Clamp with stronger closing hook design

Abstract

The invention relates to a clamp (10) made of a clamping band (1) having a first and a second circumferential end (2, 3) which overlap one another in the closed state of the clamp (10). The clamp (10) comprises a connecting hook (20) projecting radially outward at a first end (2), a first tensioning hook (30) projecting radially outward at the first end (2), and a second tensioning hook (40) projecting radially outward at a second end (3), and the second tensioning hook (40) has an aperture (42) for receiving an edge portion (21) of the connecting hook (20) in a closed state of the clamp (10). At least one of the connecting hook (20) and the first and second tensioning hook (30, 40) has a cut-out window (22, 43), a two-dimensional material region being removed from the clamping band (1), and the cut-out window (22, 43) preferably having a circular arc-shaped portion (24) in a region laterally adjacent to an edge portion (21) of the connecting hook (20) and / or a toothing (31, 41) of the first or second tensioning hook (30, 40), when the clamp (10) must be subjected to high radial expansion force, the tooth-shaped protrusions (31, 41) are prevented from cracking at these parts.

Description

Technical Field

[0001] The present invention relates to a clamp made of a flat metal band or strip which forms a loop for tightening around an object with a substantially circular cross section, such as a hose, a pipe or a sheath. In particular, the present invention relates to a so-called "low profile clamp", i.e. a clamp having only a small radially outwardly protruding portion, resulting in a relatively small overall radial clamp profile. Furthermore, the present invention particularly relates to a so-called step-free clamp, i.e. a clamp having almost no uneven portions or steps at the inner surface in the closed state. Background Art

[0002] US 2009 / 0313792 A1 discloses a conventional clamp having a connecting hook (fastening stud) protruding radially outward near a first end of a strip and a tensioning hook (fastening ear) protruding radially outward near a second end of the strip and provided with a hole into which a free end edge portion of the connecting hook can be inserted in order to tighten and secure the clamp when the fastening ear is assembled on a foot portion of the connecting hook.

[0003] WO 2018 / 082819 A1 gives another example of such a conventional clamp, which has a closing hook in the form of a connecting hook and two tensioning hooks for fastening the clamp around an object to be fastened by a fastening tool (such as pliers).

[0004] A disadvantage encountered with these conventional clamps is that the load holding properties of their closing hooks are insufficient. When the closed clamp is subjected to high radial expansion forces, the edge portions of the connecting hooks and / or the tensioning hooks tend to deform and / or cracks appear in the belt material at the lateral sides of the edge portions. Furthermore, in the hook manufacturing process for conventional clamps, cracks may already appear during the cutting and embossing steps.

[0005] US 2017 / 0227030A1 and WO 2006 / 111181 A1 describe conventional clamps whose hooks are adjacent to punched-out belt openings. However, the openings provided have no positive effect on the load-holding properties of the hooks. Summary of the invention

[0006] The object of the present invention is to increase the strength and rigidity of a connecting hook and / or a tensioning hook without compromising the cost and usability of the clamp.

[0007] This object is achieved by the clamp defined in claim 1. The other claims relate to preferred embodiments and corresponding production methods.

[0008] According to the invention, the connecting hook and at least one of the first and second tensioning hooks are reinforced by a cut-out window formed by removing from the flat clamping band a two-dimensional area of ​​band material laterally adjacent to an edge portion of the connecting hook and / or laterally adjacent to a toothing of at least one of the tensioning hooks. When the closed clamp is subjected to high radial expansion forces, the shape of the cut-out window distributes the material deformation stresses acting on the band areas laterally adjacent to the edge portion and / or the toothing more evenly, thereby avoiding cracking even under high radial stresses.

[0009] The reinforcing effect of the hook can be enhanced when at least a portion of the edge of the cut-out window (preferably at least 50% of the entire window edge) is radially outwardly protruding. For example, at least three sides of the window edge are protruding so as to form a radial protrusion. This allows to distribute the material deformation stresses acting on the strip area laterally adjacent to the edge portion and / or the tooth-like protrusion in a three-dimensional direction, i.e. not only in the axial direction, but also in the circumferential direction along the radial extension of the protruding strip material. As a result, the hook is reinforced and becomes more robust against deformation stresses.

