Centering features in low profile clamp

Abstract

The invention discloses a centering feature in a low profile clamp. A low profile clip (10) in which one or both contact surfaces (25, 45) of upper and lower circumferential ends (2, 3) have a non-flat and preferably complementary cross-sectional shape in the width direction of the strip material (1). Thus, sliding contact of the upper contact surface (45) on the lower contact surface (25) provides a self-centering effect of the belt ends (2, 3) during a belt closing action.

Description

Technical Field

[0001] The present invention relates to a clamp made of a flat metal band or strip formed into a loop for fastening around an object of generally circular cross-section such as a hose, tube or sheath. In particular, the present invention relates to so-called "low profile clamps", i.e. such clamps whose hook elements protrude radially outwards only to a limited extent, resulting in a relatively small overall radial clamp profile.

[0002] Furthermore, the invention relates in particular to so-called step-free clamps, ie clamps which have virtually no uneven parts or steps on the inner surface in their closed state. Background Art

[0003] Examples of such stepless clamps are provided in US 5 669 113 A and WO 2009 / 152832 A1. The clamps have outwardly protruding ears which can be crimped by a crimping tool to securely fasten the clamp around the object to be fastened.

[0004] US 2009 / 0313792 A1 discloses a conventional clip 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 the tensioning hook (fastening ear) is provided with a hole into which a free end edge portion of the connecting hook can be inserted so as to fasten and tighten the clip, while the fastening ear fits on the foot of the connecting hook.

[0005] 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 tightening the clamp around an object to be tightened by a tightening tool such as pliers.

[0006] These conventional low profile clips have the disadvantage that during the closing action, in particular in the final stages of the closing action when the highest closing forces are applied, axial misalignment may occur. This may result in an unreliable engagement of the upper and lower strap end portions. As a result, this weakens the impact resistance of the clip, i.e. it carries the risk of the hook element being detached due to an impact of an external force. Summary of the invention

[0007] One object of the present invention is to improve the correct alignment of the connecting elements during the closing action.By ensuring that the tensioning hook is circumferentially parallel to the connecting hook, the clamp should properly and safely reach the closed state.

[0008] This object is achieved by the clamp defined in claim 1. The other claims relate to preferred embodiments.

[0009] According to the invention, a centering feature at the upper strap end prevents misalignment of the strap end during closing of the low-profile clamp. In particular, the centering feature consists in a contact surface with a non-flat cross section provided at the upper strap end, which contact surface is arranged to come into sliding contact with a contact surface at the lower strap end during the strap closing action, i.e. when the clamp is brought into a closed state by pulling the first and second tensioning hooks circumferentially towards each other. The proposed solution enables centering of the upper strap relative to the connecting hooks (also called load holding hooks) on the lower strap.

[0010] Preferably, the contact surfaces with a non-flat cross section are provided on radially opposite portions of both the upper and lower belt ends, and more preferably, the cross-sectional shapes of the two contact surfaces are complementary to each other. Thus, the radially opposite portions at the two belt ends contribute to the desired centering. The two contact surfaces are preferably provided only in the central portion of the clamping belt in the width direction.

[0011] In a preferred example, the cross section of the contact surface has a circular shape, in particular the shape of a ring segment. In other words, the contact surface forms an arc when viewed in the axial direction of the measuring bandwidth. This cross-sectional shape has proven to be the most effective for obtaining a smooth and evenly distributed centering effect over the entire width of the contact surface.

[0012] According to the proposed solution, the upper (second) contact surface has a rounded shape on the inside, which approximately matches the outer (first) surface of the load holding (or connecting) hook. This allows, during the closing of the clip, the belt end to be guided to a centered position relative to the load holding hook. In the proposed shape (including other shapes leading to the same functionality), the rounded surface allows to center the belt end during the closing of the clip by a guided sliding on the load holding hook outer surface. This prevents an undesired misaligned closing of the clip (uncentered engagement of the belt end with the load holding hook feature). Different non-flat cross-sectional shapes (not only round, but also other shapes) can be used, preferably when the lower belt end surface matches the upper load holding hook surface.

