Rivet-like connection for overlapping band portions

Abstract: A rivet-like connection for mutually overlapping band portions comprises two tab-like members 13a , 13b spaced in the transverse direction of the band and bent up from the underlying band portion the about axes extending in the longitudinal direction of the band. A cold-deformed, deep-drawn support hook 12 extends upwardly from the underlying band portion. Apertures 14 , 15 are provided in the overlying band portion for engagement by the tab-like members 13a , 13b and the support hook 12 . The tab-like members 13a , 13b have a height when bent up which is sufficiently greater than the thickness of the overlying band portion. The tab-like members 13a , 13b being bent over the outer surface of the overlying band portion to hold it down onto the underlying band portion.

Description: Field of the Invention This invention relates to a rivet-like connection for overlapping band portions, specifically of a clamp structure with a lever-type closure mechanism for tightening the clamp. Background of the Invention Clamp structures with lever-type closure mechanisms are known in the art. For example, a simple toggle-link in a clamp structure is shown in US-A-2,440,260. Another type of lever-actuated closure mechanism for a hose clamp is shown in FR-A-1,116,743. Commercially successful lever-type hose clamps are shown and described in US-A-3,475,793, the contents of which are incorporated by reference in this application. Though the lever-type clamp structures in US-A-3,475,793 disclosed the use of tensional spring elements in the form of lugs or folds, these folds or lugs left an opening underneath the same which had to be bridged by a separate bridging element to avoid the possibility of leakage within that area. This, in turn, increased the cost of manufacture by the need for separate parts in the form of bridging or connecting members which had to be installed manually. Economic reasons therefore normally prompted the omission of such tensional spring elements in the commercial versions of these lever-type clamp structures. Summary of the Invention It is therefore a principal object of the present invention to provide a rivet-like connection for overlapping band portions, specifically of a clamp structure with a lever-type closure mechanism for tightening the clamp, which avoids by simple means the shortcomings and drawbacks of the prior art, and which can be manufactured and assembled in a cost-efficient manner. This object is met by the invention defined in claim 1, preferred embodiments being set forth in the dependent claims. Brief Description of the Drawings These and other objects, features and advantages of this invention will become more apparent from the following description, when taken in conjunction with the accompanying drawing which shows, for purposes of illustration only, an embodiment of the invention, and wherein: Figure 1 is a somewhat schematic axial elevational view of a lever-type clamp structure; Figure 2 is a plan view on the clamping band used in the clamp structure of Figure 1; Figure 3 is a side elevational view of the clamping band of Figure 2; Figure 4 is partial top plan view on the lever-type closure mechanism in the closed position thereof, taken along line 4-4 of Figure 1; Figure 5 is a partial top plan view of the rivet-like connection obtained with a clamping band end section in accordance with this invention; and Figure 6 is a partial cross sectional view taken along line 6-6 of Figure 5. Detailed Description of an Embodiment Referring now to the drawings, reference numeral 10 generally designates a lever-type clamp structure which includes a clamping band 11 that is connected with the lever-type closure mechanism generally designated by reference numeral 20 . The clamping band 11 which in this embodiment is made integral, in one piece, includes in its end portion 11a' two tab-like members 13a , 13b obtained by two mutually oppositely directed substantially U-shaped cuts and bent up about axes extending in the clamping band longitudinal direction so that the tab-like members 13a , 13b extend substantially parallel to one another in the centre area of the clamping band. The two tab-like members 13a , 13b are followed by one cold-deformed, deep-drawn support hook 12 which may be realised by a more or less transversely extending cut in the clamping band and subsequent pressing out by deep-drawing to provide an engaging surface 12' , as more fully described in US-A-4,299,012. Spaced from the support hook 12 in a direction away from the free end of the band end portion 11a are two apertures 14 and 15 , with the support hook 12 being adapted to engage in aperture 14 and the two tab-like members 13a , 13b in aperture 15 once the band end portion 11a' is bent back upon itself about the cross web 27 after being extending through slot 21' provided in the base portion 21 of the relatively fixed part of the closure mechanism 20 , and leaving again through slot 21' to form the underlying band end portion 11a' of the band end section 11a . The end section 11a of the clamping band 11 is preferably fixedly secured to the relatively movable lever part 