[0010] In a preferred example, the second tensioning hook is reinforced by a cut-out window as claimed. According to this example, all window edges except the side or portion of the window opposite to the tooth-like protrusion of the second tensioning hook are radially protruded outward to form a crown or shell-like protrusion, wherein the tooth-like protrusion is formed as a peak at the radial tip.

[0011] In another preferred example, the connecting hook is reinforced by the cut-out window claimed. According to this example, the entire edge of the cut-out window protrudes radially outward to form a collar-like protrusion, wherein the edge portion of the connecting hook is formed as a peak at the radial tip.

[0012] The reinforcement effect of the hook by the cut-out window is particularly good when the window has a rounded portion in the area laterally adjacent to the edge portion and / or the toothing, in particular two rounded portions of semicircular shape at either lateral side close to the edge portion and / or the toothing. Semicircular or arcuate portions already show an optimized load distribution profile.

[0013] The window may preferably further have a base portion, which may have a rounded rectangular shape. The base portion allows for smooth deformation of the material at the edge of the window during the manufacturing process of the clamp. Thus, the side walls of the edge portion and / or the toothed protrusions can be formed to rise with a smooth slope and a rounded geometry, with a low tendency to crack even under high radial stresses. The base portion and the arcuate corners of the window are arranged so that they surround the edge portion and / or the toothed protrusions from both lateral sides in the width direction and from one side in the circumferential direction of the clamping band. Finite element analysis (FEA) has provided particularly good load distribution for such a geometry of the connecting hook (also called "load holding hook") and / or the tensioning hook.

[0014] A particularly important embodiment of the invention (which can also be claimed independently of any window in the connecting hook and / or the tensioning hook, see the end of this description) requires that the connecting hook and the first tensioning hook are positioned circumferentially adjacent to each other on the first end so that the contact area between them has a curved shape, preferably a curvilinear shape. Unlike the connecting hook and the first tensioning hook, the contact area does not protrude radially from the horizontal plane of the flat clamping strip. The contact area has a curved shape, i.e. it extends approximately in the width direction, but not in a straight line perpendicular to the longitudinal direction of the strip. This helps to avoid kinking or buckling of the strip material in the area between the connecting hook and the first tensioning hook when the clamp is closed by a tightening tool, for example a pliers with jaws acting on the first and second tensioning hooks.

[0015] Radially protruding side rails, which are formed at both lateral sides of the belt region in which the connecting hook and the first tensioning hook are formed, help to further strengthen the belt material and avoid buckling. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Embodiments of the present invention will now be described in more detail below with reference to the accompanying drawings, in which:

[0017] Figure 1 is a perspective view of a first end portion of a clamp according to a first embodiment of the present invention in a flat (non-circular) state;

[0018] Figure 2 yes Figure 1 a top view of the first end portion shown;

[0019] Figure 3 yes Figure 1 A side view of the first end portion shown extending in the longitudinal direction of the clamping band;

[0020] Figure 4 is a three-dimensional diagram of a clamp according to an embodiment of the present invention in a circular state and a pre-assembled state;

[0021] Figure 5Ais a partial view of a portion of a flat strip material with cut-out windows removed prior to forming radial protrusions;

[0022] Figure 5B After the connection hook is formed Figure 5A a partial view of the same portion of the flat strip material in FIG. 1 ; and

[0023] Figure 6 is a perspective view of a second tensioning hook according to a second embodiment of the present invention.

[0024] In this specification, the terms "radial", "axial" and "circumferential" refer to the overall geometry of the clamp, which in its closed state is generally a ring with a certain radius and circumference. The clamp is designed to enclose a pipe, hose or sheath extending substantially in the axial direction. DETAILED DESCRIPTION

[0025] Figures 1 to 3 The first circumferential end 2 of the clamp 10 is shown in a flattened (non-circular) state. Figure 4 The complete clamp is shown in a circular state and hooked in a pre-assembly position in which the clamp radius is larger than in the final closed state.

