EP0075501B1 - Locking tie - Google Patents

Abstract

A cable tie comprises a strap having a series of transverse teeth on one side extending between the longitudinal edges thereof, and a fastening head having a passageway therethrough for receiving the strap to form a loop. The fastening head has a pawl cooperable with the strap teeth. The longitudinal edges of the strap are at least in part transversely oblique and each of the corresponding lateral walls of the passageway are similarly transversely oblique. The transversely oblique edge portions on the strap converge to the side of the strap away from the side having the teeth so that the pawl produces a wedging effect to clamp the strap transversely between the lateral wall portions of the passageway. Also, the lateral wall portions of the passageway converge toward each other in a direction away from the pawl. The oblique portions are preferably surface roughened.

Description

The present invention relates generally to collars, commonly known as clamps, of the type used for example to ensure the connection between them of a bundle of cables in any electrical installation, and / or to ensure , in any equipment, the subjugation to any support of such a bundle of cables or of one or more other members.

It relates more particularly to those of these clamps which comprise, in one piece, on the one hand a flexible strap, which has transversely, on at least one of its faces, between its two longitudinal edges, a series of notches, and, on the other hand, a closing head, which has a passage suitable for the engagement of said flexible strap, for closing, in a loop, on itself, thereof, and which is equipped with a clean pawl to cooperate in retention with the notches of said flexible strap.

As regards for example the connection between them of a bundle of cables, the flexible strap of such a clamp is passed around this bundle before being engaged in the passage of its closing head.

It is then subjected to traction, either manually or, more often than not, using a clamp suitable for this purpose, to ensure the desired tightening of the cables concerned.

During this traction, the pawl elastically escapes, notch by notch, from the notches of the flexible strap, in the manner of the pawl of a ratchet wheel.

At the end of this traction, that is to say when it is released, the pawl, which is elastically articulated to the closing head which it equips, is buckled on one or more of the notches of the flexible strap, and, thus opposing any retrograde movement thereof, it maintains the closed loop under tension of the assembly around the cable harness concerned.

The security of the assured tightening is conditioned, on the one hand by the tensile strength of the flexible strap, and in particular of the rooting area of the latter at the closure head, and on the other hand by the resistance to the pulling of the fastening secured to the right or ratchet.

In practice, the latter is usually to date less than the inherent tensile strength of the closure strap, and it is therefore it which truly conditions, for a given clamp, the security of the clamping ensured by it .

Most often, the longitudinal edges of the flexible strap are mutually parallel, perpendicular to the longitudinal faces of this flexible strap, so that the cross section of the latter is generally rectangular, and the same is true for the corresponding walls of the passage of the closing head.

As a result, it is against a wall of this passage opposite the pawl that the latter applies, in the closed position, the flexible strap.

This is the case, for example, in document FR-A 2.100.502, in which, in addition, said wall d _3, its passage being continuous, the closing head is closed on itself.

Certainly, in US Patent No. 2,977,145, the longitudinal edges of the flexible strap are transversely oblique to each other, and the same is true for the corresponding walls of the passage of the closure head.

However, in this American patent, the longitudinal edges of the flexible strap come transversely towards one another in the direction of the face of said flexible strap having the notches suitable for cooperating with the corresponding pawl, without, moreover, that the reasons for such a provision be explained.

It follows that, as before, it is against the wall of the passage of the closing head opposite the pawl, or bottom wall, that this pawl, in the closed position, applies the flexible strap.

In document BE-A 847.500, the longitudinal edges of the flexible strap are partly transversely oblique with respect to each other, approaching transversely from one another in the direction opposite to the face of said strap flexible having the proper notches to cooperate with the corresponding pawl, and the passage of the closing head comprises, in correspondence with the parts thus transversely oblique one with respect to the other of said longitudinal edges of the flexible strap, two lateral walls which, on at least part of their dimensions, are similarly transversely oblique with respect to each other.

As before, the reasons for such a provision are not explained.

