WO2006111181A1

WO2006111181A1 - An arrangement for connecting the ends of an open clamp

Info

Publication number: WO2006111181A1
Application number: PCT/EP2005/004253
Authority: WO
Inventors: Eric Kenwright
Original assignee: Hans Oetiker Ag Maschinen- Und Apparatefabrik
Priority date: 2005-04-20
Filing date: 2005-04-20
Publication date: 2006-10-26

Abstract

For connecting the mutually overlapping band end portions A, B of an open clamp, a window (10) is provided in a first end portion (A) for engagement by a hook (20) provided on the second end portion (B). The hook (20) is pressed from the band material, starting at an opening (21) punched from the band material of the clamp. The opening (21) is formed by two substantially circular holes (22) and a parallelsided cut-out (23) connecting the hole (22), the width of the cut-out (23) as measured in the longitudinal band direction being smaller than the diameter of the holes (22).

Description

An Arrangement for Connecting the Ends of an Open Clamp

Description

Prior Art

US 4,622,720 discloses an open hose clamp made of band material in which the outer one of the two mutually overlapping end portions is provided with windows for engagement by hooks provided on the inner band end portion. This clamp has the features included in the first part of claim 1. The hooks are produced by forming in the band material a cut extending transversely of the longitudinal direction of the band, and pressing the adjacent band material out of the band by cold deformation. In addition to these pressed hooks, the known band clamp has a guide hook which consists of a tab bent out of the material of the inner band end portion for engagement with a longitudinal cut provided in the outer band end portion. The edge of the tab remote from the inner band end is undercut to prevent inadvertent opening of the clamp.

EP 0 672 858 A1 shows a further open clamp made of band material wherein a window is formed in the outer band end portion to receive an embossment formed at the inner band end portion. The edge of the window remote from the outer band end has a lug projecting into the window, which lug, in the closed condition of the clamp, engages in a slot provided at the embossment to secure the clamp against inadvertent opening.

Summary of the Invention

It is an object of the invention to improve the connection of the end portions of an open clamp, and more specifically to form the connection so that it withstands high tensional force.

This object is met by the invention characterised in claim 1. The hook formed in accordance with claim 1 starts at an opening in the band material, the opening constituting an edge for engagement with the window with an undercut which causes the central part of the hook to extend above and beyond the corresponding edge of the window. The opening also avoids the considerable stress which in conventional pressing or deep drawing deformation occurs in this area of the hook and tends to result in cracks.

The features of claims 2 and 3 are advantageous in that they assist in reducing stress on the hook. The embodiment recited in claim 4 is useful to ensure safe engagement between the hook and the edge of the window, at the same time avoiding unnecessary outward projecting parts of the clamp.

The development of the invention according to claims 5 and 6 further serves to increase the safety of the engagement between hook and window. The feature of claim 6 is advantageous for achieving easy tightening of the clamp because the lug, due to its oblique disposition, tends to move under the hook.

In the embodiment of claim 7, the outline of the window substantially follows the shape of the hook whereby any weakening of the material by an unnecessarily large window size and stress concentration are avoided.

The further embodiment of the invention according to claim 8 is of advantage in that it further makes the clamp easy to install.

Claims 9 to 1 1 relate to an advantageous process of manufacturing the connection arrangement according to the invention, wherein the hook is formed by means of a progressive die method in which the opening is formed in a first punching step for producing the engaging edge of the hook, and the hook shape proper is produced in a subsequent pressing or deep-drawing step.

Brief Description of the Drawing

An embodiment of the invention will be explained in more detail below with reference to the drawing in which

Fig. 1 shows the two end portions of a clamp made of band material in a flat condition,

Fig. 2 is an enlarged representation of the band end portions with punched portions forming the window and the hook, Fig. 3 shows the band end portions of Fig. 2 after deformation by pressing,

Fig. 4 is a side view of the band end portions, and

Fig. 5 is a section through the two band end portions in the hooked condition.

Detailed Description of an Embodiment The clamp shown in a flat condition in Fig. 1 has in its first, left-hand band end portion A two identically shaped windows 10, and in its second, right-hand band end portion B two identically shaped hooks 20 and a tightening ear 30 the bridge portion of which has a reinforcing depression 31. The tightening ear 30 is a so-called Oetiker ear of the type provided also in the hose clamp known from US 4,622,720 referred to above. One of the two windows 10 is shown in the left-hand part of Fig. 2 on an enlarged scale. The window 10 has two edges 11 extending parallel to the longitudinal band edges 32. The ends of the edges 11 remote from the first band end 12 are joined by a semicircular edge 13. A lug 14 projecting into the window 10 is formed at the edge of the window 10 remote from the first band end 12. The lug 14 has a width corresponding to 1/4 to 1/3 of the width of the window 10. The lug 14 is confined by a semicircular convex edge which is connected to the lateral edges 11 of the window 10 by semicircular concave edges 15.