[0026] The clamp 10 is made of a flat metal strip or strip 1 by various cutting and deforming or embossing steps generally known in the art. The first circumferential end 2 terminates with a reduced width and forms a tongue-shaped portion 11 adapted to be received in a tongue-shaped channel 19 at the inner side of the second end 3 of the strip 1 (see Figure 4 ). At the end of the tongue-shaped channel 19, there are step portions 17A, 17B on both lateral sides for abutting against the side edges 14A, 14B formed on both lateral sides at the end of the tongue-shaped portion 11. The height of the radial step formed by the step portions 17A, 17B corresponds to the thickness of the flat strip material 1. Thus, the closed clamp 10 in its closed state provides a substantially step-free inner surface facing the object to be fastened.

[0027] Extending circumferentially from the tongue portion 11 in the direction of the second end 3 of the belt 1, the clamp 10 has a pre-assembly hook 12 which is adapted to be received in the aperture 42 of the second tensioning hook 40 in the pre-assembly state (see Figure 4 ).

[0028] Circumferentially adjacent to the preassembly hook 12 is a combined arrangement of a connecting hook or load holding hook 20 and a first tensioning hook 30. The connecting hook 20 and the first tensioning hook 30 are in direct contact with each other in the circumferential direction at a curved contact line 28. Although both the connecting hook 20 and the first tensioning hook 30 protrude radially from the level of the undeformed strip material 1, the contact line 28 is at the same level as the undeformed strip material 1. The connecting hook 20 has a centrally cut-out window 22, which will be described below for reference. Figure 5A and 5B Describe in more detail.

[0029] The connecting hook 20 has a free edge portion 21 which forms the radially outermost tip of the connecting hook 20 and serves as an engaging tooth which is adapted to be received in the aperture 42 of the second tensioning hook 40 in the closed state of the clamp 10 (see Figure 4 ). The edge portion 21 points in the circumferential direction toward the second end portion 3 so that when the two ends 2 and 3 are pulled circumferentially away from each other in the closed state of the clamp 1, the edge portion 21 hooks into the aperture 42. The connecting hook 20 also has a rear surface in the circumferential direction opposite to the window 22, which has a smooth radial bevel and provides a slope for the outermost end of the second end portion 3 during the closing operation of the clamp 10.

[0030] The first and second tensioning hooks 30, 40 are each provided with toothed projections 31, 41 facing each other in the circumferential direction. These toothed projections 31, 41 allow a non-slip form fit with the jaws of a pliers (not shown) that engages with the first and second tensioning hooks 30, 40 in the closing operation of the clamp 10.

[0031] The side rails 13A, 13B are formed as additional reinforcing ribs at the left and right lateral sides of at least the portion of the first end portion 2 where the connecting hook 20 and the first tensioning hook 30 are formed. The side rails 13A, 13B are formed to extend substantially in the longitudinal (= circumferential) direction of the belt material 1, and preferably to the region where the tongue portion 11 is formed. This is to avoid kinking of the tongue portion 11 during clamp closing.

[0032] The side rails 13A, 13B protrude radially inwards, i.e. in a radial direction opposite to the radial direction into which the connecting hooks 20 and the first tensioning hooks 30 protrude. Thus, the side rails 13A, 13B not only improve the mechanical stability of the clamp against buckling or bending in the region of the connecting hooks 20. The fact that the side rails 13A, 13B protrude radially inwards also ensures a firm and uniform radial compression of the clamp 10 against the object to be fastened along the entire inner circumference, including the critical portion forming the tensioning hooks and the connecting hooks 20, 30, 40.

[0033] The clamp 10 is also provided with a plurality of tolerance compensating undulations 18 at the second end 3. The curved radial shape of the tolerance compensating undulations 18 allows compensation for certain diameter variations of the clamp 10 and the object to be fastened. The tolerance compensating undulations 18 also have a curvature in the axial direction, which allows at least a portion of the tolerance compensating undulations 18 to fit tightly on the object to be fastened, even when other portions of the tolerance compensating undulations 18 are held at a radial distance from the object to be fastened.

