MECHANICAL CONNECTION FOR OPEN-TYPE HOSE CLAMPS

FIELD OF THE INVENTION

The present invention relates to an open-type hose clamp with a mechanical connection interconnecting overlapping band portions which includes a guide hook extending outwardly from the inner band portion and adapted to engage in a corresponding aperture in the outer band portion.

BACKGROUND OF THE INVENTION

Open-type hose clamps are known in the prior art which include one or more hook members extending outwardly from the inner band portion and adapted to engage in corresponding apertures in the outer band portion.

These prior art mechanical connections for open-type hose clamps usually include a rectangularly shaped hook member extending outwardly from the inner band portion into a rectangularly shaped aperture provided in the outer band portion as shown, for example, in U.S. Patent 3,321,811 to Thomas. The hook members described above are usually bent out of the band material through an angle less than 90° to act as "guide" members by causing the overlapping band portion to be drawn inwardly toward the inner band portion during tightening of the clamp. Reopening of the mechanical connection of the clamp is likely when such guide members are bent to a 90° position and therebeyond during tightening of the clamp.

The apertures in the outer band portion are thereby relatively long to permit movement of the guide hook members in the circumferential direction of the clamp and are much greater than the thickness of the clamping band material which normally consists of galvanized steel or stainless steel band material.

Owing to the limited resistance of these hook members causing them to bend back during the tightening of the clamp, there always exists then the resulting danger of unwanted reopening

of these open-type hose clamps during the installation of the clamp over the object to be fastened thereby.

There are two usual methods of installing these open-type hose clamps, that is, axially and radially over the object to be fastened thereby. To be able to install these open-type clamps axially, the mechanical connection interconnecting the overlapping band portions must stay closed, i.e., the hook member (s) constituting the mechanical connection must stay engaged in the aperture (s) of the mechanical connection. However, there is always the problem of inadvertent reopening as a result of bending back of the hook member (s), especially also during such axial installation because the clamps are made from flat steel band material and are normally predeformed into more-or-less circular shape, thereby leaving a residual stress in the thus predeformed band material which seeks to return to the prior flat shape. The prior art mechanical connections as used heretofore with the use of at least one of such guide hooks of the type described above provides no assurance against reopening . When installing the clamp radially over the object to be fastened thereby, it is again necessary that the mechanical connection remain engaged during the entire tightening operation of the clamp. The prior art mechanical connections of the type described above do not provide the necessary assurance to remain engaged.

It is therefore an object of the present invention to provide a mechanical connection in the overlapping band portions of so-called open-type hose clamps which assures that the mechanical connection remains engaged from initial installation throughout the entire tightening operation of the clamp.

Another object of the present invention resides in a mechanical connection for open-type hose clamps which is simple, easy to manufacture and reliable in operation.

SUMMARY OF THE INVENTION The present invention solves the aforementioned problems encountered with the mechanical connections described above by modifying both the guide hook member as also the aperture into which the hook member engages. More particularly, the aperture no longer consists of a simple rectangular aperture but, according to this invention, includes a substantially rectangular portion of greater width and limited length and a longer portion of reduced width connected with the wider portion by way of converging portions. In turn, the hook member is provided with cutouts of substantially rectangular shape extending inwardly from both lateral surfaces which are of such width and depth that the hook member can slide into the longer aperture portion of reduced width and at the same time positively locks the mechanical connection.

