Band clamp including a metal band with an ear-shaped tightening device having a concave profile

Abstract

The invention relates to Band clamp (10) including a metal band with an ear-shaped tightening device (12), wherein the ear-shaped tightening device (12) includes two lateral leg portions (12a, 12b) and a connecting portion (12c) connecting the lateral leg portions (12a, 12b), wherein the connecting portion (12c) includes a protrusion (14) protruding radially inward, wherein the protrusion (14) is configured to prevent buckling of material arranged underneath the ear-shaped tightening device (12) when the ear-shaped tightening device (12) is being tightened by approaching the leg portions (12a, 12b) thereof. It is proposed that in a non-tightened configuration of the band clamp (10), a radially inner side (14a) of the protrusion (14) has a concave profile when viewed in an axial direction of the band clamp (10).

Description

[0001] Band clamp including a metal band with an ear- shaped tightening device having a concave profile

[0002] The invention relates to a band clamp according to the preamble of claim 1 .

[0003] The documents DE2920983A1 , and DE2255110A1 disclose band clamps including a metal band with an ear-shaped tightening device , wherein the ear-shaped tightening device includes two lateral leg portions and a connecting portion connecting the lateral leg portions , wherein the connecting portion includes a protrusion protruding radially inward, wherein the protrusion is configured to prevent buckling of material arranged underneath the ear- shaped tightening device when the ear-shaped tightening device is being tightened by approaching the leg portions thereof .

[0004] The document GB 2 160 577 A discloses a band clamp according to the preamble of the claim 1 .

[0005] Buckling-preventing protrusions according to the prior art gen- erally have convex or flat profiles in the non-tightened config- uration for reasons of ease of manufacturing . This flat or con- vex shape entails , at least in portions outside of the circum- ferential centre of the protrusion, a certain distance between the radially inner side of the protrusion exists . This means that the bucking of the material cannot be completely prevented .

[0006] The problem is solved by a device having the features of claim 1 . Advantageous embodiments of the invention are defined in the dependent claims .

[0007] The invention relates to a band clamp including a metal band with an ear-shaped tightening device , wherein the ear-shaped tightening device includes two lateral leg portions and a con- necting portion connecting the lateral leg portions , wherein the connecting portion includes a protrusion protruding radially in- ward, wherein the protrusion is configured to prevent buckling of material arranged underneath the ear-shaped tightening device when the ear-shaped tightening device is being tightened by ap- proaching the leg portions thereof .

[0008] The lateral leg portions generally protrude radially or roughly radially outward form a main portion of the band clamp . The skilled person will understand that , in the sheet metal material of the band, protrusion mentioned above protrudes radially in- ward and corresponds to a recess or dimple when viewed from the radial outside . In the context of this document and unless indi- cated otherwise , the expressions "radial" , "axial" or "circum- ferential" refer to the circular shape of the band clamp as a whole in a pre-assembled and non-tightened or in a or tightened conf iguration .

[0009] The invention is applicable to various kinds of band clamps . De- pending on the type of band clamp, the material arranged under- neath the ear-shaped tightening device may be a hose or bellows , an inlay of the band clamp or an inner band portion of the band clamp, depending on the circumstances .

[0010] It is proposed that the radially inner side of the protrusion has a concave profile when viewed in an axial direction of the band clamp . By means of the concave profile , the profile of the protrusion can follow the convex profile of the material ar- ranged underneath the ear-shaped tightening device and enhance the buckling prevention .

[0011] According to a preferred embodiment of the invention, the inven- tors propose that in the non-tightened configuration of the band clamp, the radially inner side of the protrusion is arranged at one level with the radially inner side of the metal band ad- j acent to the leg portions of the ear-shaped tightening device . Accordingly, the radially inner side of the protrusion can be arranged in contact with the material arranged underneath the ear-shaped tightening device when the tightening is initiated, which further enhances the buckling prevention . It is further proposed that a radius of curvature of the concave profile is equal to the radius of curvature of a main portion of the metal band . As a result, the profile of the protrusion fol- lows the convex profile of the material arranged underneath the ear-shaped tightening device .

[0012] In a preferred embodiment of the invention, a bottom portion of the protrusion is provided with at least one embossed reinforc- ing structure . The embossed structure strengthens the material by strain hardening and by increasing the stiffness such that the buckling-preventing contact is maintained for a long time in the course of the tightening process and the protrusion is not easily deformed .

[0013] Preferably, the at least one reinforcing structure includes a step extending in a circumferential direction . The circumferen- tial direction is the direction where stiffening is required most and the step may further enhance alignment of the clamp in the course of the tightening .

[0014] It is further proposed that the band clamp further includes an inner band portion arranged underneath the ear-like tightening device . The inner band portion includes at least one rib extend- ing in a circumferential direction, wherein the rib is config- ured to engage with the radially inner side of the protrusion and to align the inner band portion with the protrusion . This improves alignment of the inner band portion and of the outer band portion having the tightening device . Considering that im- precise alignment may be a reason for buckling, the improved alignment reduces the risk of bucking even further .

