High strength clamp structure

Abstract: A hose clamp (10) with an ear-like structure (12) is adapted to be selectively strengthened to achieve desired holding ability and/or re-tightening forces, as needed. This is achieved by complementary ear-like structures (12a,12b) in the overlapping inner and outer band portions (11a,11b) with the free ends of the inner and outer band portions connected with the corresponding overlapping, respectively, overlapped band portion. In addition or in the alternative, the ear-like structure (12) is strengthened by external and/or internal strengthening members (135) made of spring steel with predetermined spring characteristics.

Description: FIELD OF INVENTION The present invention relates to hose clamps with an ear-like structure strengthened to increase the holding ability thereof, and more particularly to ear-like structures internally and/or externally strengthened by the use of one or more strengthening members which have the shape more or less complementary to the ear-like structure. BACKGROUND OF THE INVENTION Various attempts have been made heretofore to strengthen ear-like structures of clamps, especially hose clamps, in order to increase their holding ability and/or their spring properties which determine the elastic re-tightening forces in case of expansion of the hose clamp due to temperature and/or pressure increases. For example, narrow reinforcing grooves of more or less canoe shape as viewed in plan view have been proposed in my prior U.S. Patent 3,475,793 for the bridging portion of so-called "Oetiker" ears. My prior U.S. Patent 3,510,918 proposed the use of an elastic insert member to control the elastic properties of the ear. A plug made from rod-shaped elastic material or hollow spring steel was also proposed in my prior U.S. Patent 3,579,754. Considerable improvements for increasing the holding ability of ear-like structures were attained with a reinforcing depression provided in the bridging portion of the ear-like structure, as more fully disclosed in my copending application Serial No. 06/922,408, the subject-matter of which has been published in my corresponding British Patent 2,160,577. According to this application, the reinforcing depression is a relatively shallow, generally pan-shaped depression of generally rectangular shape as seen in plan view with the sides extending over substantial portions of the width and length of the bridging portion in its non-reinforced condition. Though the various ways of increasing the holding ability of ear-like structures and/or controlling the elasticity thereof, as proposed heretofore by me, have proved very successful, the advent of new hose materials and/or applications to ever-greater ranges of temperature and/or pressure changes demand ever-improved characteristics in hose clamps. Proposals have also been made heretofore by others to address these and other problems. For example, the U.S. Patent 3,087,221 proposed a hose clamp which had its greatest radial band thickness near the middle with the thickness progressively reduced towards the ends for the avowed purpose to maintain a true circle initially and upon change of diameter. In Figure 3 of this patent, the ear itself was also proposed to be made in the same manner as the clamping band, i.e., having its greatest thickness in the middle with reduced thickness toward the ends of the ear. Apart from a lack of disclosure of how the clamps as proposed in this patent could be realized in practice, this patent was concerned only with maintaining a true circular configuration of the parts in question. The European Patent 0 208 598 discloses an arrangement for a clamp structure provided with an outwardly extending circular fold or loop in the clamping band in which the elasticity reserve is to be determined by a slotted sleeve surrounding the fold or loop. According to this patent, the outwardly extending fold or loop is to limit the elasticity reserve in a fold or loop of the type shown in Figure 1 in my prior U.S. Patent 3,475,793 in which bent-out lugs or folds constitute tensional spring elements. Another approach to affecting the holding ability of a so-called "Oetiker" ear can be found in my prior Swiss Patent 580,247 in which the plastically deformed ear can be subjected only to a predetermined maximum reopening force. However, the force for reopening the ear up to its maximum limit is unaffected by this arrangement. The more recently issued U.S. Patent 4,430,775 proposed a banding strap according to the preamble of claim 1, for attaching a heat shield to a muffler in which the overlapping band portions were provided with outwardly projecting folds so constructed and arranged that the fold in the inner band is received in the bite of the fold in the outer band. The inner and outer bands are held in position by a "snap-in" feature preventing the folds from springing apart before they can be crimped together. Furthermore, lateral misalignment is intended to be prevented by dimples which also add material strength and stiffness to the central sections of the folds. However, tests have indicated that the nesting arrangement of the folds as disclosed in this patent will not, as such, materially strengthen the fold's holding ability over that in a hose clamp with a similar fold but constituted only in the outer band portion, i.e., by a single band layer. SUMMARY OF THE INVENTION It is a principal object of the present invention to provide an ear-like structure in hose clamps which offers greatly improved holding characteristics. Another object of the present invention resides in a hose clamp with an