Tension clamp with reinforced locking hooks

Abstract

The invention relates to a clamping clamp (10) made of a clamping band (1) with a first and a second circumferential end section (2, 3) which overlap when the clamping clamp (10) is closed. The clamping clamp (10) comprises a connecting hook (20) projecting radially outwards from the first end section (2), a first clamping hook (30) projecting radially outwards from the first end section (2), and a second clamping hook (40) projecting radially outwards from the second end section (3) with an opening (42) for receiving an edge section (21) of the connecting hook (20) when the clamping clamp (10) is closed.Of the connecting hook (20) and the first and second tension hooks (30, 40), at least one has a cut-out window (22, 43) in which a two-dimensional area of ​​material is removed from the clamp band (1), wherein the window cut-out (22, 43) preferably has rounded, arc-shaped sections (24) in areas laterally adjacent to the edge section (21) of the connecting hook (20) and / or a tooth-like projection (31, 41) of the first or second tension hook (30, 40) which prevent cracking on these sections when the tension clamp (10) is subjected to high radial tensile forces.

Description

[0001] The present invention relates to a clamping clamp made from a flat metal band or strip formed into a ring for fastening around an object with a substantially circular cross-section, such as a hose, pipe, or sleeve. In particular, the present invention relates to so-called "low-profile clamps," i.e., clamping clamps with only slightly radially outward-projecting parts, resulting in a relatively small radial height in the overall clamp profile. Furthermore, the present invention relates in particular to so-called "stepless clamps," i.e., clamping clamps that, in the closed state, have virtually no irregularities or steps on their inner surface.

[0002] US 2009 / 0313792 A1 discloses a conventional clamp with a connecting hook (fastening stud) projecting radially outwards near the first end of the band and a clamping hook (fastening ear) projecting radially outwards near the second end of the band, which is provided with an opening into which a free end edge section of the connecting hook can be inserted for the purpose of fastening and tensioning the clamp, while the fastening ear fits over a foot section of the connecting hook.

[0003] WO 2018 / 082819 A1 gives another example of such a conventional clamp with a locking hook in the form of a connecting hook and two clamping hooks for tightening the clamp around the object to be fastened with a clamping tool such as pliers.

[0004] A disadvantage of these conventional clamps lies in the inadequate load-bearing capacity of the locking hooks. When the closed clamp is subjected to high radial tensile forces, the edge section of the connecting and / or tensioning hooks tends to deform and / or cracks develop in the strap material along the sides of the edge section. Furthermore, cracks can already occur in conventional clamps during the manufacturing process, such as when the hooks are cut and stamped.

[0005] US 2017 / 0227030 A1 and WO 2006 / 111181 A1 describe conventional clamps whose hooks are adjacent to punched-out openings in the tape. However, the openings are designed without any positive effect on the load-holding properties of the hooks.

[0006] The object of the present invention is to improve the strength and stiffness of the connecting and / or tensioning hooks without having to accept disadvantages with regard to cost and usability of the tensioning clamp.

[0007] This problem is solved by the clamping clamp defined in claim 1. The further claims relate to preferred embodiments and a corresponding manufacturing process.

[0008] According to the invention, at least one of the connecting hook and the first and second clamping hooks is reinforced by a cut-out window. This window is formed by removing a two-dimensional area of ​​the clamping band from the flat band material, adjacent laterally to the edge section of the connecting hook and / or laterally to a tooth-like projection of at least one of the clamping hooks. When strong radial tensile forces are applied to the closed clamping clamp, the shape of the cut-out window distributes the material deformation stress acting on the band areas laterally adjacent to the edge section and / or the tooth-like projection more evenly, thereby preventing cracking even under high radial loads.

