EP1711411B2 - Profile closing clip - Google Patents

Description

The invention relates to a closure clip (hereinafter also referred to as a clip) for closing tubular or bag-like, gathered packaging material with two legs connecting a clip plane and connected by a connecting section.

Such essentially U-shaped closure clips are well known. They are lined up for the purpose of magazining typically with parallel brackets levels in large numbers one behind the other to a kind of rod and fixed on the outside of the packaging section facing away from the packaging material by means of an adhesive or sealing strip, so that the clip bar is stabilized. For closing the packaging material, such a clip bar is transported perpendicular to the guideway of a displaceable punch of a Veschließeinrichtung and inserted with its front end in the guideway. The driven punch separates the foremost clip from the subsequent clips of the clip bar and transports it along its guideway until the legs of the clip engage around the packaging material in the area gathered to form a pigtail. On the last piece of the punch movement, the legs of the clip are bent under pressure against a die with a guideway in such a way that the clip surrounds the packaging material in a ring-shaped manner, the legs, in the closed state, being slightly removed from the clip plane, lying parallel next to one another.

The material strands or wires used for producing such closure clips-preferably metal wires and particularly preferably aluminum wires-are known to have different cross-sectional profiles.

From the DE 1 536 183 For example, a closure clip is known, the cross-sectional profile - starting from a round profile - oval to improve the weight-to-bending resistance ratio, wherein the height of the cross-sectional profile, ie the profile extent in the clip plane, determined by the large axis of the oval and thus greater than its width, so the profile extent perpendicular to the clip plane. Such a clamp requires less material than a closure clamp with a round cross-section with the same stability or, in other words, has a higher resistance moment with the same material requirement.

Also from the US 3,584,347 Staples are known whose cross-sectional profiles have a lying in the staple plane main extension direction. Unlike the oval clip but whose inner width, ie the width of the closure clip on the side to be closed / closed packaging envelope facing side, larger than its outer width.

This cross-sectional profile is based on the endeavor to increase the bending stiffness with the least possible use of material. In addition there are further requirements influencing the clip profile, such as the guidance of the closure clip in the guideway and the die, a slip-resistant inner surface or an inner surface with rounded edges to avoid injuries to the packaging wrapper to be closed.

In the DE OS 1 959 755 occurs the effort of saving material at the same moment of resistance also evident that the tapering of the cross-sectional profile of the closure clip disclosed there takes place from the larger inner to smaller outer width on side grooved recesses.

US 3,541,647 discloses a closure clip according to the preamble of claim 1. The object is to provide a closure clip with a further improved locking force at the same cost of materials that is easy to manufacture and magazineable.

This object is achieved by a closure clip of the type mentioned with the features of the characterizing part of claim 1. For example, to achieve a completely airtight seal, very strong radially inwardly directed compressive forces must act on the packaging material in the area gathered to form a pigtail and firmly compress the material, which is especially true for plastic films.

For this purpose, the cross-sectional profile of the material strand forming the clip according to the invention preferably points laterally over the entire length of the clip, i. the width of the clip limiting profile edges, one of which has a recess and the other has a projection. The projection and the recess are dimensioned so that they can interlock in the closed state of the clip. Thus, when closing a positive connection ("toothing") between the two folded, parallel juxtaposed legs of the clip can be achieved. The radially outward pressure forces, which opposes the packaging material to the clip, are prevented in this way from spreading the clip again. With the profiling of the clip material according to the invention, therefore, in addition to the material savings with constant bending stiffness, which formed the focus of optimization in the known clips, another feature increasing the locking force is provided by which, however, no noteworthy losses with regard to the material savings achieved are accepted have to.

It should be noted at this point that the cross-sectional profile for manufacturing reasons, preferably over the entire length of the closure clip is uniform. The invention is, however, not limited thereto. In particular, the improved locking force can be achieved even if the claimed profiling only on the range of Limb is limited.

According to an advantageous embodiment, the projection has a convex radius and the recess has a concave radius of the same size. As a result, the positive connection can be improved.