[0034] Now we will use Figure 5A and 5B The manufacturing process of the tensioning hook 20 of the first embodiment will be described in more detail. Figure 5A A portion of a planar metal strip material 1 is shown, in which a window 22 is cut out. The window 22 is generally U-shaped and consists of a base portion 23 having a rounded rectangular shape and two rounded portions 24 located at two laterally opposite corners of the base portion 23. Each of the two rounded portions 24 is arc-shaped and forms a semicircle, so that a free edge portion 21 is formed therebetween.

[0035] In cut out Figure 5A After the window 22 shown, the belt material 1 is deformed or embossed to raise the free edge portion 21 and the entire edge of the window 22 radially outward. This results in Figure 5B . Due to the circular shape of the cut-out window 22 and the overall extension as a two-dimensional area, the cutting and stamping steps in the fixture manufacturing process have a lower tendency to generate cracks compared to conventional fixture manufacturing. In addition, the shape of the connecting hook 20 with the window edge rising as a collar in the radial direction helps to evenly distribute any deformation stress acting on the connecting hook 20 in three dimensions, that is, not only in the axial and radial directions but also in the circumferential direction.

[0036] FEA studies have also shown that the two circular portions 24 and the raised outer edge of the window 22 provide optimized distribution characteristics of loads and mechanical stresses for the connecting hook 20. It thus has increased rigidity and strength to resist radial forces, stresses and impacts that may act on the free edge portion 21 during use of the clamp in the closed configuration. In particular, due to the fact that the portion 24 has no sharp edges but has a rounded (preferably semi-circular) shape, cracks at the lateral side portions close to the edge portion 21 are less likely to occur.

[0037] Instead of or in addition to the connecting hook 20 as described in the first embodiment, one or both of the first tensioning hook 30 and the second tensioning hook 40 may be reinforced by a cut-out window. Figure 6 A second embodiment of a second tensioning hook 40 is shown in FIG.

[0038] From having Figure 5A Starting from the same window shape of the base portion 23 and the two circular portions 24 shown, it is possible to obtain a window having Figure 6 The cut-out windows 43 and hook design of the tooth-like protrusions 41 shown require additional cutting of the belt material in the width direction of the belt ( Figure 5A (not shown) to form the orifice 42. Figure 5B The same window shape of the connecting hook 20 shown in the figure provides the advantage that the same cutting / punching tool can be used for both windows 22, 43. However, different shapes optimized for the shape of the respective connecting hook and / or tensioning hook can be used and fall within the scope of the invention. Furthermore, instead of the connecting hook 20 or in addition to the second tensioning hook 40, the first tensioning hook 30 can also be provided with a cut-out window in the area adjacent to the tooth-like protrusion 31, even if this is not shown in the figures and the detailed embodiments.

[0039] like Figure 6 As shown, three of the four sides of the cut-out window frame are radially outwardly convex. Only the side opposite to the tooth-like protrusion 41 remains in the plane of the non-convex belt material. In other words, the side or edge portion of the window 43 closest to the axial side edge of the belt is raised, except for the side where the tooth-like protrusion 41 is formed as a radial peak. Thus, the second tensioning hook 40 is formed to have the shape of a canopy or shell with arc-shaped sides adjacent to the tooth-like protrusion 41. These arc-shaped sides allow the deformation stress acting on the edge of the window to be distributed not only radially and axially along the extension of the belt material, but also radially and circumferentially along the extension of the belt material. As a result, the window 43 becomes more resistant to external stresses and the load holding properties of the second tensioning hook 40 are improved.