[0009] The hook's strength can be increased by radially extending at least part of the edge of the cut-out window, preferably at least 50% of the entire window edge. For example, at least three sides of the window edge are extended to create a radial protrusion. This allows the material deformation stress acting on the band areas laterally next to the edge area and / or the tooth-like projection to be distributed three-dimensionally, i.e., not only axially but also circumferentially along the radial extent of the raised band material. This strengthens the hooks and makes them more robust against deformation stresses.

[0010] In a preferred embodiment, the second clamping hook is reinforced by the claimed window opening. In this example, the entire window edge, with the exception of the sides or sections of the window opposite the tooth-like projection of the second clamping hook, is raised radially outwards, so that a hood-like or shell-shaped elevation is formed, with the tooth-like projection at the radially outermost end being designed as a point.

[0011] In another preferred example, the connecting hook is reinforced by the claimed window cutout. In this example, the entire edge of the cutout window is raised radially outwards to form a collar-like protrusion, with the edge section of the connecting hook forming a point at the radially outermost end.

[0012] Reinforcing the hooks through the window opening works particularly well if the window has rounded sections in the areas adjacent to the edge section and / or the toothed projection, especially two rounded, semicircular sections on either side of the edge section and / or the toothed projection. These semicircular or arc-shaped sections have an optimized load distribution profile.

[0013] The window may preferably also have a base section, which can be a rounded rectangular shape. The base section allows for uniform deformation of the material at the window edge during the manufacturing process of the clamp. This enables the side walls of the edge section and / or the toothed projection to be shaped so that, even under high radial stress, they rise in a smooth slope and a rounded geometry with a low tendency to crack. The base section and the arc-shaped corner sections of the window are arranged so that they surround the edge section and / or the toothed projection from both sides in the width direction and from one side in the circumferential direction of the clamp band. A finite element analysis (FEA) has shown particularly good load distribution for this geometry of the connecting hook (also called a "load-retaining hook") and / or the clamping hooks.

[0014] A particularly important embodiment of the invention (which can also be claimed independently of this window cutout in the connecting hook and / or the tensioning hooks – see the last part of this description) provides that the connecting hook and the first tensioning hook are arranged side by side in the circumferential direction at the first end section, such that a contact area between them has a curved shape, preferably a curved linear shape. In contrast to the connecting hook and the first tensioning hook, the contact area does not project radially out of the plane of the flat clamp band. The contact area has a curved shape, i.e., it generally extends in the width direction, but not in a straight line perpendicular to the longitudinal direction of the band. This helps to prevent kinking or bulging of the band material in the area between the connecting hook and the first tensioning hook when the tensioning clamp is tightened with a tensioning tool, e.g., a clamp.a pair of pliers, whose clamping jaws act on the first and second clamping hooks.

[0015] On both sides of the band area where the connecting hook and the first tensioning hook are formed, there are radially projecting side rails that help to further stiffen the band material and prevent buckling.

[0016] Embodiments of the invention are described in more detail below with reference to the drawings. These show: Fig. 1 a perspective view of the first end section of the clamp according to a first embodiment of the present invention in a flat (unbent) state; Fig. 2 a top view of the first end section in Fig. 1; Fig. 3 a side view of the in Fig. 1 shown first end section along the longitudinal extent of the clamp band; Fig. 4 a perspective view of the clamping clamp according to the embodiment of the present invention in a bent and pre-assembled state; Fig. a partial view of a portion of the flat strip material, where the cut-out window has been removed before the formation of the radial protrusions; Fig. 5B a partial view of the same part of the flat ribbon material as in Fig. 5A after forming the connecting hook; and Fig. 6 a perspective view of the second tension hook according to a second embodiment of the present invention.

[0017] In this description, the terms "radial," "axial," and "circumferential" refer to the overall geometric shape of the clamp, which, when closed, is generally a ring with a specific radius and circumference. The clamp is designed to enclose a pipe, hose, or sleeve that extends essentially in an axial direction.