It is advantageous if the height of the cross-sectional profile (profile extent in the clip plane) is greater than its width (profile extent perpendicular to the clip plane). With increasing height of the profile, the moment of resistance increases in the square, so that at a corresponding ratio of height to width a desired, decisive for the locking force resistance torque is achieved with the least possible use of materials. In particular, the cross-sectional profile preferably has a height which is greater by 1/3 to 1/2 than the width.

Fig. 1A

eine Vorderansicht einer offenen Verschlussklammer;

Fig. 1B

eine Seitenansicht der offenen Verschlussklammer gemäß Fig. 1A;

Fig. 2A

eine Vorderansicht einer Ausführungsform der verschlossenen Verschlussklammer;

Fig. 2B

einen Schnitt durch die verschlossene Verschlussklammer gemäß der Ausführungsform aus Fig. 2A;

Fig. 3A

eine Vorderansicht einer ersten Ausführungsform der erfindungsgemäßen, verschlossenen Verschlussklammer;

Fig. 3B

einen Schnitt durch die verschlossene Verschlussklammer gemäß der Ausführungsform aus Fig. 3A;

Fig. 3C

einen Schnitt durch die verschlossene Verschlussklammer gemäß der Ausführungsform aus Fig. 3A mit verdrehten Schenkeln;

Fig. 4A

eine Vorderansicht einer zweiten Ausführungsform der erfindungsgemäßen, verschlossenen Verschlussklammer; und

Fig.4B

einen Schnitt durch die verschlossene Verschlussklammer gemäß der Ausführungsform aus Fig. 4A.

These and other objects, features and advantages of the invention will now be explained in more detail by means of exemplary embodiments with the aid of the drawings. Show it:

Fig. 1A

a front view of an open closure clip;

Fig. 1B

a side view of the open closure clip according to Fig. 1A ;

Fig. 2A

a front view of an embodiment of the closed closure clip;

Fig. 2B

a section through the closed closure clip according to the embodiment of Fig. 2A ;

Fig. 3A

a front view of a first embodiment of the invention, closed closure clip;

Fig. 3B

a section through the closed closure clip according to the embodiment of Fig. 3A ;

Fig. 3C

a section through the closed closure clip according to the embodiment of Fig. 3A with twisted thighs;

Fig. 4A

a front view of a second embodiment of the invention, closed closure clip; and

4B

a section through the closed closure clip according to the embodiment of Fig. 4A ,

The aforementioned closure clip 100 typically has the in Fig. 1A and 1B illustrated U-shaped initial shape before sealing the packaging material. Two legs 110 and 112 pass over radii in a connecting portion 114 connecting them. The closure clip 100 may be made of various materials such as steel and aluminum. It is preferably made of a straight strand of material in the in Fig. 1A bent figure shown bent.

The legs 110, 112 each have a chamfer 116 or 118 on its outer side 120, which serves to control the deflection of the legs when closing the clip in the die and to let go with minimal friction. The two legs define a clip plane, shown as a dotted line 122 in FIG Fig. 1B is drawn. The width of the clip is determined by two spaced side surfaces 124 and 126 parallel to the clip plane.

Fig. 2A shows an embodiment of the clip 200 in the closed, the shirred portion of a packaging material (not shown) embracing shape. The two legs 210 and 212 are parallel here and at the same height next to each other (in this illustration, one behind the other). The peculiarity of the clip according to the invention is first in the in Fig. 2B shown sectional view of this embodiment recognizable. The section shows that the cross-sectional profile 230 (shown hatched) of the material strand forming the clip has lateral, ie formed by the side surfaces 224, 226 profile edges, each having a first projection 232 and 234 and a second projection 242 and 244 between each of which a recess 252 and 254 is included.

The cross-sectional profile of this embodiment is designed (in the undeformed shape) mirror-symmetrical to the bracket plane 222. A mirror-symmetrical profile has the advantage that when bending the legs no bending or tilting moments pointing out of the bracket plane occur, which can lead to problems when closing the clip. Furthermore, it is not important to magazine the locking device on the orientation of the clip or the clip bar.