ear-like structure in which not only the holding ability but also the re-tightening spring characteristics can be accurately controlled in accordance with the requirements of a given situation. A further object of the present invention resides in an ear-like structure for hose clamps which can be selectively modified as to its strength and spring characteristics by extraordinarily simple means. Still another object of the present invention resides in a hose clamp with an ear-like structure whose holding strength and re-tightening capabilities can be vastly increased so as to enable use with hoses subject to large breathing due to internal temperature and/or pressure changes. These objects are achieved by the combination of features of claim 1. According to one embodiment of the present invention, the inner and outer band portions are provided each with an ear-like structure of complementary shape and so arranged that the ear-like structure in the inner band portion is able to engage from within the ear-like structure in the outer overlapping band portion, whereby at least the inner band end portion is connected with the overlapping outer band portion and preferably also the outer band end portion is connected with the overlapped inner band portion by any known type of connection. According to another embodiment of the present invention, the hose clamp with a double-layer ear-like structure can be made stepless along its internal clamping surface by the use of an insert member provided at each end with a tongue-like extension adapted to engage into a tongue-receiving channel provided in both the inner and outer band portions. The insert member is thereby additionally connected with the outer band portion by any known type of connection. In another embodiment according to the present invention, the stepless clamp described above in accordance with the present invention is further improved by the use of sections imparting elastic stretchability to the clamping band. According to the present invention, these sections are constituted by undulations or corrugations both in the inner and outer band portion and of complementary shape so that the section or sections in the inner band portion can engage in nested relationship in the complementary section or sections in the outer band portion. Preferably, such sections are provided to both sides of the ear-like structure. In order to be able to further controllingly increase the holding ability and/or re-tightening forces of the ear-like structure in a hose clamp of the type described above, the present invention provides in a still further modified embodiment an external strengthening member whose main portion has a thickness that is a multiple of the band thickness and whose tapering lateral portions engage with the inner ends of the ear-like structure. In another embodiment of the present invention, two or more spring-like members of steel are used which are slipped over the plastically deformed ear to affect holding and spring characteristics of the ear-like structure in a controlled manner. BRIEF DESCRIPTION OF THE DRAWINGS These and other objects 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, several embodiments in accordance with the present invention as claimed, and wherein: Figure 1 is a perspective view of one embodiment of a hose clamp in accordance with the present invention having a strengthened ear-like structure with the parts thereof shown in the non-tightened condition of the ear-like structure; Figure 2 is an axial elevational view of the hose clamp of Figure 1; Figure 3 is a partial axial elevational view, similar to Figure 2, with the ear-like structure plastically deformed in the installed condition and illustrating a preferred arrangement of the free ends of the inner and outer band end portions in accordance with the present invention; Figure 4 is a perspective view, similar to Figure 1, of a modified embodiment of a hose clamp with a strengthened ear-like structure in accordance with the present invention and providing a stepless internal clamping surface, with the parts thereof shown in the condition prior to plastic deformation of the ear-like structure; Figure 5 is an axial elevational view of the clamp of Figure 4; Figure 6 is a perspective view, similar to Figure 4, of a still further modified embodiment of a hose clamp with a strengthened ear-like structure in accordance with the present invention in which elastic stretchability is imparted to the clamping band; Figure 7 is a partial axial elevational view of the embodiment of Figure 6; Figure 8 is a partial axial elevational view of still another embodiment of a hose clamp with a strengthened ear-like structure in accordance with the present invention in which the double ear-like structure of Figures 1-3 is further strengthened by an external strengthening member; and Figure 9 is a partial elevational view, similar to Figure 8, in which the plastically deformed ear-like structure is strengthened by two or more spring clamp members externally mounted over the plastically deformed ear-like structure. DETAILED DESCRIPTION OF THE DRAWINGS Referring now to the drawing wherein like reference numerals are used throughout the various views to designate like parts, and more particularly to Figures 1 and 2, reference numeral 10 designates therein a hose clamp in accordance with the present invention which includes a clamping band 11 made of any suitable material such as galvanized steel or stainless steel. The clamping band 11 is of such length in relation to the object to be fastened thereby, such as a hose, as to provide an overlap within