[0018] The Fig. Figures 1-3 show the first circumferential end section 2 of the clamping clamp 10 in a flat (unbent) state. Fig. Figure 4 shows the complete clamp in a bent state and hooked in a pre-assembly position where the clamp radius is larger than in the final closed state.

[0019] The clamping clamp 10 is manufactured from a flat metal band or strip 1 by various cutting, forming, or embossing processes that are generally known in the art. The front end of the first circumferential end section 2 has a reduced width and forms a tongue section 11, which can be received in a tongue channel 19 on the inside of the second end section 3 of the band 1 (see Fig. 4) At the end of the tongue channel 19, stepped sections 17A, 17B are located on both sides, bearing against the side edges 14A, 14B formed on both sides at the end of the tongue section 11. The height of the radial step formed by the stepped sections 17A, 17B corresponds to the thickness of the flat strip material 1. Therefore, the closed clamp 10, in its closed state, offers a substantially stepless inner surface facing the object to be fastened.

[0020] Starting from the tongue section 11 in the circumferential direction towards the second end section 3 of the band 1, the clamping clamp 10 has a pre-assembly hook 12 which, in the pre-assembled state, can be received in an opening 42 of the second clamping hook 40 (see Fig. 4).

[0021] The combined arrangement of the connecting / load-holding hook 20 and the first tensioning hook 30 is located circumferentially next to the pre-assembly hook 12. The connecting hook 20 and the first tensioning hook 30 lie directly against each other in the circumferential direction along a curved contact line 28. While the connecting hook 20 and the first tensioning hook 30 both project radially from the plane of the undeformed strip material 1, the contact line 28 lies at the same level as the undeformed strip material 1. The connecting hook 20 has a centrally cut-out window 22, which will be referred to below with reference to the Fig. 5A and Fig. 5B is described in more detail.

[0022] The connecting hook 20 has a free edge section 21, which forms the radially outermost tip end of the hook 20 and serves as a locking tooth which, in the closed state of the clamping clamp 10, engages in the opening 42 of the second clamping hook 40 (see Fig. 4) can be received. The edge section 21 points circumferentially towards the second end section 3, so that it engages in the opening 42 when the two end sections 2 and 3 are pulled away from each other circumferentially in the closed state of the clamping clamp 1. The connecting hook 20 also has a rear surface in the circumferential direction opposite the window 22, which has a smooth radial inclination and forms a ramp for the outermost end of the second end section 3 during the closing process of the clamping clamp 10.

[0023] The first and second clamping hooks 30, 40 are both provided with tooth-like projections 31, 41 that point towards each other in the circumferential direction. These tooth-like projections 31, 41 enable the formation of a non-slip positive fit with the clamping jaws of a pair of pliers (not shown), which engage the first and second clamping hooks 30, 40 when the clamping clamp 10 is closed.

[0024] Side rails 13A, 13B are formed as additional stiffening ribs on the left and right sides of at least the portion of the first end section 2 on which the connecting hook 20 and the first tensioning hook 30 are formed. The side rails 13A, 13B are designed such that they extend substantially in the longitudinal direction (circumferential direction) of the strip material 1 and preferably reach up to the area in which the tongue section 11 is formed. This is intended to prevent the tongue section 11 from buckling when the tensioning clamp is closed.

[0025] The side rails 13A, 13B project radially inwards, i.e., in the radial direction opposite to that in which the connecting hook 20 and the first clamping hook 30 project. This not only improves the mechanical stability of the clamping clamp against buckling or bending in the area of ​​the connecting hook 20, but also ensures firm and uniform radial compression of the clamping clamp 10 against the object to be fastened along its entire inner circumference, including the critical area where the clamping and connecting hooks 20, 30, 40 are located.

[0026] The clamping clamp 10 is also provided with several tolerance compensation shafts 18 at the second end section 3. The curved radial shape of the tolerance compensation shafts 18 allows for the compensation of certain diameter variations in the clamping clamp 10 and the object to be fastened. The tolerance compensation shafts 18 also have an axial curvature, which allows at least part of the tolerance compensation shafts 18 to lie close to the object to be fastened, even if other parts of the tolerance compensation shafts 18 remain at a radial distance from the object to be fastened.

