Band clamp with a metal band with an ear-shaped tensioning device with a concave profile

Abstract

The invention relates to a band clamp (10) with a metal band and an ear-shaped tensioning device (12), wherein the ear-shaped tensioning device (12) has two lateral leg sections (12a, 12b) and a connecting section (12c) connecting the lateral leg sections (12a, 12b), wherein the connecting section (12c) comprises a projection (14) which projects radially inwardly, wherein the projection (14) is configured such that it prevents buckling of material arranged under the ear-shaped tensioning device (12) when the ear-shaped tensioning device (12) is tensioned by bringing the leg sections (12a, 12b) closer together. It is proposed that in a non-tightened configuration of the band clamp (10), the radially inner side (14a) of the projection (14) has a concave profile when viewed in the axial direction of the band clamp (10).

Description

The invention relates to a band clamp according to the preamble of claim 1.Documents DE2920983A1 and DE2255110A1 disclose strap clamps comprising a metal strap with an ear-shaped tensioner, the ear-shaped tensioner comprising two lateral leg portions and a connecting portion connecting the lateral leg portions, the connecting portion comprising a protrusion projecting radially inwardly, the protrusion being configured to prevent buckling of the material arranged under the ear-shaped tensioner when the ear-shaped tensioner is tensioned by bringing its leg portions closer together.Prior art buckling prevention protrusions generally have convex or flat profiles for ease of manufacture in the unfastened state. This flat or convex shape leads to a certain distance to the radially inner side of the protrusion at least in portions outside the center of the protrusion in the circumferential direction. This means that the bulging of the material cannot be completely prevented.The problem is solved by a device having the features of claim 1. Advantageous embodiments of the invention are defined in the dependent claims.The invention relates to a band clamp comprising a metal band with an ear-shaped tensioner, the ear-shaped tensioner comprising two lateral leg portions and a connecting portion connecting the lateral leg portions, the connecting portion comprising a protrusion projecting radially inwardly, the protrusion being configured to prevent buckling of the material disposed under the ear-shaped tensioner when the ear-shaped tensioner is tightened by approaching its leg portions.The lateral leg portions project generally radially or approximately radially outward from a main portion of the band clamp. The skilled person will understand that the above mentioned protrusion protrudes radially inward in the sheet material of the band and, when viewed from the radially outer side, corresponds to a depression or a dimple. In the context of this document, and unless otherwise stated, the terms "radial", "axial", or "circumferential" refer to the circular shape of the band clamp as a whole in a pre-assembled and unfastened or in a tightened configuration.The invention is applicable to various types of ribbon clamps. Depending on the type of band clamp, the material arranged under the ear-shaped clamping device can be a hose or a bellows, an insert of the band clamp or an inner band section of the band clamp depending on the circumstances.It is proposed that the radially inner side of the protrusion has a concave profile when viewed in the axial direction of the band clamp. The concave profile allows the profile of the protrusion to follow the convex profile of the material arranged under the ear-shaped clamping device and improve the anti-kink effect.According to a preferred embodiment of the invention, the inventors propose that in the unfastened configuration of the band clamp, the radially inner side of the protrusion is arranged on a plane with the radially inner side of the metal band, which is adjacent to the leg portions of the ear-shaped tightening device. Accordingly, the radially inner side of the protrusion can be brought into contact with the material disposed under the ear-shaped jig at the start of tightening, which further improves prevention of buckling.It is also proposed that the radius of curvature of the concave profile is equal to the radius of curvature of a main portion of the metal strip. As a result, the profile of the protrusion follows the convex profile of the material arranged under the ear-shaped clamping device.In a preferred embodiment of the invention, a lower portion of the protrusion is provided with at least one embossed reinforcing structure. The embossed structure reinforces the material by work hardening and by increasing the rigidity, so that the buckling preventing contact is maintained during the tension operation for a long period of time and the protrusion is not easily deformed.Preferably, the at least one reinforcing structure comprises a step extending in the circumferential direction. The circumferential direction is the direction in which stiffening is most needed, and the step can further improve the orientation of the clamp during tightening.It is further proposed that the band clamp further comprises an inner band portion arranged below the ear-like tightening device. The inner band portion includes at least one rib extending circumferentially, the rib configured to engage the radially inner side of the protrusion and align the inner band portion with the protrusion. This improves the alignment of the inner band portion and the outer band portion with the jig. Since improper alignment may be a cause of buckling, the improved alignment further reduces the risk of buckling.Preferably, the rib of the inner band portion is configured to engage the step in the lower portion of the protrusion. The step-rib engagement forms guide rails which guide the relative movement of the inner strap portion upon tightening. Preferably, the above-described ribs and steps are provided on both axial sides of the protrusion.Further features and advantages will become apparent from the following description of the embodiments and figures. The entire specification, claims and figures disclose features of the invention in specific embodiments and combinations. Those skilled in the art will also consider the features individually and combine them into further combinations or sub-combinations to adapt the invention as defined in the claims to its needs or specific areas of application.The figures illustrate the following: FIG. 1 shows a band clamp according to a first embodiment of the invention; FIG. 2 is a detail of an ear-shaped tensioner of the band clamp of FIG. 1 ; FIG. 3 is a radial section of the band clamp