the areas of the inner band end portion 11a and the outer band end portion 11b. The overlapping band portions 11a and 11b are provided with an ear-like structure generally designated by reference numeral 12 which consists of an ear-like structure 12a in the inner overlapped band portion 11a and an outer ear-like structure 12b in the overlapping outer band portion 11b. In a preferred embodiment, the ear-like structures 12a and 12b are so-called "Oetiker" ears which consist, as known, of generally outwardly extending leg portions interconnected by a bridging portion. The bridging portion of each ear-like structure 12a and 12b is thereby provided with a reinforcement, i.e., with reinforcement 13a in the bridging portion of the inner ear-like structure 12a (Figure 2) and with reinforcement 13b in the outer ear-like structure 12b (Figure 1). The ear-like structures 12a and 12b are thereby of complementary shape so that the inner ear-like structure 12a can engage into the outer ear-like structure 12b from within the hose clamp to provide a mutually nested relationship of these two ear-like structures 12a and 12b. The reinforcements 13a and 13b may be of any known construction but preferably are of the type described in my aforementioned copending application Serial No. 06/922,408, according to which each of the reinforcements 13a and 13b is formed by a relatively shallow depression substantially rectangular in plan view with the length and width of a rectangular depression extending over substantial portions of the length and width of the respective bridging portion in its non-reinforced condition and at least over more than half the length and width. The bottom of the shallow depression is either relatively flat or curved with a relatively very large radius of curvature as described in the aforementioned copending application. As mentioned above, the structural details disclosed in the aforementioned copending application which are applicable to the reinforcements 13a and 13b in the bridging portions of the ear-like structures 12a and 12b of this invention are also disclosed in the corresponding already published British Patent 2,160,577. The outer band portion 11b is connected with the inner band end portion 11a by way of a first connection 14 which may be of any known type, such as welding, riveting, inwardly or outwardly extending hooks of any known type engaging in corresponding apertures in the other band portion, or may also be of so-called "TOX" connections developed by the Tox Corporation. In a preferred embodiment of the present invention, the outer band end portion 11b is connected with the inner band portion by way of a second connection 15 which may also be of any conventional known type and is preferably similar to that of the first connection 14. Tests with a band strap as disclosed in U.S. Patent 4,430,775 have indicated that the holding ability with a fold consisting of two layers of band material did not significantly improve and in fact corresponded substantially only to a fold made from a single layer of band material. Similar results were obtained even when the outer band end portion was connected with the inner band portion, i.e., when only a connection corresponding to the connection 15 was provided. However, a surprising improvement with a double-band ear-like structure could be noticed when the inner band end portion was connected with the overlapping outer band portion, i.e., with the use of a connection corresponding to the first connection 14 of this invention. A still further substantial improvement in the holding ability of the ear-like structure and of the elastic re-tightening characteristics of the hose clamp were attainable by the use of both the first and second connections 14 and 15 in accordance with the present invention. Additionally, the arrangement as disclosed in the U.S. Patent 4,430,775 revealed a strong tendency of disengagement of the band strap which would be totally unacceptable in hoses clamps. While the arrangement of U.S. Patent 4,430,775 may well be adequate as a banding strap, according to the aforementioned test results, it would be unsuitable for use as a hose clamp or the like. The holding strength of the ear-like structure 12 in a hose clamp as shown in Figures 1 and 2 of the present invention increased by more than 75% of the maximum holding strength of a hose clamp made from the same material and with an arrangement as disclosed in the U.S. Patent 4,430,775. A further advantage obtainable with the present invention resides in the fact that, for example, riveted connections are not directly stressed during closing of the clamp by contraction of the so-called "Oetiker" ear because the clamping band material is extended twice over the ear-like structure. A simple riveted connection therefore suffices for the clamp structures in accordance with the present invention. Figure 3 illustrates a clamp structure such as shown in Figures 1 and 2 after plastic deformation of the ear-like structure 12 in which a cost-efficient and material saving arrangement is realized by relatively short band end portions 11a and 11b in conjunction with the so-called "TOX" system which eliminates the need for punching out band material normally required, for example, in connection with riveted connections. Figures 4 and 5 illustrate a modified embodiment of a hose clamp as shown in Figures 1 and 2 in which with the use of an insert member generally designated by reference numeral 20 a gap-free stepless configuration of the inner clamping surface is achieved. The insert member 20 includes a main portion 21 provided at each free