The right-hand part of Fig. 2 shows an opening 21 punched out of the band material, the opening 21 being formed by two circular holes 22 and a parallel- sided cut-out 23 which interconnects the holes 22 and extends transversely of the longitudinal band direction. The width of the cut-out 23 as measured in the longitudinal direction of the band is about 1/3 to 1/2 the diameter of each hole 22. The rectilinear edge 25 of the cut-out 23 remote from the second band end 24 merges tangentially into the inner edges of the holes 22.

Fig. 2 shows the band end portions A and B subsequent to a punching step.

Fig. 3 shows the band end portions A and B after a subsequent pressing or deep drawing step. In this step, the lug 14 formed within the window 10 is bent down obliquely while the portion of the material adjoining the opening 21 in the direction toward the second band end 24 is pressed upward to form a roof-like structure which rises obliquely in a direction away from the second band end 24, thereby constituting the hook 20. During this pressing step, the central upper part 26 of the hook 20 is pressed parallel to the surface of the band material. The right-hand part of Fig. 4 is a side view of the hook thus formed. As shown, the circular holes 22 form undercuts 27 in the finished hook 20.

In the engaged condition shown in Fig. 5, the second band end portion B extends above and beyond the first band end portion A, with the hooks 20 engaging the windows 10. In course of engagement, the bent-down lugs 14 projecting into the windows 10 move underneath the central parts 26 of the hooks 20 while the convex edges 15 of the windows 10 abut the undercuts 27 of the hooks 20. An intimate connection between the hook 20 and the corresponding window 10 is thus achieved and inadvertent opening of the connection is prevented.

Claims

1. An arrangement for connecting the mutually overlapping end portions (A₁ B) of an open clamp made of band material, including a window (10) provided in a first end portion (A) and a hook (20) formed in a second end portion (B) for engaging the window (10), the hook (20) being deep-drawn from the band material starting at a cut in the band material, characterised in that the cut defines a punched opening (21) which has a greater width in the longitudinal direction of the band at its end portions (22) adjacent the longitudinal band edges than in its central portion (23).

2. The arrangement of claim 1 , wherein the opening (21) is formed by two substantially circular holes (22) and a parallel-sided cut-out (23) interconnecting the holes, the width of the cut-out (23) in the longitudinal direction of the band being smaller than the diameter of the holes (22).

3. The arrangement of claim 2, wherein the edge (25) of the opening (21) remote from the second band end (24) extends tangential Iy with respect to the edges of the holes (22).

4. The arrangement of any preceding claim, wherein the free end of the hook (20) has a flat central part (26) as viewed transversely of the longitudinal band direction such that the central part (26) is inclined with respect to the surface of the band at a smaller angle than the rising part of the hook (20).

5. The arrangement of any preceding claim, wherein a lug (14) projecting into the window (10) is formed at the edge of the window (10) adjacent the first band end (12).

6. The arrangement of claim 5, wherein the lug (14) is bent out of the band material in a direction opposite to the deep-drawing direction of the hook (20).

7. The arrangement of claim 5 or 6, wherein the edge (13) of the window (10) remote from the first band end (12) has a substantially semicircular shape.

8. A clamp having a connecting arrangement according to any preceding claim, the clamp being pre-bent such that the first band end portion (A) provided with the window (10), in the closed condition of the clamp, overlaps the outer side of the second band end portion (B) carrying the hook (20).

9. A method of producing an arrangement for connecting the mutually overlapping end portions (A, B) of an open clamp made of band material, wherein a window (10) is punched out of a first end portion (A) and a hook (20) for engagement in the window (10) is punched out of a second end portion (B), characterised in that the hook (20) is formed by punching an opening (21) out of the band material in a first step, the opening (21) having a greater width in the longitudinal direction of the band at its end portions adjacent the longitudinal band edges than in its central portion, and pressing a portion contiguous with the opening (21) out of the band material in a second step.

10. The method of claim 9, wherein the window (10) is punched out of the band material simultaneously with the opening (21).

11. The method of claim 10, wherein a lug (14) projecting into the window (10) is formed at the edge of the window (10) adjacent the first band end (12), the lug (14) being bent out of the band material in said second step in a direction opposite to the pressing direction of the hook (20).