[0027] The manufacturing process of the tension hook 20 of the first embodiment is now described using the Fig. 5A and Fig. 5B is described in more detail. Fig. Figure 5A shows a portion of the flat metal strip material 1 in which the window 22 has been cut out. The window 22 is generally U-shaped and consists of a base section 23 in the form of a rounded rectangle and two rounded sections 24 arranged at two laterally opposite corners of the base section 23. Each of the two rounded sections 24 is arcuate and forms a semicircle, leaving a free border section 21 between them.

[0028] After cutting out the in Fig. In the window 22 shown in Figure 5A, the strip material 1 is deformed or embossed to raise the free edge section 21 and a complete edge of the window 22 radially outwards. This results in the Fig. Figure 5B shows the final collar-like shape of the connecting hook 20. Due to the rounded shape and the overall extent of the cut-out window 22 as a two-dimensional area, the cutting and embossing steps in the clamp manufacturing process are less prone to cracking compared to conventional clamp manufacturing. The shape of the connecting hook 20, with the window edge raised radially as a collar, also contributes to distributing the deformation stresses acting on the hook 20 evenly in three dimensions, i.e., not only in the axial and radial directions, but also in the circumferential direction.

[0029] FEA studies have also shown that the two rounded sections 24 and the raised outer edge of the window 22 give the connecting hook 20 optimized load and mechanical stress distribution properties. This results in increased stiffness and strength against radial forces, stresses, and impacts that may act on the free edge section 21 when the clamp is in the closed position. In particular, cracks in the lateral sections adjacent to the edge section 21 are much less likely because the sections 24 do not have sharp edges but rather a rounded, preferably semicircular, shape.

[0030] Instead of or in addition to the connecting hook 20 described in the first embodiment, one or both of the first and second tension hooks 30, 40 can also be reinforced by a window cutout. This is described as the second embodiment in the present [document / reference]. Fig. 6 for the second tension hook 40 is shown.

[0031] Starting from the same window shape with the base section 23 and the two rounded sections 24, which in Fig. shown, one can see the in Fig. The hook shape shown, with the cut-out window 43 and the tooth-like projection 41, is obtained. An additional cut of the strip material in the width direction of the strip (in Fig. (not shown) is required to form the opening 42. The use of the same window shape as in Fig. The connecting hook 20 shown in Figure 5B has the advantage that the same cutting / punching tool can be used for both windows 22, 43. However, other shapes can also be used that are optimized for the shape of the individual connecting and / or clamping hook and fall within the scope of the present invention. Furthermore, instead of or in addition to the connecting hook 20 and the second clamping hook 40, the first clamping hook 30 can also be provided with a cutout in the area of ​​the tooth-like projections 31, even though this is not shown in the drawings and the exemplary embodiments.

[0032] As in Fig.As shown, three of the four sides of the cut-out window frame are raised radially outwards. Only the side opposite the tooth-like projection 41 remains in the plane of the unraised strip material. In other words, the sides or edge sections of the window 43 that are closest to the axial side edges of the strip are raised in addition to the side where the tooth-like projection 41 forms a radial tip. This gives the second clamping hook 40 the shape of a cap or shell with arcuate side sections adjacent to the tooth-like projection 41. These arcuate side sections make it possible to distribute the deformation stress acting on the window edge not only radially and axially along the extent of the strip material, but also radially and circumferentially along the extent of the strip material.This makes the window 43 more resistant to external stress forces and improves the load-holding properties of the second tension hook 40.