[0013] In the most preferred example, the non-flat cross section of the contact surface extends up to the area immediately adjacent to the hole side of the tensioning hook at the upper belt end. In other words, the centering feature is arranged just before the engagement surface. Thus, the guiding effect occurs until the end of the closing stroke, i.e., at the time when the closing force acting on the belt is the greatest and the risk of misalignment is the highest.

[0014] In another preferred example, the upper end portion of the belt has a radially protruding free end, and the contact surface is arranged in a region circumferentially located between the hole of the tensioning hook and the radially protruding free end. This further improves the smoothness of the interaction of the free end with the closing hook at the beginning of the closing action. In order to obtain a seamless continuation of the closing action, the region immediately adjacent to the contact surface in the width direction is at the same radial height as the protruding free end and extends circumferentially at this height up to the protruding free end.

[0015] In a further optimized embodiment of the invention, the connecting hook is provided with additional guiding elements. In addition to the central ramp portion with the claimed lower contact surface, the connecting hook may have one or more guiding elements adjacent to the central ramp in the width direction. These guiding elements allow centering of the upper end portion during the closing action and may preferably form a groove towards the ramp portion, which groove has a funnel-like shape. This shape of the connecting (or load holding) hook further improves the centered guidance of the belt end during the closing stroke. 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 side view of a conventional (i.e., prior art) low profile clip in a circular and pre-assembled state;

[0018] Figure 2 Is in a flat (not rounded) state Figure 1 A top view of a conventional low profile clamp;

[0019] Figure 3A yes Figure 2 An enlarged top view of an area X at a second end of the clip;

[0020] Figure 3B It is along Figure 3A A cross-sectional view of region X along line BB in FIG.

[0021] Figure 4 is a cross-sectional view of an overlapping first and second strap ends of a clip according to an embodiment of the present invention during a clip closing action;

[0022] Figure 5A is along Figure 4 A cross-sectional view of line AA;

[0023] Figure 5B Shows Figure 5A Two enlarged views of the upper band portion of ;

[0024] Fig. 6A is a perspective view of a connecting hook according to a second embodiment of the present invention;

[0025] Figure 6B Shows Fig. 6A A side view of a connecting hook;

[0026] Figure 6C Shows Fig. 6A A rear side view of the connecting hook;

[0027] Figure 7 is a side view of a low profile clip according to a first embodiment in a rounded and pre-assembled state; and

[0028] Figure 8 Is in a flat (not rounded) state Figure 7 Top view of the low profile clamp. DETAILED DESCRIPTION

[0029] 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 tube, hose or sheath extending substantially in the axial direction, which corresponds to the width direction of the strip material.

[0030] Figure 1 Figures 3 to 4 show a conventional low profile clip of prior art design. Figure 2 Except for the shape of the band at the end region indicated as X, the individual band elements and their functions are similar to Figures 4 to 8 The belt elements and their functions shown in the first and second embodiments of the present invention are depicted in FIG. Figure 1 Elements shown in the prior art design to FIG. 3 are marked with a prime ('), whereas elements having corresponding functions in the embodiment of the present invention do not have such a prime.

[0031] Figure 1 is a side view of the clip 10 ′ in a circular and pre-assembled state. Figure 2 The same clip 10 ′ is shown in a flat (not rounded) state having a width W, and Figure 3A and Figure 3B Shows Figure 2 A top view and a cross-sectional view of region X.

[0032] The clip 10' is made from a flat metal strip or strip 1' having a thickness t by various cutting and deformation or embossing steps generally known in the art. The tip 2A' of the first circumferential end 2' has a reduced width and forms a tongue 11' adapted to be received in a tongue channel 19' at the inside of the second end 3' of the strip 1'. In the middle of the tongue channel 19' there is a radial step 17'. The height of the step 17' corresponds to the thickness t of the flat strip material 1'. Thus, the clip 10' provides, in its closed state, a substantially step-free inner surface facing the object to be fastened.