BRIEF DESCRIPTION OF THE DRAWINGS These and other objects, features and advantages of the present invention will become more apparent from the following description when taken in connection with the accompanying drawing which shows, for purposes of illustration only, one embodiment in accordance with the present invention, and wherein:

Figure 1 is a perspective view on an enlarged scale of a prior art open-type hose clamp as disclosed in U.S. Patent 4,299,012 whose prior art mechanical connection as shown in Figures 2 and 3 of this patent only needs to be modified in accordance with the present invention as shown in Figures 5-7 herein;

Figure 2 is a partial, somewhat schematic plan view on an enlarged scale on the inner band portion of a prior art

mechanical connection provided with a rectangular guide hook for the mechanical connection of the clamp;

Figure 3 is a somewhat schematic partial plan view on an enlarged scale on the outer band portion of a prior art mechanical connection provided with a rectangular aperture for the guide hook;

Figure 4 is a somewhat schematic cross-sectional view taken along line IV-IV of Figure 2;

Figure 5 is a somewhat schematic partial plan view, on an enlarged scale, similar to Figure 2, on the guide member of the mechanical connection provided in the inner band portion in accordance with the present invention;

Figure 6 is a somewhat schematic partial plan view, on an enlarged scale similar to Figure 3, and illustrating the aperture for the guide hook in the mechanical connection according to the present invention; and

Figure 7 is a somewhat schematic elevational view on an enlarged scale of the guide hook in accordance with the present invention. DETAILED DESCRIPTION OF THE DRAWINGS

Referring now to the drawing, wherein like reference numerals are used throughout the various views to designate like parts, the prior art clamp of Figure 1, as described in U.S. Patent 4,299,012 includes a clamping band 11 with overlapping band portions 11a and lib and with a plastically deformable ear generally designated by reference numeral 13 and known in the trade as "Oetiker" ear after the name of its inventor. The "Oetiker" ear is of generally hat-shaped configuration formed by leg members 14 and 15 interconnected by a bridging portion 16 that preferably includes a reinforcing means 17. To assure an internal clamping surface devoid of steps, gaps and discontinuities, especially at the end of the inner band portion lib, the prior art clamp further includes a

means to avoid such steps and discontinuities that includes a tongue-like extension 61 at the end of the inner band portion lib adapted to extend through an opening provided in the step- like portion 67, all as more fully described in the 4,299,012 Patent. The mechanical connection of this prior art clamp, illustrated also in Figures 2-4 of this application, includes a rectangularly shaped guide hook member 31 extending outwardly from the inner band portion lib and adapted to engage in a rectangular aperture 35 in the outer band portion 11a as more fully shown also in Figure 4 of this patent.

The prior art guide hook member 31 is thereby obtained by a cut in the clamping band material of the inner band portion lib involving three sides of a rectangle as shown in Figures 2 and 3 herein to be bent outwardly about the axis x-x also shown in Figure 2 herein through an angle less than 90°.

As the hook member 31 is extended through the aperture 35, the angle α of less than 90° normally prevents the outer band portion lla from escaping outwardly owing to the residual stress which is left in the clamping band as a result of the predeformation into approximately circular shape. In other words, the outer clamping band portion lla has an inherent tendency to return to its prior flat shape which would cause the mechanical connection to reopen in the absence of the particular position of the guide hook member 31 bent out through an angle less than 90°.

BRIEF DESCRIPTION OF THE INVENTION

According to the present invention, as illustrated in Figures 5-7 of this application, in which similar reference numerals of the 100 series are used, this is prevented in a simple, reliable manner by changing the prior art rectangular aperture 35 of Figure 3 into a modified aperture generally designated by reference numeral 135 (Fig.6) of more complex

shape. The guide hook member generally designated by reference numeral 131 (Figures 5 and 7) is now also modified accordingly as will be described more fully hereinafter.

More specifically, the aperture 135 includes an aperture part 121 of a length Ii width di somewhat greater than the length and width of the hook member 131 to permit easy insertion thereof into the aperture part 121. The more or less rectangular aperture part 121 is adjoined by an aperture part 122 that gradually narrows in the longitudinal direction and is formed by converging surfaces 122a and 122b terminating in a relatively narrower and longer aperture part 123 of diameter d ₂ and extending in the longitudinal direction of the clamping band. The aperture parts 121 and 123 are preferably of substantially rectangular shape while the converging portions 122a and 122b may be continuously curved or be linear preferably passing over into the aperture portions 121 and 123 by rounded-off curvatures of relatively small radius. The angle of convergence can be suitably chosen depending on the type and width of the band material, on the width of the hook member 131 which in turn depends to some extent on the width of the clamping band material. The converging surfaces 122a and 122b may thereby form an angle with the longitudinal direction of the clamping band material from about 55° to about 35°, preferably 50 to 40°. The length of the converging portions 122a and 122b as also all other dimensions of the hook member 131 and of the aperture 135may also be empirically determined for optimal condition depending on the length of the aperture portion 123 which in turn depends on the width of the guide member 130 and the material used for the clamping band.