[0033] The present invention relates, alternatively and independently of a specific shape of the connecting hook 20 and the first and second clamping hooks 30, 40, also to the curved contact area 28 between the connecting hook 20 and the first clamping hook 30 as a main feature. In particular, the present invention is also directed to the following points: [1] Clamping clamp (10) made from a clamp band (1) with first and second circumferential end sections (2, 3) which overlap each other in a closed state of the clamping clamp (10), wherein the clamping clamp (10) comprises: a connecting hook (20) which projects radially outwards from the first end section (2), a first tension hook (30) which projects radially outwards at the first end section (2), and a second clamping hook (40) which projects radially outwards from the second end section (3) and has an opening (42) for receiving an edge section (21) of the connecting hook (20) in the closed state of the clamping clamp (10), wherein the connecting hook (20) and the first tensioning hook (30) are arranged side by side in the circumferential direction on the first end section (2), characterized in that a contact area (28) between the connecting hook (20) and the first clamping hook (30) has a curved shape, preferably a curved line shape. [2] Clamping clamp (10) according to [1], in which the contact area (28) does not extend radially beyond the plane of the flat clamp band (1). [3] Clamping clamp (10) according to [1] or [2], wherein at least one of the connecting hook (20) and the first and second clamping hooks (30, 40) has a cut-out window (22, 43) in which a two-dimensional area of ​​material is removed from the clamp band (1). [4] Clamping clamp (10) according to [3], wherein the window (22, 43) has rounded sections (24) in areas laterally adjacent to the edge section (21) and / or the tooth-like projection (31, 41) of the first or second clamping hook (30, 40). [5] Clamping clamp (10) according to [4], wherein the rounded sections (24) have a semicircular shape. [6] Clamping clamp (10) according to [4] or [5], wherein the window (22, 43) has a base section (23) in a region which is adjacent in the circumferential direction to the edge section (21) and / or the tooth-like projection (31, 41) of the first or the second clamping hook (30, 40) in the direction towards the other end region (3, 2). [7] Clamping clamp (10) according to [6], wherein the base section (23) has the shape of a rectangle with rounded corners. [8] Clamping clamp (10) according to one of the points [4] to [7], wherein the window (22, 43) surrounds the edge section (21) of the connecting hook (20) and / or the tooth-like projection (31, 41) of the first or the second clamping hook (30, 40) from both sides in the width direction and from one side in the circumferential direction of the clamp band (1). [9] Clamp (10) according to one of points [1] to [8], which also includes the following radially projecting side rails (13A, 13B) on the first end section (2) on both sides of the band area in which the connecting hook (20) and the first tensioning hook (30) are formed, and / or a tongue section (11) formed at the circumferential end of the first end section (2) and configured to be inserted into a tongue channel (19) formed at the second end section (3), and / or at least one radially outward projecting tolerance compensation shaft (18), which is preferably formed on the second end section (3) and is optionally curved in the axial direction. Reference symbol list 1 Flat ribbon material 2 first end 3 second end 10 clamps 11 Tongue section 12 pre-assembly hooks 13A, 13B Side rails 14A, 14B Side edges 17A, 17B stepped section 18 tolerance compensation shafts 19 Tongue canal 20 connecting hooks 21 preceding marginal note 22 Window cutout (U-shaped) 23 Base section (rounded rectangle) 24 tip sections (semicircular) 28 Contact area (curved line) 30 first tension hook 31 tooth projections 40 second tension hook 41 tooth projection 42 Opening 43 Window section QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 2009 / 0313792 A1

[0002] WO 2018 / 082819 A1

[0003] US 2017 / 0227030 A1

[0005] WO 2006 / 111181 A1

[0005]