25 of the closure mechanism 20 which can be readily achieved with the use of an impact tool bending the two tab-like members 13a , 13b outwardly into the plane of the clamping band as shown in greater detail in Figure 6, With the use of an appropriately shaped impact tool, a rivet-like connection can be realised with a single impact in a very simple manner. The other clamping band end section 11b is provided with a predetermined number of undulations 17 which are covered from below by the remaining band end portion 11b' after the clamping band end section 11b is extended through the slot 21" provided in the base portion 21 of the relatively fixed part of the closure mechanism 20 and then bent back upon itself as shown in Figure 1 to form the underlying band end portion 11b' . In addition to the base portion 21 provided with the two slots 21' and 21" , the relatively fixed part of the closure mechanism 20 includes two side portions 22a and 22b integral with the base portion 21 and extending at substantially right angle to the base portion 21 . The relatively fixed frame part 21 , 22a , 22b of the closure mechanism 20 is made from sheet metal of appropriate thickness and its side portions 22a , 22b are spaced from each other a distance sufficient to accommodate the pivotal movement of the lever member generally designated by reference numeral 25 which itself is provided with an elongated U-shaped opening 28 open at the inner end thereof and interrupted about one-half to about two-thirds of its length from the open end by the cross web 27 integral with the leg portions 25a and 25b defining the opening 28 . The lower end area of the toggle-type lever member 25 is provided along the leg portions 25a and 25b with mutually oppositely and outwardly directed pin-like pivot members 26a and 26b adapted to engage in corresponding aligned pivot holes 29a and 29b provided in the side portions 22a and 22b . To reduce the risk of inadvertent opening of the closure mechanism from its tightening position illustrated in Figure 1, two inwardly directed, mutually facing projections 24a and 24b are provided on the inside of the side portions 22a and 22b . Their location in the right hand comer area, as viewed in Figure 1, i.e., in the comer area which is traversed by the lever member during its movement from the open position, in which the lever 25 is approximately in the 11 o'clock position, into the closed or tightening position shown in Figure 1, is of some importance because in that location, the projections 24a and 24b can be made longer due to the greater flexibility of the side portions 22a and 22b the farther these projections are away from the base portion 21 . The lever member 25 consists of a generally curved portion 25' with a radius of curvature sufficiently large so that the lever member 25 can move freely into its tightening position without interference by the undulations 17 and terminates in a rectilinear end portion 25" which extends outwardly when the lever member 25 is in the tightening position to facilitate re-opening of the closure mechanism. The lever portions 25' and 25" are so shaped and arranged that in the tightening position, as shown in Figure 1, the lower surface of the lever member 25 within the area of transition from the curved portion 25' to the rectilinear portion 25" almost contacts the outer surface of the clamping band end section 11b . The leg portions 25a and 25b defining the elongated U-shaped opening 28 are spaced at such a distance from one another that the clamping band 11 can extend therethrough. As to the rest, the closure mechanism is of a construction as more fully disclosed in US-A-3,475,793 and therefore will not be described in further detail. The clamping band 11 is made in one piece and can be chosen to suit the needs of the particular application. By selecting a thicker and therewith stronger clamping band material, the clamp structure is also particularly suitable for heavy-duty applications. A typical example of a suitable clamping band is as follows. For a clamp structure with a theoretical clamping range of about 77.5 mm to about 81.5 mm in diameter, the clamping band is made of galvanised steel having a width of 10 mm and thickness of 0.5 mm. The overall length of the clamping band is 332.2 mm, the length of the tab-like members 13a , 13b in the longitudinal direction of the clamping band is 3 mm and the distance a is 8mm. The length of the cold-deformed support hook 12 in the longitudinal direction is 2.8 mm and the distance b is 13.3 mm, while the apertures 14 and 15 are 3.5 mm in width and 3.3 mm in length. The distance c is 74.5 mm and the distance d is 5.5 mm. The maximum height of the support hook 12 is about 1.8 mm from the bottom surface of the clamping band to the top surface of the support hook, and the height of the tab-like members 13a , 13b from the bottom surface of the clamping band to the top of the bent-up tab-like members is about 2.4 mm. The width of the support hook is about 3.3 mm, and the mutually facing surfaces of the tab-like members are spaced 1.8mm. The three undulations 17 extend over a length of about 14.1 mm with a maximum depth from the plane of the