assembly 26 comes into operation, by the second band clamp 34 clamping the band 18 and the Welding unit 36 (compare FIGS. 2 to 4) the two each other overlapping portions of the band 18 by heating and clamping welded together. Then by means of the clamping and locking unit 26 the band 18 seen in the tensioning direction S downstream severed the weld.

As can be seen in particular from FIGS. 2 to 4, the Clamping head 20 in the tape running direction B in front of the clamping and closing member 26 arranged tape guide 38, which together with the Clamping head 20 is displaceable relative to the housing 22.

In the housing 22 is also one in the tape running direction B behind the Clamping and closure member 26 arranged band guide 40 is provided.

As can best be seen again with reference to FIGS. 2 to 4, the band guide 40 arranged behind the clamping and closing member 26 viewed in a tape running direction B front and rear tape guide part 40 'or 40 "divided. Here is only the front tape guide part 40 'together with the clamping head 20 relative to the housing 22 displaceable. In contrast, the rear tape guide part 40 "by in the tape running direction B moved front tape guide part 40 'against Force of a return spring 42 (see FIG. 7) generally transverse to the tape running direction B moved away (compare in particular Fig. 4). As in Fig.4 can be removed, such a pushing away of the rear Tape guide part 40 "after release of the tape 18. This means that the rear tape guide member 40 "with a respective shift of the clamping head 20 further outwards, in FIG below, is moved as with the previous release of the tape 18 is already the case. It is therefore essential that the rear band guide part 40 "relative to the front tape guide part 40 'transversely to the tape running direction B is moved so that 22 space inside the housing is created for the movement of the front band guide part 40 '. The rear band guide part 40 "thus makes the movement of the tensioning head 20 in the tape running direction B not with. Accordingly, in the housing 22 also no longer required passages, which means that the Clamping unit 10 without interventions in the adjacent components such as the transfer sheet 16 installed in the strapping machine 12 can be. This is especially true when installing in existing machines are an advantage.

In the following case, the front and rear tape guide members 40 ' or 40 "with interacting inclined surfaces 44, 46, about the rear band guide member 40 "in that shown in FIG. 4 Is pushed outwards accordingly.

In the present embodiment, the rear band guide part 40 "pivotally mounted about an inner axis 48 supported on the housing 22, which extends generally parallel to the tape running direction B. (Compare in particular FIGS. 7 and 8). This is due to the free Rear band guide part 40 ″ arranged at the end of a pivot lever 50 provided with a tape guide slot 52. The return spring 42 is arranged between the housing 22 and the pivot lever 50. By this return spring 42 is the pivot lever 50 in the tape guide position loaded in the band 18 in the guide slot 52 is. As can be seen from FIG. 7, the rear band guide part 40 "then to release the tape 18 or beyond for release the displacement path for the front tape guide part 40 ' the force of the return spring 42 can be pivoted accordingly.

The front tape guide part is for a respective release of the tape 18 40 'drivable, while the rear tape guide part 40 "from the front Band guide part 40 'is taken accordingly (see in particular FIGS. 2 and 3).

As can best be seen from FIGS. 5 and 6, the front one is Band guide part 40 'pivotally mounted about an axis 54 and through the force of a return spring 56 loaded into its tape guide position. The pivot axis 54 again runs generally parallel to the tape running direction B.

In the following embodiment, this is again with a tape guide slot 58 provided front band guide part 40 'on a free End of a two-armed pivot lever 60 arranged on the other free end of a follower roller cooperating with a cam 62 64 is provided (compare in particular FIGS. 5 and 6).

For a respective release of the band 18, the pivot lever is thus 60 pivoted about the cam 62 accordingly, whereupon the Band 18 from the guide slot 58 of this pivot lever 60 assigned front tape guide part 40 'emerges. The rear band guide part 40 "is carried along by the front band guide part 40 ', so that with a pivoting of the front band guide part 40 ' from the tape guide position also the rear tape guide part 40 "is pivoted accordingly and the belt 18 at the same time from the tape guide slot 52 of this rear tape guide part 40 " emerges.

The front band guide 38 is also for a respective release of the band 18 movable out of its tape guide position.

Claims (12)

1. Tensioning unit (10) for a strapping machine (12) for tensioning and closing a band (18) which is guided around an article which is to be strapped (14), having a tensioning head (20) and a housing (22) accommodating the same, wherein the tensioning head (20) comprises a tensioning arrangement (24) and a clamping and closure subassembly (26) and, towards the end of a respective tensioning operation, can be displaced relative to the housing (22) in a band-running direction (B) counter to the tensioning direction, and wherein a band guide (40) arranged downstream of the clamping and closure subassembly (26), as seen in the band-running direction (B), is provided in the housing (22), characterized in that the band guide (40), which is arranged behind the clamping and closure subassembly (26), is subdivided into a front and a rear band-guiding part (40' and 40", respectively), in that only the front band-guiding part (40') together with the tensioning head (20) can be displaced relative to the housing (22), and in that the rear band-guiding part (40") can be moved away generally transversely to the band-running direction (B), preferably counter to a spring force (42), by the front band-guiding part (40') moving in the band-running direction (B).
2. Tensioning unit according to Claim 1, characterized in that the front and the rear band-guiding parts (40' and 40", respectively) are provided with interacting oblique surfaces (44, 46), via which the rear band-guiding part (40") is correspondingly forced away.
3. Tensioning unit according to Claim 1 or 2, characterized in that the rear band-guiding part (40") is mounted such that it can be pivoted about an inner pivot axle (48) supported on the housing (22), and it is biased into its band-guiding position by a spring force (42).
4. Tensioning unit according to Claim 3, characterized in that the pivot axle (48) generally extends parallel to the band-running direction (B).
5. Tensioning unit according to one of the preceding claims, characterized in that the rear band-guiding part (40"), which is preferably arranged at a free end of a pivot lever (50), is provided with a band-guiding slot (52).
6. Tensioning unit according to one of the preceding claims, characterized in that, for a respective release of the band (18), the front band-guiding part (40') can be driven and the rear band-guiding part (40") is correspondingly carried along by the front band-guiding part (40').
7. Tensioning unit according to one of the preceding claims, characterized in that the front band-guiding part (40') is mounted such that it can be pivoted about a pivot axle (54), and is biased into its band-guiding position by a spring force (56) .
8. Tensioning unit according to Claim 7, characterized in that the pivot axle (54) generally extends parallel to the band-running direction (B).
9. Tensioning unit according to one of the preceding claims, characterized in that the front band-guiding part (40'), which is preferably arranged at a free end of a pivot lever (50), is provided with a band-guiding slot (58).
10. Tensioning unit according to one of the preceding claims, characterized in that the front band-guiding part (40'), which is preferably provided with a band-guiding slot (58), is arranged at one free end of a two-armed pivot lever (60), a follower roller (64) interacting with a cam plate (62) being provided at the other free end of said pivot lever.
11. Tensioning unit according to one of the preceding claims, characterized in that the tensioning head (20) also comprises a band guide (38) arranged upstream of the clamping and closure subassembly (26), as seen in the band-running direction (B).
12. Tensioning unit according to Claim 11, characterized in that the front band guide (38), for a respective release of the band (18), can be moved out of its band-guiding position.

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