Claims

[1] Clamp (10) made of a clamp band (1) with first and second circumferential end portions (2, 3) which overlap one another in a closed state of the clamp (10), the clamp (10) comprising: a connecting hook (20) which projects radially outwards at the first end portion (2), a first clamping hook (30) which projects radially outwards at the first end section (2), and a second clamping hook (40) which projects radially outwards at the second end portion (3) and has an opening (42) for receiving an edge portion (21) of the connecting hook (20) in the closed state of the clamp (10), characterized by that at least one of the connecting hook (20) and the first and second clamping hooks (30, 40) has a cut-out window (22, 43) in which a two-dimensional region of material is removed from the clamp band (1). [2] Clamp (10) according to claim 1, wherein at least parts of the edge of the cut-out window (22, 43), preferably at least 50% of the entire window edge, are raised radially outwards. [3] Clamp (10) according to claim 2, wherein the entire window edge, with the exception of the sides or sections of the window (43) which are opposite a tooth-like projection (41) of the second clamping hook (40), is raised radially outwards so that a hood-like or shell-shaped elevation is formed with a tip formed by the tooth-like projection (41) of the second clamping hook (40). [4] Clamp (10) according to claim 2, wherein the entire edge of the cut-out window (22) is raised radially outward to form a collar-like elevation with a tip formed by the edge portion (21) of the connecting hook (20). [5] Clamp (10) according to one of the preceding claims, characterized bythat the window (22, 43) has rounded sections (24) in areas laterally adjacent to the edge section (21) and / or has a tooth-like projection (31, 41) of the first or the second clamping hook (30, 40). [6] Clamp (10) according to claim 5, wherein the rounded portions (24) have a semicircular shape. [7] Clamp (10) according to claim 5 or 6, characterized by that the window (22, 43) has a base portion (23) in a region which borders the edge portion (21) and / or the tooth-like projection (31, 41) of the first or second clamping hook (30, 40) in the circumferential direction, in the direction of the other end portion (3, 2). [8] Clamp (10) according to claim 7, wherein the base portion (23) has the shape of a rectangle with rounded corners. [9] Clamp (10) according to one of claims 5 to 8, wherein the window (22, 43) surrounds the edge portion (21) of the connecting hook (20) and / or the tooth-like projection (31, 41) of the first or second clamping hook (30, 40) from both sides in the width direction and from one side in the circumferential direction of the clamp band (1). [10] Clamp (10) according to one of the preceding claims, wherein the connecting hook (20) and the first clamping hook (30) are arranged adjacent to each other in the circumferential direction at the first end section (2), and a contact area (28) between the connecting hook (20) and the first clamping hook (30) has a curved shape, preferably a curved line shape. [11] Clamp (10) according to claim 10, wherein the contact region (28) does not project radially beyond the plane of the flat clamp band (1). [12] Clamp (10) according to one of the preceding claims, further comprising: radially projecting side rails (13A, 13B) at the first end portion (2) on both sides of the band area in which the connecting hook (20) and the first tensioning hook (30) are formed. [13] Clamp (10) according to one of the preceding claims, further comprising: a tongue portion (11) formed at the peripheral end of the first end portion (2) and configured to be inserted into a tongue channel (19) formed at the second end portion (3). [14] Clamp (10) according to one of the preceding claims, further comprising: at least one radially outwardly projecting tolerance compensation shaft (18), which is preferably formed on the second end section (3) and is optionally curved in the axial direction. [15] A method for forming a clamp (10) from a flat clamp band (1) having first and second circumferential end portions (2, 3) configured to overlap in a closed state of the clamp (10), the method comprising: Removing a two-dimensional area of ​​the material from the clamp band (1) to form a cut-out window (22, 43), Forming the clamp band (1) to provide a connecting hook (20) which projects radially outwards at the first end section (2), Forming the clamp band (1) to provide a first clamping hook (30) which projects radially outward at the first end portion (2), and Forming the clamp band (1) to provide a second clamping hook (40) which projects radially outwards at the second end portion (3) and has an opening (42) for receiving an edge portion (21) of the connecting hook (20) in the closed state of the clamp (10), characterized by that at least one of the connecting hook (20) and the first and second tensioning hooks (30, 40) is formed in a region surrounding the cut-out window (22, 43).

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