[0033] The tongue 11' has a pre-assembled hook 12' which projects radially outwards and is suitable for Figure 1 In the pre-assembled state shown it is received in the large width portion of the tongue channel 19 ′.

[0034] Extending circumferentially from the tongue 11' in the direction towards the second end 3' of the strip 1', the clip 10' has a combined arrangement of a connecting hook or load holding hook 20' and a first tensioning hook 30'. The connecting hook 20' has a central window 22' and a free edge portion 21', which forms the radially outermost tip of the hook 20' for engagement in the hole 42' of the second tensioning hook 40'. The edge portion 21' is directed in the circumferential direction towards the second end 3', so that the edge portion 21' hooks into the hole 42' when the two strip ends 2A' and 3A' are under material deformation stress, which in the closed state of the clip 10' pulls the two strip ends 2A' and 3A' circumferentially away from each other. 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 ramp portion 23' for the outermost end 3A' of the second end 3' during the closing operation of the clip 10'.

[0035] The first tensioning hook 30' and the second tensioning hook 40' are both provided with Figure 1 The toothed protrusions 31', 41' in the circumferential direction of the clamp 10' are separated from each other. These toothed protrusions 31', 41' allow a non-slip form fit with the jaws of a pliers (not shown) engaged by the first and second tensioning hooks 30', 40' during the closing operation of the clamp 10'.

[0036] The clip 10' is also provided with a tolerance compensating element in the form of a wave 18' at the second end 3'. The curved radial shape of the tolerance compensating wave 18' allows compensating for certain diameter variations in the clip 10' and in the object to be fastened.

[0037] As in Figure 3A and 3BAs can be best seen in the enlarged view of the area X in FIG. 4 , the upper free end 3A′ may have a raised central portion that facilitates proper sliding of the free end 3A′ on the ramp portion 23′ of the connecting hook 20′ at the beginning of the closing action. However, the portion directly adjacent to the hole 42′ is not raised and has a flat surface 43′.

[0038] Such a flat surface 43' has a negative impact on the alignment of the belt during the closing stroke, in particular at its end, when the closing stresses exerted on the lower belt end 2' and the upper belt end 3' are greatest. At this stage, the upper belt portion 3' merely slides on the connecting hook 20', its flat surface 43' only coming into linear contact with the inclined surface of the ramp portion 23'. This could potentially lead to misalignment, since the flat surface 43' is inclined in the axial direction, so that it is no longer circumferentially parallel to the ramp portion 23'.

[0039] According to a first embodiment, the present invention provides a method for making the upper contact surface 45 uneven, in particular as Figure 5A and Figure 5B The circle shown solves this problem. Figure 5A and Figure 5B is a cross-sectional view taken in the axial plane. Figure 4 A cross-sectional view (taken in a radial plane) is shown during the most critical end phase of the closing stroke. In this end phase, the jaws of the pliers (not shown) act on the toothed protrusions 31, 41 of the first and second tensioning hooks 30, 40 to pull them together. Figure 4 At the stage shown, the radially inner surface 45 of the upper belt end 3 slides on the radially outer surface 25 of the topmost ramp portion 23 of the connecting hook 20 .

[0040] from Figure 5A It is best understood that any angular displacement of the relative positioning of the two contact surfaces 25, 45 in the axial direction results in a reaction force which is geometrically caused by the non-flat, in particular circular, complementary cross-sectional shape of the two contact surfaces 25, 45. This results in a centering force acting on the lower belt end 2 and the upper belt end 3, which helps to ensure self-alignment in the most critical final stage of the belt closing action.

[0041] Figure 5B Another view of the upper belt end with a non-planar contact surface 45 is shown, as well as an enlarged view of the circled portion C. The roundness is formed with a relatively large radius of curvature to benefit from the centering effect over the entire width of the contact surface 25, 45. Since the belt area axially adjacent to the second contact surface 45 is raised to the same radial height as the raised belt end 3A, the upwardly curved contact surface 45 ends axially in two lowermost edge portions 46A, 46B.