Due to the symmetry, the projections 232, 234 and 242, 244 and recesses 252, 254 are opposite the two sides of the profile. Thus, a positive connection does not occur when the clip, as in FIGS. 2A and 2B can be seen, when closing is bent so that the legs 210, 212 are arranged parallel to each other at the same height. In this transformation, the clamping force of the clip according to the invention, alone determined on the bending stiffness or moment of resistance. In this regard, that is in FIG. 2B However, shown cross-sectional profile optimized. In particular, the height of the cross-sectional profile is advantageously greater than its width, since the moment of resistance increases quadratically with increasing height of the profile. In the most preferred height-to-width ratio from 1 1/3: 1 to 1.5: 1, an optimum ratio between the moment of resistance and the material used is achieved. This basically rectangular cross-sectional geometry and the mentioned aspect ratio results in approximately twice the clamping force on the braid as in a round, uniform cross-section.

The ratio of moment of resistance and material use is additionally improved by the lateral recesses. These are provided in this embodiment particularly advantageous in the region of the neutral zone, which is neither compressed nor stretched during the forming.

The width of the projections 232, 234, 242, 244 (extension of the projections parallel to the clip plane) in this embodiment is less than the width of the recesses 252, 254. Therefore, they are suitable to engage in the closed state of the clip 200 into one another and so on To ensure positive engagement. For this, the clip, as in Figs. 3A to 3C can be seen, are bent in such a way during closing in a die, that the legs 310, 312 are parallel to each other but offset in height to each other. The first projection 334 of the one lateral profile edge of the second leg 312 then engages in the recess 352 of the opposite lateral profile edge of the first leg 310. Conversely, in this profile, the second projection 342 of the one side profile edge of the first leg 310 engages in the recess 354 of the opposite lateral profile edge of the second leg 312. The double teeth thus obtained provides increased security against the spreading of the closed clip. The recesses 352, 354 have a double function in this case, namely material savings on the one hand and positive fit on the other.

The clip takes on a more space-saving design in this type of closure, since the width of the closed clip is reduced compared to the sum of both leg widths by the depth of the recesses (expansion of the recesses in the direction perpendicular to the clip plane).

In contrast to the embodiment according to Fig. 2 is according to the invention in the example Fig. 3 the width of the projections and recesses, ie their extension parallel to the plane of the bracket, identical. More specifically, the protrusions have a convex radius and the recesses have a concave radius of equal size. This contributes to a twisting of the legs caused during closing: Since a lateral offset of the legs from the bracket plane must take place when the clip is closed, so that they come to lie next to one another, the material strand is twisted in the region of the connecting section 314 and the bends 316, 318 , As a result, the cross-sectional profile in the region of the legs 310, 312 is also rotated relative to the plane of the bracket by a small angle α about the center axis of the material strand, as in FIG Fig. 3C is exaggerated. However, due to the same radii of the projections and the recesses, the positive connection remains independent of the angle α.

Both embodiments Fig. 2 and Fig. 3 is common that in each case both lateral profile edges first projections 232, 234, 332, 334 and second projections 242, 244, 342, 344, between which the recesses 252, 254, 352, 354 are included. The first protrusions 232, 234, 332, 334 respectively merge into the inner surface 260, 360 facing the packaging material and the second protrusions 242, 244, 342, 344 extend into the outer surface 270, 370 of the closure clip 200, 300 facing away from the packaging material. As a result, the width of the clips in the area of the inner surface (inner width) and outer surface (outer width) is the largest.

In addition to the above-mentioned advantages, this "double T-profile" has the further advantage of lower susceptibility to interference: indeed, all the corners present on the profile are rounded in order to avoid damaging the packaging material. Preferably, the outer surface 270, 370 at least in the region of the connecting portion 214, 314 but transitional edges with both side profile edges forming side surfaces 224, 226, 324, 326, wherein the transition edges have radii which are less than or equal to 0.5 mm. (Thus, the larger radius of the projections does not extend tangentially into the outer surface.) Such "sharp" transition edges prove to be advantageous in that, in cooperation with the punch driven along its guideway, they affix the adhesive or sealing strip which clips the clips Rod fixed, shear when separating the foremost clip and thus secure process separation.