To achieve the lock-up condition of the mechanical connection, the guide member 130 is provided with two substantially • rectangular cut-outs 132a and 132b in the area adjoining the axis x-x about which the guide member is bent out of the clamping band material, i.e., within the area to the left of the axis x-x of Figure 2. The height h of the cut-outs 132a and 132b is thereby somewhat larger than the thickness of the clamping band material sufficient to permit easy sliding movement of the guide hook member 131 in the area of the aperture portion 123. The depth d of the cut-outs 132a and 132b must be correlated to the width d ₂ of the aperture part 123. In each case, the depth d of these cut-outs 132a and 132b must be such that the remaining part 131a left in the hook member 131 is slightly smaller than the width d ₂ of the aperture part 123 so that the guide member 130 can readily slide from the aperture part 121 into the aperture part 123. The depth d of the rectangular cut-outs 132a and 132b is such that the remaining reduced width portion 131a of the hook member 130 is not weakened excessively while the width of the cut-outs 132a and 132b must be sufficiently greater than the thickness of the clamping band material to allow free sliding movement of the hook member through the aperture part 123. Again, optimum dimensions can be readily determined empirically depending on type and size of the clamping band material. Typical values for the d depth of the cut-outs 132a and 132b are such that the width of the reduced width portion 131a is at least about 50% of the normal width of the hook member, preferably from about 50% to about 70%. The height h of the cutouts is preferably at least 1.15 times the thickness of the clamping band material.

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O P E RA T I O N

The engagement of the mechanical connection in accordance with the present invention is quite simple and does not depart materially from what was done heretofore. All that is necessary is to engage the hook member 130 through the aperture portion 121 whereupon the residual stress in the clamp seeking to enlarge its diametric dimension is likely to normally cause the guide member 130 to slide toward the aperture portion 123. If necessary, this can be assisted by a slight pressure on the guide member 130 in this direction. Once the guide member 130 leaves the aperture portion 121 and reaches the aperture portion 123, the mechanical connection remains securely locked against reopening by engagement of the sides of the aperture portions 122a, 122b, 123 engaging in cutouts 132a and 132b. With clamps equipped with a plastically deformable, so- called "Oetiker" ear which is plastically deformed for tightening the clamp, the guide member 130 will move during contraction of the "Oetiker" ear until it reaches the end of the aperture portion 123 and will stay in such position during the remaining tightening and after completion of the tightening of the clamp.

The present invention thus assures a lock-up of the mechanical connection by extremely simple means that require no major changes in the manufacture of the clamp from clamping band material as only some cutting dies have to be changed.

While I have shown and described only one embodiment in accordance with the present invention, it is understood that the present invention is not limited to the embodiment illustrated but is equally applicable to all other types of open-type clamps which utilize a mechanical connection with a guide hook member of the type described above.

Additionally, it is also understood that the shape of the aperture 120 may be changed at will to suit particular needs by

changing the length of the aperture parts 121 and 123 as also the effective length formed by the converging parts 122a and 122b and by changing the angle α.

The present invention is also applicable to mechanical connections in which the members extend inwardly from the outer band portion into apertures provided in the inner band portion.

The present invention is thus not limited to the embodiment illustrated but is applicable to other mechanical connections and may be varied to suit any particular need, and I therefore do not wish to be limited to the illustrated embodiment, but intend to cover all such changes and modifications as are encompassed by the scope of the appended claims .