[0042] Now refer to Figures 6A-6C Explanation of the second embodiment. According to this modification, the connecting hook 20 is provided with additional guide elements 26A, 26B, which are located axially adjacent to the ramp portion 23. Such guide elements 26A, 26B are formed as radial protrusions on the left and right sides of the root portion of the ramp portion 23, so that two funnel-shaped grooves 27A, 27B are provided between the root portion of the ramp portion 23 and each of the guide elements 26A, 26B. Such funnel-shaped grooves 27A, 27B are arranged to engage with the lower edge portions 46A, 46B of the contact surface 45 at the middle stage of the closing action (i.e., the beginning of the end stage of the closing stroke when the contact surface 45 is about to slide on the root portion of the ramp portion 23).

[0043] In the following, reference will be made to Figure 7 and Figure 8 The overall clip design of the first embodiment is described. Figure 7 is a side view of the clip 10 in a circular and pre-assembled state. Figure 8 The same clip 10 is shown in a flat (unrounded) state. The width W and thickness t corresponding to the radial step 17 are Figure 1 and Figure 2 Same general design as shown in .

[0044] The general design and arrangement of the clip 10 made of a flat metal strip or strip 1 is very similar to Figure 1 and Figure 2 The overall design and arrangement of the prior art example shown in . In particular, there is a tip 2A of the first circumferential end 2, which has a reduced width and forms a tongue 11, which is suitable for being received in a tongue channel 19A at the inner side of the second end 3 of the belt 1. However, the tongue channel 19A is not formed by a cutout of the strip material as is the case with conventional channels 19'. Instead, the tongue channel 19A is closed and its "closed top" has a groove 19B for receiving the protrusion 2B at the tip 2A of the tongue portion 11. The closed design has better rigidity. In addition, a pre-assembled hook 12 is formed at the root end of the tongue 11 and is suitable for being received at Figure 7 In the pre-assembled state shown it is received in the (closed) groove 19B. Side rails 13A, 13B for preventing the belt from buckling are formed on both lateral sides of the hooks 20, 30 and the root portion of the tongue 11.

[0045] from Figure 8As can be seen in the drawing, the connecting hook 20 has a free edge portion 21 acting as an engagement tooth, which is adapted to be received in the hole 42 of the second tensioning hook 40 in the closed state of the clip 10. The connecting hook 20 also has a rear surface which has a smooth radial bevel and provides a ramp portion 23 for the outermost end 3A of the second end portion 3 during the closing operation of the clip 10.

[0046] The first and second tensioning hooks 30, 40 are both provided with toothed protrusions 31, 41 which allow a non-slip form fit with the jaws of a pliers (not shown) with which the first and second tensioning hooks 30, 40 are engaged during the closing operation of the clamp 10. Figure 1 Unlike the prior art example shown in FIG. 3 , the second tensioning hook 40 has a window 44 in the strip material 1 adjacent to the tooth-like protrusion 41 .

[0047] The clip 10 is also provided with a reduced width portion at the second end 3 in the band region between the radial step 17 and the second tensioning hook 40. This reduced width portion serves as a tolerance compensation element 18 for compensating certain diameter variations in the clip 10 and the object to be fastened.

[0048] In summary, the present invention relates to a low profile clamp 10 in which one or both contact surfaces 25, 45 of the upper circumferential end 2 and the lower circumferential end 3 have a non-flat and preferably complementary cross-sectional shape in the width direction of the strip material 1. Thus, during the strip closing action, the sliding contact of the upper contact surface 45 on the lower contact surface 25 provides a self-centering effect of the strip ends 2, 3.