clamping band in one direction only of about 2.85 mm from the top surface of the clamping band to the peak bottom surface of the undulation. The start of the undulations is spaced about 41.9 mm from the corresponding end of the clamping band (distance e). For ease of assembly, it may also be desirable to pre-bend the clamping band for installation in the closure mechanism 20 . The rivet-like connection shown in detail in Figures 5 and 6 offers several advantages over the riveted connection disclosed in US-A-3,286,314. On the one hand, it offers a symmetrical stress distribution in the clamping band within the area of the tab-like members 13a , 13b leaving equal amounts of damping band material on both outer sides of the tab-like members as well as a predetermined amount of clamping band material in the centre area of the clamping band between the two tab-like members as contrasted with the asymmetric arrangement in US-A-3,286,314 in which the tab-like member as well as the slot receiving the tab-like member are located to one side of the clamping band. Additionally, the presence of the cold-deformed support hook 12 assists in absorbing large tensional forces which may occur in the clamping band longitudinal direction, thereby obviating the need for the large impact forces required in the US-A-3,286,314 to achieve the rivet deformation not only of the tab-like member but also of the underlying band portion. On the other hand, the holding ability of the connection illustrated Figures 5 and 6 is quite remarkable because tensional forces in the clamping band are absorbed by two symmetrically arranged tab-like members in conjunction with the absorption capability of the support hook which minimises the likelihood of failure of the clamping band as a result of tearing. US-A-4,622,720 discloses a connection utilising two cold-deformed support hooks which come into operation after the two overlapping band portions are moved toward one another by a combined tab-like guide and support hook provided for that purpose with an inclined guide surface. Once the overlapping band portions are moved close to one another and the support hooks have become operative, the tensional forces in the clamping band are absorbed principally by the support hooks with the combined guide and support hook playing an assisting role. However, in the arrangement according to Figure 5 of this application, the two tab-like members 13a , 13b continue to play a significant role at all times in absorbing the tensional forces in the clamping band whereby the bent-over tab-like members also assure immediate cooperation between the engaging surface of the support hook 12 and the corresponding edge of aperture 14 because the outer clamping band portion is held down onto the inner band portion once the tab-like members are bent over. The connection illustrated in Figure 5 has therefore universal applicability where such a pre-assembly of overlapping band portions is desired, for example, in screw-type clamps of the type disclosed in US-A-4,521,940.

Claims: A rivet-like connection for mutually overlapping band portions, comprising two tab-like members ( 13a , 13b ) spaced in the transverse direction of the band and bent up from the underlying band portion said about axes extending in the longitudinal direction of the band, a cold-deformed, deep-drawn support hook ( 12 ) extending upwardly from the underlying band portion, and aperture means ( 14, 15 ) in the overlying band portion for engagement by said tab-like members ( 13a, 13b ) and said support hook ( 12 ), said tab-like members ( 13a, 13b ) having a height when bent up which is sufficiently greater than the thickness of the overlying band portion, said tab-like members ( 13a, 13b ) being bent over the outer surface of the overlying band portion to hold it down onto the underlying band portion. The rivet-like connection of claim 1, wherein said two tab-like members ( 13a, 13b ) are disposed nearer the free end of the underlying band portion than the support hook ( 12 ), and the aperture means ( 14, 15 ) are in the form of two rectangular apertures. The rivet-like connection of claim 1 or 2, wherein said two tab-like members ( 13a, 13b ) are punched out of said underlying band portion substantially symmetrically with respect to the longitudinal centre axis of the band. The rivet-like connection of any preceding claim, wherein said tab-like members ( 13a, 13b ) are formed by oppositely directed, substantially U-shaped cuts in such a manner that the bending axes for the tab-like members ( 13a , 13b ) are located near the longitudinal sides of the underlying band portion and are bent over said overlying band portion in mutually opposite directions toward the sides of the band. The rivet-like connection of any preceding claim, wherein said overlapping band portions constitute a damping band end portion ( 11a ) bent back upon itself to receive a web ( 27 ) of a lever ( 25 ) as part of a closure mechanism for tightening a clamp.

Inventors: OETIKER HANS, OETIKER, HANS
Applicants: OETIKER HANS MASCHINEN, HANS OETIKER AG MASCHINEN- UND APPARATEFABRIK
Application year: 1996
Main classification: F16L33
IPC codes: B65D63, F16L33