[0040] As an alternative to any specific shape of the connecting hook 20 and the first tensioning hook 30 and the second tensioning hook 40, the present invention also covers the curved contact portion 28 between the connecting hook 20 and the first tensioning hook 30 as a main feature. In particular, the present invention also relates to:

[0041] [1] A clamp (10) made of a clamping band (1), the clamping band (1) having first and second circumferential ends (2, 3), the first and second circumferential ends (2, 3) overlapping each other in a closed state of the clamp (10), the clamp (10) comprising:

[0042] a connecting hook (20) which projects radially outward at the first end (2),

[0043] a first tensioning hook (30) protruding radially outward at the first end (2), and

[0044] a second tensioning hook (40) which projects radially outwards at the second end (3) and has an orifice (42) for receiving an edge portion (21) of the connecting hook (20) in the closed state of the clamp (10),

[0045] wherein the connecting hook (20) and the first tensioning hook (30) are positioned adjacent to each other in the circumferential direction on the first end portion (2),

[0046] It is characterized in that the contact area (28) between the connecting hook (20) and the first tensioning hook (30) has a bent shape, preferably a curved shape.

[0047] [2] The clamp (10) according to [1], wherein the contact area (28) does not protrude radially from the horizontal plane of the flat clamping band (1).

[0048] [3] The clamp (10) according to [1] or [2], wherein the connecting hook (20) and at least one of the first tensioning hook (30) and the second tensioning hook (40) have a cut-out window (22, 43), in which a two-dimensional material area is removed from the clamping band (1).

[0049] [4] The clamp (10) according to [3], wherein the window (22, 43) has a rounded portion (24) in an area laterally adjacent to the edge portion (21) and / or the tooth-like protrusion (31, 41) of the first tensioning hook (30) or the second tensioning hook (40).

[0050] [5] The jig (10) according to [4], wherein the circular portion (24) has a semicircular shape.

[0051] [6] The clamp (10) according to [4] or [5], wherein the window (22, 43) has a base portion (23) in the area circumferentially adjacent to the edge portion (21) and / or the toothed protrusion (31, 41) of the first tensioning hook (30) or the second tensioning hook (40) in the direction toward the other end (3, 2).

[0052] [7] The clamp (10) according to [6], wherein the base portion (23) has a rectangular shape with rounded corners.

[0053] [8] A clamp (10) according to any one of [4] to [7], wherein the window (22, 43) surrounds the edge portion (21) of the connecting hook (20) and / or the tooth-like protrusions (31, 41) of the first tensioning hook (30) or the second tensioning hook (40) from two lateral sides in the width direction and one side in the circumferential direction of the clamping band (1).

[0054] [9] The clamp (10) according to any one of [1] to [8], further comprising:

[0055] radially projecting side rails (13A, 13B) formed on the first end (2) at both lateral sides of the belt region in which the connecting hook (20) and the first tensioning hook (30) are formed, and / or

[0056] a tongue-shaped portion (11) formed at a circumferential end of the first end portion (2) and configured to be inserted into a tongue-shaped channel (19) formed at the second end portion (3), and / or

[0057] At least one tolerance compensating wave (18) protruding radially outwards is preferably formed at the second end (3) and is optionally curved in the axial direction.

[0058] Reference numerals list

[0059] 1Flat belt material

[0060] 2First end

[0061] 3 Second end

[0062] 10 Clamp

[0063] 11Tongue-shaped part

[0064] 12 pre-assembled hooks

[0065] 13A, 13B side rails

[0066] 14A, 14B side edges

[0067] 17A, 17B steps

[0068] 18 Tolerance compensation corrugated part

[0069] 19 Tongue-shaped channel

[0070] 20 Connecting hooks

[0071] 21Protruding edge part

[0072] 22 Cut-out window (U-shaped)

[0073] 23 base part (rounded rectangle)

[0074] 24 Tip part (semicircular)

[0075] 28 Contact area (curve)

[0076] 30 The first tight hook

[0077] 31 denticles

[0078] 40 Second tension hook

[0079] 41 denticles

[0080] 42 orifices

[0081] 43 Cut-out Window

Claims

1. A clamp (10) made of a clamping band (1), the clamping band (1) having a first and a second circumferential end portion (2, 3), the first and second circumferential end portions (2, 3) overlapping each other in a closed state of the clamp (10), the clamp (10) comprising: a connecting hook (20) which projects radially outward at the first end (2), a first tensioning hook (30) which projects radially outward at the first end (2), and a second tensioning hook (40) which projects radially outwards at the second end (3) and has an orifice (42) for receiving an edge portion (21) of the connecting hook (20) in the closed state of the clamp (10), Characterized in that the connecting hook (20) and at least one of the first tensioning hook (30) and the second tensioning hook (40) have a cut-out window (22, 43) in which a two-dimensional material area is removed from the clamping band (1).