of FIG. 1 with an inner band portion; FIG. 4 is a radial section of a protrusion of the band clamp of the ear-like tensioner of the band clamp of FIG. 1 ; FIG. 5 is a view of the ear-shaped jig from a radially inner side; FIG. 6 is a view of the ear-shaped tensioner from a radially outer side; and FIG. 7 is a perspective view of the ear-shaped jig from a radially outer side.FIG. 1 shows a band clamp according to a first embodiment of the invention in an unfastened configuration. The invention relates to a strap clamp 10 comprising a metal strap with an ear-shaped tensioner 12, the ear-shaped tensioner 12 comprising two lateral leg portions 12a, 12b and a connecting portion 12c connecting the lateral leg portions 12a, 12b, the connecting portion 12c comprising a protrusion 14 projecting radially inward, the protrusion 14 being configured to prevent buckling of material disposed under the ear-shaped tensioner 12 when the ear-shaped tensioner 12 is tensioned by approaching its leg portions 12a, 12b together.The strap clamp 10 is comprised of an embossed metal strap that is closed to form a loop. The band clamp 10 has an outer band portion 10a comprising the ear-shaped tensioner 12, the outer band portion 10a partially overlapping an inner band portion 10b provided with a tongue 10c at its end. Tongue 10c engages tongue channel 10d and the band is closed by the engagement of hooks 10e on inner band portion 10b with apertures 10f on outer band portion 10a as a mechanical lock on a side of ear tensioner 12 opposite the circumferential side of tongue 10c and tongue channel 10d.In the embodiment of Fig. 1, the material disposed under the ear-shaped tensioner 12 is the inner band portion 10b. However, the invention is not limited to clamps with mechanical locking and an inner strap portion 10b and is applicable to clamps without an inner strap portion 10b which is arranged under the ear-shaped clamping device 12, i.e. in which a hose or other element to be clamped is arranged under the ear-shaped clamping device 12.When tightening the band clamp 10, the ear-shaped jig 12 is compressed in the circumferential direction by a crimping tool acting on the radially inner ends of the leg portions 12 a, 12 band by pressing the connecting portion 12 cradially inward to obtain a flattened loop (not illustrated). In the course of this tightening operation, the inner band portion 10b moves with respect to the center of the ear-shaped tensioner 12, and the tongue 10c slides into the tongue channel 10d.According to the invention, in an unfastened configuration of the band clamp 10, as shown in FIG. 1, the radially inner side 14 aof the protrusion 14 has a concave profile when viewed in the axial direction of the band clamp 10. In the embodiment of Fig. 1, the radially inner side 14a of the protrusion 14 is disposed on a plane with the radially inner side of the outer band portion 10a of the metal band adjacent the leg portions 12a, 12b of the ear-shaped tensioner 12. Accordingly, not only the center of the protrusion 14, but also an entire portion covering a part of the radially inner side 14 aof the protrusion 14 comes into direct contact with the inner band portion 10 band prevents the inner band portion 10 bfrom flexing upon tightening the band clamp 10.FIG. 2 is a detail of an ear-like clamp 12 of the band clamp 10 of FIG. 1, FIG. 3 is a radial section of the band clamp 10 of FIG. 1 with an inner band portion 10 balong the line III-III in FIG. 1, and FIG. 4 is a radial section of a protrusion 14 of the band clamp 10 of the ear-like clamp 12 of the band clamp 10 of FIG. 1 along the line III-III in FIG. 1.As illustrated in FIG. 2, the connecting portion 12 cis substantially flat in side view, and the protrusion 14 protrudes radially inward. In the axial profile of Fig. 2, the side surfaces 14b, 14c of the protrusion 14 are tapered conically so that the width of the protrusion 14, which is 70-90% of that of the circumferential length of the connecting portion 12c on the radially outermost plane, is reduced in the radially inward direction, where it is 40-70% of the circumferential length of the connecting portion 12c. The radially innermost side 14 aof the protrusion 14 connects the side surfaces and has the concave profile described above. In order to ensure good alignment, the radially inner side 14a has a radius of curvature equal to the radius of curvature of a main portion of the metal strip which is substantially, i.e. apart from permissible tolerances, adapted to the radius of curvature of the outer surface of the material or object to be clamped or, if present, to the radius of curvature of the inner strip portion 10b, i.e. to the radius of curvature of the outer surface of the object against which the radially inner side 14a of the protrusion 14 abuts prior to tightening the strip clamp 10 and / or in an initial phase of tightening.As illustrated in FIG. 3, a lower portion of the protrusion 14 is provided with at least one embossed reinforcing structure including two lateral steps 14 d, 14 ethat each extend in a circumferential direction of the band clamp 10, i.e., in a longitudinal direction of the metal band and the protrusion 14, over the entire length of the protrusion 14. The inner band portion 10b includes two ribs 18a, 18b also extending circumferentially, the ribs 18a, 18b being configured to engage the steps 14d, 14e on the radially inner side 14a of the protrusion 14 and align the inner band portion 10b with the protrusion 14. The ribs 18a, 18b and steps 14d, 14e form a type of rail which guide the relative movement of the radially inner band portion 10b and move the tongue 10c into the tongue channel 10d when the band clamp 10 is tightened.As shown in Figures 4 to 7, the projection 14 on the radially inner side 14a of the strip corresponds to a recess on the radially outer side of the strip. The recess 16 is surrounded by a substantially rectangular frame-shaped section of the metal strip. The recess 16 is formed by deep drawing and embossing the steps 14d, 14e and the reinforcing structures that cause work hardening of the protrusion 14. Thereby, the bending rigidity of the connecting portion 12 cof the ear-like jig 12 is increased, so that the connecting portion 12 cremaines its substantially flat shape in the course of the clamping operation.List of Reference Numbers10 Band clamp 10 a Äußerer band portion 10 b Innerer band portion 10 c Zunge 10 d Channel 10 e Haken 10 f Öffnungen 10 d Zungen channel 12 Ear-shaped jig 12 a, 12 b Schenkel portions 12 cConnecting portion 14 Protrusion 14 aRadially inner side 14 b Seitenfläche surface 14 c Surface 14 d, 14 e Stufen 16 Recess 18 a, 18 bReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 2920983A1