In addition, in this document BE-A 847.500, the closing head is open by a slot, for engagement of the flexible strap from the side, so that it is necessary to provide between it and said flexible strap means of 'own hooking to allow its locking by the latter.

Without the support conditions of the flexible strap under the stress of the pawl being specified, there is every reason to believe that, as before, and moreover as shown, this support is made on the flat part of the wall concerned with the passage of the closure head on either side of its slot; otherwise, the attachment means provided between the closure head and the flexible strap for locking it could fail in their function.

The present invention generally relates to a different arrangement, which proves advantageously to lead to a higher tensile strength for the closure ensured at right click.

More specifically, it relates to a clamp of the kind comprising, in one piece, on the one hand a flexible strap, which has transversely, on at least one of its faces, between its two longitudinal edges, a series of notches, and on the other share a closing head which has a passage suitable for the engagement of said flexible strap, for closing, in a loop, on itself, of the latter, and which is fitted with a pawl suitable for cooperating in retention with the notches of said flexible strap, said longitudinal edges of said flexible strap being at least partially transversely oblique with respect to each other, approaching transversely from one another in the direction opposite to the face of said strap flexible having the notches suitable for cooperating with said pawl and the passage of the closure head comprising, in correspondence with the parts thus transversely oblique to one another of the longitudinal edges of the flexible strap, two side walls which, on a e part at least of their dimensions, are similarly transversely oblique to each other (BE-A-847 500) this clamp being characterized in that the closure head is closed on it -same, so that it develops, by wedge effect, under the bias of the pawl, a transverse pinching of said flexible strap between the corresponding side walls of said passage of the closure head, with a clearance remaining ( J) between the inner face of the flexible strap, on the one hand, and the corresponding transverse wall of the passage of the closure head, on the other hand.

Thanks to this wedge effect, which is not found in any of the above documents, the tensile strength of the closure then ensured by the pawl together with the support, under the stress of the latter, of the flexible strap against the corresponding walls of the passage of the closure head, is found, the conditions being equal, significantly improved, and therefore significantly increased, in the same proportions, the overall clamping capacity of the clamp concerned.

According to the invention, to further increase this tensile strength, it is proposed to increase the friction between the flexible strap and the corresponding walls of the passage of the closure head.

To this end, and according to the invention, the transversely oblique parts relative to each other of the longitudinal edges of the flexible strip, at least, are granitized, for example by electro-erosion, and / or it is similarly, at least, for the transversely oblique parts with respect to each other of the side walls of the passage of the closure head.

• la figure 1 est, avec un arrachement local, une vue en élévation d'un collier de serrage suivant l'invention; .
• la figure 2 reprend, à échelle supérieure, le détail de la figure 1 repéré par un encart Il sur celle-ci;
• la figure 3 est, à l'échelle de la figure 2, une vue en coupe transversale du collier de serrage suivant l'invention, suivant la ligne III-III de la figure 2:
• la figure 4 reprend, à échelle supérieure, et avec un arrachement local, le détail de la figure 1 repéré par un encart IV sur celle-ci;
• la figure 5 est, à l'échelle de la figure 4, une vue partielle en plan du collier de serrage suivant l'invention, suivant la flèche V de la figure 4;
• les figures 6 et 7 sont des vues partielles en perspective de ce collier de serrage, suivant respectivement les flèches VI et Vll de la figure 5;
• la figure 8 est une vue en élévation illustrant la mise en oeuvre du collier de serrage suivant l'invention;
• la figure 9 est, à échelle supérieure, une vue en plan coupe, suivant la ligne IX-IX de la figure 8, de ce collier de serrage, au cours d'une première phase de sa mise en oeuvre;
• la figure 10 est une vue analogue à celle de la figure 9, pour la phase finale de la mise en oeuvre du collier de serrage suivant l'invention.