[0015] Preferably, the rib of the inner band portion is configured to engage with the step in the bottom portion of the protrusion . The engaging step and rib provide guiding rails for guiding the relative movement of the inner band portion in the tightening proces s . Preferably, ribs and steps as described in above are provided on both axial sides of the protrusion . Further features and advantages will be apparent from the fol- lowing description of the embodiments and figures . The entire description, claims and figures disclose features of the inven- tion in specific embodiments and combinations . The person 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 his needs or to specific fields of application .

[0016] The figures illustrate the following :

[0017] Fig . 1 a band clamp according to a first embodiment the in- vention ;

[0018] Fig . 2 is a detail of an ear-like tightening device of the band clamp of Fig . 1 ;

[0019] Fig . 3 is a radial section of the band clamp of Fig . 1 with an inner band portion ;

[0020] Fig . 4 is a radial section of a protrusion the band clamp of the ear-like tightening device of the band clamp of Fig . 1 ;

[0021] Fig . 5 is a view of of the ear-like tightening device from a radially inner side ;

[0022] Fig . 6 is a view of of the ear-like tightening device from a radially outer side ; and

[0023] Fig . 7 is a perspective view of of the ear-like tightening device from a radially outer side .

[0024] Fig . 1 a band clamp according to a first embodiment the inven- tion in a non-tightened configuration . The invention relates to a band clamp 10 including a metal band with an ear-shaped tight- ening device 12 , wherein the ear-shaped tightening device 12 in- cludes two lateral leg portions 12a, 12b and a connecting por- tion 12c connecting the lateral leg portions 12a, 12b , wherein the connecting portion 12c includes a protrusion 14 protruding radially inward, wherein the protrusion 14 is configured to pre- vent buckling of material arranged underneath the ear-shaped tightening device 12 when the ear-shaped tightening device 12 is being tightened by approaching the leg portions 12a , 12b there- of . The band clamp 10 is made of an embossed metal band closed to form a loop . The band clamp 10 has an outer band portion 10a in- cluding the ear-shaped tightening device 12 , wherein the outer band portion 10a partially overlaps an inner band portion 10b provided with a tongue 10c on its end . The tongue 10c engages with a tongue channel l Od and the band is closed by the engage- ment of hooks l Oe on the inner band portion 10b with openings l O f on the outer band portion 10a as a mechanical interlock on a side of the ear-shaped tightening device 12 opposite to the side of the tongue 10c and the tongue channel l Od in the circumferen- tial direction .

[0025] In the embodiment of Fig . 1 , the material arranged underneath the ear-shaped tightening device 12 is the inner band portion 10b . However, the invention is not limited to clamps with me- chanical interlock and an inner band portion 10b and is applica- ble to clamps without inner band portion 10b arranged underneath the ear-shaped tightening device 12 , i . e . where a hose or other item to be clamped is arranged underneath the ear-shaped tight- ening device 12 .

[0026] When the band clamp 10 is being tightened, the ear-shaped tight- ening device 12 is compressed in the circumferential direction by a crimping tool acting on the radially inner ends of the leg portions 12a , 12b and by pressing the connecting portion 12c ra- dially inward to obtain a flattened loop (not illustrated) . In the course of this tightening operation, the inner band portion 10b moves in relation to the centre of the ear-shaped tightening device 12 and tongue 10c slides into the tongue channel l Od .

[0027] According to the invention, in a non-tightened configuration of the band clamp 10 as illustrated in Fig . 1 , the radially inner side 14a of the protrusion 14 has a concave profile when viewed in an axial direction of the band clamp 10 . In the embodiment of Fig . 1 , the radially inner side 14a of the protrusion 14 is ar- ranged at one level with the radially inner side of the outer band portion 10a of the metal band adj acent to the leg portions 12a, 12b of the ear-shaped tightening device 12 . Accordingly, a direct contact with not only the centre of the protrusion 14 but rather with an entire section covering a part of the radially inner side 14a of the protrusion 14 will come in direct contact with the inner band portion 10b and prevents the inner band por- tion 10b form buckling up when the band clamp 10 is being tight- ened .

[0028] Fig . 2 is a detail of an ear-like tightening device 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 10b along the line I I I -I I I in Fig . 1 and Fig . 4 is a radial section of a protrusion 14 the band clamp 10 of the ear-like tightening device 12 of the band clamp 10 of Fig . 1 along the line I I I-I I I in Fig . 1 .