end with a tongue-like extension 22 which is adapted to engage in a tongue-receiving means formed by a pressed-out channel 17 in the center area of the outer band portion which leaves lateral non-pressed-out portions 18 on both sides thereof. The pressed-out central channel 17 thereby commences at a first step-like portion 19 raising the lateral portions 18 to the radial distance of the pressed-out channel 17 and terminates in a second step-like portion 16 located in the clamping band 11 from the first step-like portion 19 in a direction opposite the ear-like structure 12. As can be seen in Figures 4 and 5, tongue-receiving channels 17 are provided on both sides of the ear-like structure 12 in the inner and outer band portions 11a and 11b whereby the insert member 21 is connected with the outer band portion 11b at a further connection 24 which may be similar to the connections 14 and 15. The pressed-out channel portion 17 is thereby separated by one or several cuts from the lateral band portions 18. In lieu of the pressed-out channel portion 17, it is also possible to provide an aperture as shown, for example, in Figure 12 of my prior U.S. Patent 4,315,348. In the arrangement according to Figures 4 and 5, the gap underneath the ear-like structure 12 is bridged by the insert member 21 whereby the tongue-like extensions 22 in conjunction with the tongue-receiving means 16, 17, 18 and 19 avoid the formation of any steps due to overlap. The embodiment of Figures 6 and 7 differs from the embodiment of Figures 4 and 5 in that sections generally designated by reference numeral 30 are provided in the inner and outer band portions 11a and 11b to impart elastic stretchability to the clamping band 11. The sections 30 are thereby in the form of complementary undulations or corrugations 31a and 31b, preferably on both sides of the ear-like structure 12 which are so arranged and constructed that an inner undulation or corrugation 31a is able to nest within a corresponding outer undulation or corrugation 31b. As a result of the sections 30, additional elastic stretchability is imparted to the clamping band which can be increased by the provision of several such undulations in each section. Furthermore, the sections 30 are not limited to undulations or corrugations but may also have shapes such as disclosed in my prior copending application Serial No. 07/409,798, filed on September 20, 1989 and entitled "Earless Clamp," in which elastic stretchability is imparted to the clamping band according to this copending application by one or more sections having non-linear lateral band portions symmetrically arranged with respect to the band center longitudinal plane and separated from each other by a centrally disposed opening which is in the shape resembling an hourglass. Figure 8 illustrates a still further modified embodiment in accordance with the present invention in which the double-band ear-like structure 12 is externally surrounded by a strengthening member generally designated by reference numeral 35. The strengthening member 35 includes a main portion 36 and two lateral portions 37 which are convexly curved and taper in the direction toward their free ends 39 that are preferably rounded-off with a radius of curvature smaller than the radius of curvature of the transition from the clamping band 11a, 11b into the leg portions of the so-called "Oetiker" ear 12 illustrated in Figure 8 in its plastically deformed condition. The main portion 36 of the strengthening member 35 is thereby made of a thickness which is significantly greater than the thickness of the clamping band and also considerably greater than the thickness of the nested double layer of the clamping band and can be made thinner or thicker depending on the required strength for tensional forces expected in the clamping band 11. The internal surface of the main portion is thereby substantially rectilinear, passing over into the internal surfaces of the lateral portions 37 by way of rounded-off portions while the external surface 38 of the main portion 36 is preferably slightly convexly curved so that maximum thickness of the main portion 36 occurs near the middle thereof. However, the external surface 38 can also be made substantially parallel to the internal surface thereof. The clamp structure shown in Figure 8 is preferably tightened about an object to be fastened such as a hose, by applying a deformation force onto the lateral portions 37 which, in turn, will cause deformation of the plastically deformable ear-like structure 12 to assume its illustrated approximately omega shape typical for so-called "Oetiker" ears. The holding ability of the ear-like structure, already increased by the use of a double material layer can be further greatly increased by the presence of the external strengthening member 35 whose design is thereby so chosen that it does not totally eliminate the residual elasticity of the plastically deformed ear-like structure to compensate for changes in temperature and/or pressure. However, the ear-like structure can be readily adapted in its characteristics to the required or needed characteristics for holding ability, strength, etc. by selection of a correspondingly designed strengthening member 35. A pincer-like tool with internal jaw surfaces matched to the curved external surface of the lateral portions 37 can be used for purposes of deforming the ear-like structure 12, 35. Figure 9 illustrates a modified embodiment of a clamp structure shown in Figures 1 and 2 of the present invention in which an extraordinarily favorable spring elasticity and re-tightening force can be achieved with