The characteristics and advantages of the invention will become apparent from the description which follows, by way of example, with reference to the appended schematic drawings in which:

• Figure 1 is, with a local cutaway, an elevational view of a clamp according to the invention; .
• Figure 2 shows, on a larger scale, the detail of Figure 1 identified by an insert II thereon;
• FIG. 3 is, on the scale of FIG. 2, a cross-sectional view of the clamp according to the invention, along the line III-III of FIG. 2:
• Figure 4 shows, on a larger scale, and with a local cutaway, the detail of Figure 1 identified by an insert IV thereon;
• Figure 5 is, on the scale of Figure 4, a partial plan view of the clamp according to the invention, according to arrow V of Figure 4;
• Figures 6 and 7 are partial perspective views of this clamp, respectively according to the arrows VI and Vll of Figure 5;
• Figure 8 is an elevational view illustrating the implementation of the clamp according to the invention;
• Figure 9 is, on a larger scale, a sectional plan view, along the line IX-IX of Figure 8, of this clamp, during a first phase of its implementation;
• Figure 10 is a view similar to that of Figure 9, for the final phase of the implementation of the clamp according to the invention.

As illustrated in these figures, the clamp according to the invention, which, in the usual way, can for example be produced by molding of any suitable synthetic material, generally comprises only one holding, on the one hand a flexible strap 10, and, on the other hand, at one of the ends thereof, a closing head 11.

On at least one of its faces, and, in practice, on only one of these, which forms the upper, or outer, face 12 thereof, in the embodiment shown, the flexible strap 10 presents transversely, between its two longitudinal edges 13, a series of notches 15.

In practice, in the embodiment shown, the notches 15, which are arranged in regular steps, are established between two massive edge edges 16, flush with them.

Anyway, these are notches with asymmetrical sides, the one, 17, of their sides which is closer to the closing head 11 being stiffer, and in practice almost vertical, than the one, 18, which is furthest from this closing head 11, FIG. 2.

It follows from the above that the upper or outer face 12 of the flexible strap 10 is reduced in practice to that of the edge edges 16.

In the embodiment shown, its lower, or inner, face 20 is planar and extends parallel to its upper face 12; as a variant, this lower, or inner, face 20 can, for example, be more or less curved, having a convexity towards the outside or inside.

In this form of assembly, according to the invention, the longitudinal edges 13 of the flexible strap 10 are at least partly transversely oblique, one with respect to the other.

In practice, in the embodiment shown, only a part 21 of these longitudinal edges 13, that closest to the underside, or interior, 20, is thus transversely oblique, the remaining part 22, that closest to the upper, or outer face, 12, being, in line with the edge borders 16, perpendicular to this upper, or outer face, 12.

In the embodiment shown in accordance with the invention by their transversely oblique parts relative to each other 21, the longitudinal edges 13 of the flexible strap 10 are transversely drawn towards each other in the direction opposite to the upper or outer face 12 of this flexible strap 10 having the notches 15.

In other words, by the parts 21 in question, the longitudinal edges 13 of the flexible strap 10 - approach transversely from one another to the notched face of the flexible strap 10 to the opposite face thereof.

Thus, and as is better visible in Figure 3, the cross section of the flexible strap 10 is at least partially trapezoidal, with a base of shorter length on the side of its face opposite to that having notches.

Preferably, and as shown in gray in FIG. 4, the transversely oblique parts with respect to each other 21, at least, of the longitudinal edges 13 of the flexible strap 10 are granulated.

Such granitation, which results in a certain surface roughness, and which can, for example, be obtained in the usual way by electro-erosion, can also, and preferably, extend on the underside, or interior, of the flexible strap 10.

In practice, in the embodiment shown, the flexible strap 10 is rooted in the closure head 11 by a connecting tongue 23, of the same width, but devoid of notches, and, at its end opposite to this closure head 11, it is extended by a gripping tab 24, which is provided with notches 25, to facilitate gripping.

In the embodiment shown, these notches 25 are established on the underside of the grip tab 24, and therefore on the face of the latter opposite the face of the flexible strap 10 having notches 15.

In a manner known per se, the closure head 11 of the clamp according to the invention has a passage 27 suitable for the engagement, by the gripping tab 24, of the flexible strap 10, for closure, in a loop, on it itself, of the latter, and it is equipped with a pawl 28 capable of cooperating in retention with the notches 15 of said flexible strap 10.