[0049] Reference numerals list

[0050] 1. 1' flat strip material

[0051] 2. 2' first end

[0052] 2A, 2A' first (inner) band end

[0053] 2B protrusion

[0054] 3. 3' Second end

[0055] 3A, 3A' second (outer) band end / free end

[0056] 10, 10' clamp

[0057] 11, 11' tongue

[0058] 12, 12' pre-assembled hook

[0059] 13A, 13B side rails

[0060] 17, 17' steps

[0061] 18, 18' tolerance compensation element

[0062] 19A, 19' tongue channel

[0063] 19B groove

[0064] 20, 20' connecting hook (load holding hook)

[0065] 21, 21' edge part

[0066] 22' open window

[0067] 23, 23' slope section

[0068] 25 first contact surface

[0069] 26A, 26B guide element

[0070] 27A, 27B funnel-shaped groove

[0071] 30, 30' first tightening hook

[0072] 31, 31' first tooth-like protrusion

[0073] 40, 40' second tensioning hook

[0074] 41, 41' second tooth-like protrusion

[0075] 42, 42' hole

[0076] 43' flat surface

[0077] 44 Window

[0078] 45 second contact surface

[0079] 46A, 46B The lower edge portion of the second contact surface

[0080] WThe width of the strip material

[0081] t Thickness of the strip material

Claims

1. A clamp (10) made of a clamping band (1), the clamping band (1) having first and second circumferential ends (2, 3) overlapping each other in the 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 outwards at the first end (2), and a second tensioning hook (40) which projects radially outwardly at the second end (3) and has a hole (42) arranged to receive an edge portion (21) of the connecting hook (20) when the clip (10) is brought into a closed state by pulling the first tensioning hook (30) and the second tensioning hook (40) towards each other in a strap closing action, wherein the connecting hook (20) has a first contact surface (25) arranged for sliding contact with a second contact surface (45) during the belt closing action, the second contact surface (45) being arranged at the second end (3) circumferentially adjacent to the hole (42) of the second tensioning hook (40), Characterized in that the second contact surface (45) has a non-flat cross section in the width direction of the strip material (1).

2. The clip (10) according to claim 1, wherein: The first contact surface (25) has a non-flat cross-section.

3. The clip (10) according to claim 2, wherein: The cross section of the first contact surface (25) is formed to be complementary to the cross section of the second contact surface (45).

4. The clip (10) according to any one of the preceding claims, wherein: The second contact surface (45) has a circular shape in cross section.

5. The clip (10) according to claim 4, wherein: The cross section of the second contact surface has the shape of a ring segment.

6. The clip (10) according to claim 1, wherein: The non-flat cross section of the second contact surface (45) extends to a region immediately adjacent to the hole (42) side of the second tensioning hook (40).

7. The clip (10) according to claim 1, wherein The second end portion (3) has a radially protruding free end (3A), and The second contact surface (45) is arranged in a region circumferentially between the hole (42) of the second tensioning hook (40) and the free end (3A) of the radial projection.

8. The clip (10) according to claim 7, wherein: The area immediately adjacent to the second contact surface (45) in the width direction of the belt (1) is at the same radial height as the free end (3A) of the protrusion and extends circumferentially at this height up to the free end (3A) of the protrusion.

9. The clip (10) according to claim 1, wherein: The first contact surface (25) and the second contact surface (45) are provided only in a central portion of the clamping band (1) in the width direction.

10. The clip (10) according to claim 1, wherein: The connecting hook (20) has a central ramp portion (23) having the first contact surface (25) at a radially outer portion thereof.

11. The clip according to claim 10, wherein: The connecting hook has one or more guide elements (26A, 26B) adjacent to the central ramp portion (23) in the width direction, and the one or more guide elements (26A, 26B) are used to center the second end portion (3) during the closing action.

12. The clip (10) according to claim 11, wherein: The one or more guiding elements (26A, 26B) provide one or more funnel-shaped grooves (27A, 27B) between the root of the ramp portion (23) and the guiding elements (26A, 26B), and the one or more funnel-shaped grooves (27A, 27B) are arranged to engage with one or more lower edge portions (46A, 46B) of the second contact surface (45) during the mid-stage of the closing action.

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