2. The clamp (10) according to claim 1, wherein: At least part of the edge of the cut-out window (22, 43), preferably at least 50% of the entire window edge, bulges radially outward.

3. The clamp (10) according to claim 2, wherein: Except for the side or portion of the window (43) opposite to the tooth-like protrusion (41) of the second tensioning hook (40), the entire window edge protrudes radially outward to form a canopy or shell-like protrusion having a peak formed by the tooth-like protrusion (41) of the second tensioning hook (40).

4. The clamp (10) according to claim 2, wherein: The entire edge of the cut-out window (22) bulges radially outward to form a collar-like protrusion having a peak formed by an edge portion (21) of the connecting hook (20).

5. The clamp (10) according to any one of the preceding claims, wherein: The window (22, 43) has a rounded portion (24) in a region laterally adjacent to the edge portion (21) and / or the toothed projections (31, 41) of the first or second tensioning hook (30, 40).

6. The clamp (10) according to claim 5, wherein: The circular portion (24) has a semicircular shape.

7. The clamp (10) according to claim 5 or 6, wherein: The window (22, 43) has a base portion (23) in a region circumferentially adjacent to the edge portion (21) and / or the toothed protrusion (31, 41) of the first tensioning hook (30) or the second tensioning hook (40) in the direction toward the other end (3, 2).

8. The clamp (10) according to claim 7, wherein: The base portion (23) has a rounded rectangular shape.

9. The clamp (10) according to any one of claims 5 to 8, wherein: The window (22, 43) surrounds the edge portion (21) of the connecting hook (20) and / or the toothed protrusions (31, 41) of the first tensioning hook (30) or the second tensioning hook (40) from both lateral sides in the width direction of the clamping band (1) and from one side in the circumferential direction.

10. The clamp (10) according to any one of the preceding claims, wherein: The connecting hook (20) and the first tensioning hook (30) are positioned adjacent to each other in the circumferential direction on the first end portion (2), and The contact area (28) between the connecting hook (20) and the first tensioning hook (30) has a curved shape, preferably a curvilinear shape.

11. The clamp (10) according to claim 10, wherein: The contact area (28) does not protrude radially from the horizontal plane of the flat clamping band (1).

12. The clamp (10) according to any one of the preceding claims, further comprising: Radially projecting side rails (13A, 13B) are formed on the first end (2) at both lateral sides of the strip-shaped area in which the connecting hook (20) and the first tensioning hook (30) are formed.

13. The clamp (10) according to any one of the preceding claims, further comprising: A tongue portion (11) is formed at a circumferential end of the first end portion (2) and is configured to be inserted into a tongue channel (19) formed at the second end portion (3).

14. The clamp (10) according to any one of the preceding claims, further comprising: At least one tolerance compensating wave (18) protruding radially outwards is preferably formed at the second end (3) and is optionally curved in the axial direction.

15. A method for forming a clamp (10) from a flat clamping band (1), the flat clamping band (1) having a first circumferential end (2) and a second circumferential end (3), the first circumferential end (2) and the second circumferential end (3) being arranged to overlap each other in a closed state of the clamp (10), the method comprising: removing a two-dimensional material region from the clamping band (1) to form a cut-out window (22, 43), The clamping band (1) is formed to provide a connecting hook (20) which projects radially outwards at the first end (2), The clamping band (1) is formed to provide a first tensioning hook (30) which projects radially outwardly at the first end (2); as well as The clamping strip (1) is formed to provide a second tensioning hook (40) which projects radially outwards at the second end (3) and has an aperture (42) for receiving an edge portion (21) of the connecting hook (20) in the closed state of the clamp (10), It is characterized in that the connecting hook (20) and at least one of the first tensioning hook (30) and the second tensioning hook (40) are formed in a region surrounding the cut-out window (22, 43).

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