In the embodiment shown, the passage 27 of the closure head 11 extends generally perpendicular to the general mean plane at rest of the flexible strap 10, so that, as will appear below, when the latter is closed in a loop, its two ends, namely that by which it is rooted to the closure head 11, on the one hand, and that by which it is engaged in the passage 27 of this closure head 11, on the other hand, are sensibly perpendicular to each other.

Thus, in this embodiment, the clamp that is the subject of the invention is a collar of the type with a "perpendicular" head.

However, it goes without saying that the invention extends equally to clamps of the type with "tangential" head, that is to say clamps in which the passage of the closing head extends substantially parallel to the general plan at rest of the flexible strap 10, the two ends of the latter then being generally parallel to one another when it is closed in a loop on itself.

In plan, and as it is better visible, for example in FIG. 5, the closing head 11 forms a frame, of generally rectangular outline.

The two transverse edges of this frame, that is to say those of its edges which are substantially perpendicular to the flexible strap 10, are massive and extend at full height.

By cons, in the embodiment shown, the side edges of the frame thus forming the closure head 11, that is to say those of the edges of this frame which are substantially parallel to the flexible strap 10, each have, in their middle zone, a wide notch 29.

In practice, this notch 29 is open in the direction of that of the faces of the closure head 11 on which the outlet of the passage 27 which this closure head 11 opens, in the direction of engagement of the flexible strap 10.

As will be noted, it is in the central region of the closure head 11 that the flexible strap 10 is rooted therein by the connecting tongue 23.

In other words, the flexible strap 10 is rooted in the closure head 11 between the faces of this closure head 11 on which the passage 27 which the latter comprises opens.

In practice, in the embodiment shown, on the side of the flexible strap 10, that of the faces of the closure head 11 on which the entrance to the passage 27 opens which it comprises, in the direction of engagement of said flexible strap 10 has an oblique face 30, counting from said flexible strap 10.

While remaining massive, and thus robust and relatively rigid, the closing head 11 is therefore advantageously lightened, and this results in particular in a significant saving of material, without affecting the mechanical characteristics of the assembly.

Internally, the passage 27 of the closure head 11 is delimited, overall, by two transverse walls 32, 33, substantially perpendicular to the flexible strap 10, the first relatively distant from this flexible strap 10, the second relatively close to the latter, and by two similar side walls 34.

In the embodiment shown, the notches 15 of the flexible strap 10 being arranged on the upper or outer face 12 of the latter, the pawl 28 extends from the transverse wall 32 of the passage 27 of the closure head 11, that is to say from that of the transverse walls of the passage 27 which, as specified above, is the furthest from the flexible strap 10.

The pawl 28 comes in one piece from the wall 32, by a zone of reduced thickness 36 forming a hinge.

Given the material of the clamp according to the invention, it is thus elastically articulated to the closure head 11 which it equips, and, at rest, it defines with the transverse wall 33 opposite the passage 27 thereof. ci a neck 37 of width L1 less than the thickness L2 of the flexible strap 10, FIGS. 5 and 2.

In the embodiment shown, the pawl 28 extends entirely inside the passage 27 of the closure head 11, substantially parallel to its transverse walls 32, 33.

In other words, in this embodiment, the pawl 28 does not protrude from the closure head 11.

It should be noted, however, that, in a manner known per se, its free end extends to the right of the notches 29 of the closing head 11, which, in particular, facilitates molding.

The tilting, in one direction, of the pawl 28 is delimited by the corresponding transverse wall 32 of the passage 27 of the closing head 11, this pawl 28 being able to come directly to bear against this transverse wall 32, from which it is normally only separated by a blind notch 40.

Its tilting in the other direction is also delimited by the transverse wall 32 of the passage 27 of the closure head 11, a heel 41 which it has for this purpose at its base which can come to bear against the corresponding part of this transverse wall 32.