[0029] As illustrated in Fig . 2 , the connecting portion 12c is substan- tially flat in the side view and the protrusion 14 protrudes ra- dially inward . In the axial profile of Fig . 2 , side faces 14b , 14 c of the protrusion 14 are tapered conically such that the width of the protrusion 14 , which amounts to 70 - 90 % of the circumferential length of the connecting portion 12c at the ra- dially outermost level , is reduced in the direction radially in- ward, where it amounts to 40 - 70% of the circumferential length of the connecting portion 12c . The radially innermost side 14a of the protrusion 14 connects the side faces and has the concave profile as described above . In order to ensure a good alignment of the radially inner side 14a has a radius of curvature equal to the radius of curvature of a main portion of the metal band, which essentially, i . e . besides of allowable tolerances , is adapted to the radius of curvature of the outer surface of the material or item being clamped or, if existent , to the radius of curvature of the inner band portion 10b, i . e . to the radius of curvature of the outer surface of the item on which the radially inner side 14a of the protrusion 14 abuts prior to tightening of the band clamp 10 and / or in an initial phase of the tightening .

[0030] As illustrated in Fig . 3 , a bottom portion of the protrusion 14 is provided with at least one embossed reinforcing structure in- eluding two lateral steps 14d, 14e each extending in a circum- ferential direction of the band clamp 10 , i . e . in a longitudinal direction of the metal band and of the protrusion 14 over the entire length of the protrusion 14 . The inner band portion 10b includes at two ribs 18a, 18b extending in a circumferential di- rection likewise , wherein the ribs 18a, 18b are configured to engage with the steps 14d, 14e on the radially inner side 14a of the protrusion 14 and to align the inner band portion 10b with the protrusion 14 . The ribs 18a, 18b and the steps 14d, 14e form a kind of rails for guiding the relative movement of the radial- ly inner band portion 10b moving the tongue 10c into the tongue channel l Od when the band clamp 10 is being tightened .

[0031] As illustrated in Figs . 4 - 7 , the protrusion 14 on the radially inner side 14a of the band corresponds to a recess on 16 the ra- dially outer side of the metal band . The recess 16 is surrounded by a substantially rectangular, frame-shaped portion of the met- al band . The recess 16 is formed by deep drawing and embossing the steps 14d, 14e , and the reinforcing structures provide strain hardening of the protrusion 14 . This enhances the bending stif fness of the connecting portion 12c of the ear-like tighten- ing device 12 such that the connecting portion 12c retains its es sentially flat shape in the course of the tightening proces s .

[0032] List of reference numbers

[0033] 10 band clamp

[0034] 10a outer band portion

[0035] 10b inner band portion

[0036] 10c tongue l Od tongue channel l Oe hooks l O f openings l Od tongue channel

[0037] 12 ear-shaped tightening device 12a, 12b leg portions

[0038] 12 c connecting portion

[0039] 14 protrusion

[0040] 14a radially inner side

[0041] 14b side face

[0042] 14 c side face

[0043] 14d, 14e steps

[0044] 16 recess

[0045] 18a, 18b ribs

Claims

Claims1. Band clamp (10) including a metal band with an ear-shaped tightening device (12) , wherein the ear-shaped tightening device (12) includes two lateral leg portions (12a, 12b) and a connecting portion (12c) connecting the lateral leg portions (12a, 12b) , wherein the connecting portion (12c) includes a protrusion (14) protruding radially inward, wherein the protrusion (14) is configured to prevent buck- ling of material arranged underneath the ear-shaped tight- ening device (12) when the ear-shaped tightening device (12) is being tightened by approaching the leg portions (12a, 12b) thereof, wherein, in a non-tightened configuration of the band clamp (10) , a radially inner side (14a) of the protrusion (14) has a con- cave profile when viewed in an axial direction of the band clamp (10) , characterized in that in the non-tightened configuration of the band clamp (10) , the radially inner side (14a) of the protrusion (14) is ar- ranged at one level with a radially inner side of the metal band adjacent to the leg portions (12a, 12b) of the ear- shaped tightening device (12) .

2. Band clamp (10) according to one of the preceding claims, characterized in that a radius of curvature of the concave profile is equal to the a radius of curvature of a main portion of the metal band .

3. Band clamp (10) according to one of the preceding claims, characterized in that a bottom portion of the protrusion (14) is provided with at least one embossed reinforcing structure.

4. Band clamp (10) according to claim 3, characterized in thatthe at least one reinforcing structure includes a step (14d, 14e) extending in a circumferential direction of the band clamp (10) .

5. Band clamp (10) according to one of the preceding claims, characterized by further including an inner band portion (10b) arranged underneath the ear-like tightening device (12) , wherein the inner band portion (10b) includes at least one rib (18a, 18b) extending in a circumferential di- rection, wherein the rib (18a, 18b) is configured to engage with the radially inner side (14a) of the protrusion (14) and to align the inner band portion (10b) with the protru- sion (14) .

6. Band clamp (10) according to claim 3 and 5, characterized in that the rib (18a, 18b) of the inner band portion (10b) is con- figured to engage with the step (14d, 14e) in the bottom portion of the protrusion (14) .

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