Further, in a closure clip having such a cross-section with a large outer width, the outer surface can be used for a codification or other embossing with a characteristic or technical-functional purpose. For example, for better guidance of the closure clip by the punch during the closing operation on the outer surface of the clip, an approximately triangular, extending in the longitudinal direction of the material strand groove are mounted, in which engages the punch.

Due to the large inner width of the cross-sectional profile, the sealing effect of the clip is significantly improved. Furthermore, there is enough space available on the inner surface of the clip to attach imprints with a technical purpose. For example, in an advantageous embodiment, the inner surface can be provided with at least one notch or groove in the longitudinal direction of the material strand. As a result, the risk of slipping of the closed clip of the packaging material, in particular plastic film is reduced.

In the FIGS. 4A and 4B a further embodiment of the clip 400 according to the invention is shown, which has a cross-sectional profile which is not mirror-symmetrical to the clip plane 422 but point-symmetrical to the center 423 of the profile. A clip with this profile can be closed so that the legs 410, 412 are parallel to each other without height offset, yet a positive connection is achieved because the projection 432 of a side profile edge of the recess 454 in the other side profile edge is opposite and vice versa. The advantage is that in this form of positive engagement and thus an increased clamping force and a space-saving shape can be achieved while both legs in the closed state of the shirred packaging material (not shown) bear, thereby simultaneously an even safer sealing of the packaging and adhesion given to the braid.

Also in the embodiment according to Fig. 4 the projections and recesses are provided with the same radii, so that the positive connection is ensured even with axially twisted legs.

Finally, it should be noted that neither the number of protrusions nor that of the recesses is fixed to that of the exemplary embodiments. Also, the shape or arrangement (symmetry) of the projections and recesses is not limited to the examples shown.

Claims (6)

1. A closure clip (200, 300, 400) for closing tubular or bag-like, gathered packaging material, comprising two limbs (110, 112, 210, 212, 310, 312, 410, 412) which define a clip plane (122, 222, 422) and which are connected by a connecting portion (114, 214, 314), wherein
   the closure clip is formed from a piece of material having a cross-sectional profile (230) with lateral profile edges which delimit the width of the cross-sectional profile (the extent of the profile perpendicularly to the plane of the clip) and of which one profile edge has a recess (252, 254, 352, 354, 454) and the other profile edge has a projection (232, 234, 332, 334, 432), wherein the projection and the recess are capable of engaging into each other in the closed condition of the closure clip,
   characterised in that the projection (232, 234, 331, 334, 432) has a convex radius and the recess has a concave radius (252, 254, 352, 354, 454) of equal size.
2. A closure clip (200, 300) according to claim 1,
   characterised in that both lateral profile edges each have a first projection (232, 234, 332, 334) and a second projection (242, 244, 342, 344) between which the recess (252, 254, 352, 354) is enclosed.
3. A closure clip (200, 300) according to claim 2,
   characterised in that the cross-sectional profile (230) is in mirror-image symmetrical relationship with the clip plane (222).
4. A closure clip (200, 300) according to one of the preceding claims,
   characterised in that at least in the region of the connecting portion (214, 314) an outside surface (270, 370) of the closure clip (200, 300), which is remote from the packaging material, forms transitional edges with the side surfaces (224, 226, 324, 326), which form the lateral profile edges, wherein the transitional edges are of radii which are less than or equal to 0.5 mm.
5. A closure clip at least according to claim 1,
   characterised in that an inside surface (260, 360) of the closure clip (200, 300), which is towards the packaging material, has at least one notch in the longitudinal direction of the piece of material.
6. A closure clip at least according to claim 1,
   characterised in that the height of the cross-sectional profile (the extent of the profile in the plane of the clip) is greater than its width (the extent of the profile perpendicularly to the plane of the clip).

Images