At its free end, the pawl 28 comprises, in the embodiment shown, two teeth 43, by which it is adapted to cooperate in retention with the notches 15 of the flexible strap 10.

In the embodiment of the invention, and similarly to the longitudinal edges 13 of the flexible strap 10, the two lateral walls 34 of the passage 27 of the closure head 11 are, on at least part of their dimensions, transversely oblique to each other.

In practice, in the embodiment shown, each of these side walls 34 has a part 44, substantially parallel to the flexible strap 10 and a part 45 oblique thereon.

In the embodiment of the clamp forming the object of the invention, the transversely oblique parts with respect to each other 45 which thus comprise the side walls 34 of the passage 27 of the closure head 11 come closer transversely from each other in the direction opposite to the pawl 28.

They extend at least in part to the right of the free end thereof.

In practice, in the embodiment shown, and as is better visible in FIG. 6, they extend over the entire height of the passage 27 of the closure head 11.

Preferably, and as shown in gray in this FIG. 6, they are granitized, according to a process and for the reasons specified above.

In practice, and in a manner known per se, the passage 27 of the closure head 11 has, internally, two coplanar shoulders 47 each disposed respectively on either side of the pawl 28, FIGS. 4, 5 and 7.

In the embodiment of the invention, and as will appear below, these shoulders 47 are sufficiently close to the free end of the pawl 28 to be suitable for supporting the flexible strap 10 during the engagement of the latter in said passage 27.

In practice, these shoulders 47 are in an offset relative to the corresponding transverse wall 32 of this passage 27, in the direction of the opposite transverse wall 33 thereof.

However, for molding conveniences, and as is better visible in FIG. 7, they have a greater width at the right of the heel 41 of the pawl 28 than at the right of the free end thereof.

For its implementation, and being, for example, as shown schematically by hatching in Figure 8, to ensure the connection between them of a cable harness 50, the clamp according to the invention is passed around this bundle of cables 50, and, by the gripping tab 24, its flexible strap 10 is engaged in the passage 7 of its closure head 11.

Under the effects of the traction exerted on it, this flexible strap 10 comes, by its edge edges 16, to bear against the shoulders 47 provided, for this purpose, in the passage 27 of the closure head 11, FIG. 9.

Jointly, during this traction, the pawl 28 elastically escapes, notch by notch, from the notches 15 of the flexible strap 10, its corresponding tilting towards the rear being limited by the transverse wall 32 of the passage 27 of the closure head 11.

When, in FIG. 10, the traction thus exerted on the flexible strap 10 of the clamp according to the invention for implementing it is released, the pawl 28 resiliently pushes this flexible strap 10 towards the transverse face 33 of the passage 27 of the closing head 11 which is opposite to it.

The transversely oblique parts 21 of the longitudinal edges 13 of this flexible strap 10 then come into contact with the corresponding transversely oblique parts 45 of the side walls 34 of the passage 27.

Therefore, under the bias of the pawl 28, it develops, by a wedge effect, a transverse pinching of the flexible strap 10 between the side walls 34 of the passage 27 of the closure head 11, so as to strengthen, all the more sure that it intervenes between granite surfaces, the closure itself thus ensured of the flexible strap 10.

According to the invention and as it is better visible in FIG. 10, it has been provided that a D-day then remains between the lower or inner face 20 of the flexible strap 10, on the one hand, and the corresponding transverse wall 33 of the passage 27 of the closure head 11, on the other hand.

But, in particular if, under the request of the pawl 28, this lashing strap 10 transversely takes an arrow, such a day can, at least locally, disappear.

The present invention is moreover not limited to the embodiment shown, but encompasses any variant.

For example, the expression "generally oblique" applied to all or part of the longitudinal edges of the flexible strap does not necessarily imply that said part of said edges is flat, as more particularly envisaged in the embodiment shown; on the contrary, it could for example be at least partly curved.

In addition, instead of being trapezoidal, the part concerned with the cross section of the flexible strap could for example be triangular.