[0002] DE 2255110A1

[0002]

Claims

A band clamp (10) comprising a metal band having an ear-shaped tensioner (12), the ear-shaped tensioner (12) having two lateral leg portions (12a, 12b) and a connecting portion (12c) connecting the lateral leg portions (12a, 12b), the connecting portion (12c) comprising a protrusion (14) protruding radially inward, the protrusion (14) being configured to prevent buckling of material disposed below the ear-shaped tensioner (12) when the ear-shaped tensioner (12) is tensioned by approaching its leg portions (12a, 12b) together, characterized in that in an unfastened configuration of the band clamp (10), the radially inner side (14a) of the protrusion (14) has a concave profile as viewed in an axial direction of the band clamp (10).The band clamp (10) of claim 1, characterized in that in the unfastened configuration of the band clamp (10), the radially inner side (14a) of the protrusion (14) is disposed in a plane with the radially inner side (14a) of the metal band adjacent the leg portions (12a, 12b) of the ear shaped tensioner (12).The band clamp (10) according to any of the preceding claims, characterized in that a radius of curvature of the concave profile is equal to a radius of curvature of a main portion of the metal band.A band clamp (10) according to any preceding claim, characterized in that a lower portion of the protrusion (14) is provided with at least one embossed reinforcing structure.The band clamp (10) of claim 4, characterized in that the at least one reinforcing structure comprises a step (14d, 14e) extending in a circumferential direction of the band clamp.The band clamp (10) according to any of the preceding claims, characterized in that it further comprises an inner band portion (10b) arranged below the ear-like tensioner (12), the inner band portion (10b) comprising at least one rib (18a, 18b) extending in a circumferential direction, the rib (18a, 18b) being configured to engage the radially inner side (14a) of the protrusion (14) and align the inner band portion (10b) with the protrusion (14).A band clamp (10) according to claim 4 and 6, characterized in that the rib (18a, 18b) of the inner band portion (10b) is configured to engage the step in the lower portion of the protrusion (14).

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