In addition, as mentioned above, the field of application of the invention is not limited to clamps whose closing head is of the "perpendicular" type, but on the contrary extends equally to clamps whose closing head is of the "tangential" type.

In addition, the field of application of the invention is also not limited to clamps with external notches, that is to say clamps whose notches 15 of the flexible strap 10 are directed towards 1, external during their implementation, as described above, but extends on the contrary as well to the clamps with internal notching, that is to say the clamps whose notches are then directed inward during such an implementation.

Finally, in all cases, notches can be provided on either of the faces of the flexible strap 10, the notches thus provided on the underside, or interior, of the latter being able to cooperate with, for example, a tooth established opposite the pawl 28, in the passage 27 of the closing head 11.

Claims (10)

1. A clamping clip of the kind comprising, in one piece, on the one hand a flexible strap (10) which is provided transversely with a series of teeth (15) on one at least (12) of its faces, between its two longitudinal edges (13), and on the other hand a closure head (11) having a passage (27) for engagement of the flexible strap (10) in order for the flexible strap to be closed on to itself on a loop configuration, the closure head being provided with a pawl (28) capable of coming into retaining co-operation with the teeth (15) of said flexible strap (10), said longitudinal edges (13) of said flexible strap (10) being at least in part transversely inclined with respect to each other, coming transversely closer together in the opposite direction to the face (12) of said flexible strap (10) having the teeth (15) co-operable with said pawl (28), and the passage (27) of the closure head (11) being provided, in corresponding relationship to the parts which are thus transversely inclined with respect to each other of the longitudinal edges (13) of the flexible strap (10), with two side walls (34) which, over a part at least of their dimensions, are similarly transversely inclined with respect to each other, characterised in that the closure head (11) is closed back on to itself in such a way that, by a wedge effect, under the force applied by the pawl (28), the flexible strap (10) is transversely pinched between the corresponding side walls (34) of said passage (27) of the closure head (11), with a clearance (J) being left between the inside face (20) of the flexible strap (10) on the one hand and the corresponding side wall (33) of the passage (27) of the closure head on the other hand.

2. A clamping clip according to claim 1 characterised in that, by means of their parts which are transversely inclined one with respect to the other, the side walls (34) of the passage (27) of the closure head (11) come transversely closer together in the opposite direction to the pawl (28).

3. A clamping clip according to claim 1 or claim 2 characterised in that the parts which are transversely inclined with respect to each other of the side walls (34) of the passage (27) of the closure head (11) extend at least in part in line with the free end of the pawl (28).

4. A clamping clip according to any one of claims 1 to 3 characterised in that the parts which are transversely inclined with respect to each other of the longitudinal edges (13) of the flexible strap (10) at least are pebbled.

5. A clamping clip according to any one of claims 1 to 4 characterised in that the parts which are transversely inclined with respect to each other of the side walls (34) of the passage (27) in the closure head (11) at least are pebbled.

6. A clamping clip according to any one of claims 1 to 5 wherein the passage (27) in the closure head (11) has two coplanar shoulders (47) which are each disposed on respective sides of the pawl (28) characterised in that said shoulders (47) are sufficiently close to the free end of said pawl (28) to be capable of supporting the flexible strap (10) when it is engaged in said passage (27).

7. A clamping clip according to claim 6 characterised in that said shoulders (47) are set back with respect to the wall (32) of the passage (27) in the closure head (11) from which the pawl (28) extends in the direction of the opposite wall of said passage (27).

8. A clamping clip according to either one of claims 6 and 7 wherein the pawl (28) comprises a heel portion (41) characterised in that the width of said shoulders (47) is greater in line with said heel portion (41) than in line with the free end of the pawl (28).

9. A clamping clip according to any one of claims 1 to 8 characterised in that the flexible strap (10) is connected to the closure head (11) in the middle region thereof between the faces of said closure head (11) at which the passage (27) in the closure head opens.

10. A clamping clip according to claim 9 characterised in that, at the side towards the flexible strap (10), that one of the faces of the closure head (11) at which the entrance of the passage (27) in the closure head opens has an inclined surface portion (30).

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