the use of two or more spring clamps 135 which are made of spring steel. These spring clamps 135, which have a more or less part-circular shape, can be easily mounted over the plastically deformed ear-like structure 12, previously plastically deformed in the usual manner, by merely elastically opening up the clamp members 135 from their normal smaller configuration so that they can be slipped over the ear-like structure, respectively, another already installed clamp member 135. The end portion 139 of the clamp members 135 thereby have a shape at least approximately corresponding in its installed condition to the external shape of the inner leg portions of the plastically deformed ear-like structure 12 so that they can be mounted in a number depending on need, over the plastically deformed ear-like structure 12 to obtain the desired holding strength coupled with desired optimum re-tightening forces, which is important for use with hoses carrying a fluid subjected to temperature and/or pressure changes, for example, coolant hoses in internal combustion engines. The spring clamps 135 in accordance with the present invention, which can be readily mounted over the plastically deformed ear, will thus serve to solve numerous sealing problems in an extraordinarily simple manner. Additionally, depending on requirements, the possibility exists to attain with the use of the present invention of Figure 9 a hose connection which will completely satisfy by simple means the needs of a given situation, i.e., be it a simple hose connection or a high pressure hose connection. Unlimited possibilities are thus attainable with the reinforced ear-like structure according to the present invention regardless of whether the clamping band is made of conventional steel having a tear strength of about 40 kg. per mm 2 or of stainless steel having a tear strength in excess of 100 kg. per mm 2 . The use of the spring clamp members according to Figure 9 therefore offers practically unlimited versatility in the connections attainable therewith, whereby the range can of course also be increased by the use of thicker band material.

Claims: A hose clamp which includes a clamping band (11) with overlapping band portions (11a, 11b) and means (12) for tightening the clamp which includes ear-like means (12a, 12b) in each of the overlapping band portions (11a, 11b), wherein the ear-like means (12a, 12b) are of complementary shape to enable a nested relationship with the ear-like means (12a) in an inner band portion (11a) engaging from within the clamp into the ear-like means (12b) in an outer overlapping band portion (11b), including first means (14) within an area of the inner overlapped band portion (11a) following its ear-like means (12a) in the circumferential direction toward its free end for connecting at least a free end portion of the inner overlapped band portion (11a) to the corresponding overlapping outer band portion (11b). The hose clamp of claim 1, including second means (15) within an area of the outer overlapping band portion (11b) following its ear-like means (12b) in the circumferential direction toward its free end for connecting the free end portion of the outer overlapping band portion (11b) to the corresponding overlapped inner band portion (11a). The hose clamp of claim 1 or 2, wherein each clamping band end portion (11a, 11b) is relatively short in the circumferential direction so as to minimise material waste, yet sufficiently long to accommodate a respective one of the connecting means (14, 15). (Figure 3) The hose clamp of any preceding claim, wherein each ear-like means (12a, 12b) is plastically deformable and includes two outwardly extending leg portions interconnected by a bridging portion provided with reinforcing means (13a, 13b), wherein each reinforcing means (13a, 13b) is formed by a shallow, generally pan-shaped depression having a substantially rectangular configuration as viewed in plan view whose sides constituting the width and length of the rectangular configuration extend substantially rectilinearly over more than half the width, respectively, length of the bridging portion. The hose clamp of any preceding claim, further including means (20) assuring a stepless, gap-free internal clamping surface which includes an insert member (21) internally covering the circumferential area of overlap of the overlapping inner and outer band portions and having tongue-like extensions (22) at the free ends of the insert member (20), wherein tongue-receiving means (16, 17, 18, 19) are provided in the clamping band for each of the tongue-like extensions, and wherein the insert member (20) is connected to the clamping band (24). (Figures 4-6) The hose clamp of claim 5, wherein the insert member (20) is connected to a part of the clamping band forming the outer band portion (11b) and on the side of the ear-like means (12a, 12b) opposite the free end of the outer band portion (11b). The hose clamp of claim 6, wherein a respective tongue-receiving means includes a pressed-out channel (17) extending in the clamping band circumferential direction within the central area thereof while leaving on each side a lateral clamping band portion (18), and wherein the pressed-out channel commences within the area of a step-like portion (19) displacing the lateral clamping band portions to the radial level of the channel (17). The hose clamp of any preceding claim, including additional means (30) in the overlapping band portions within an area excluding the ear-like means to impart elastic stretchability to the clamping band in the band circumferential direction, and wherein the additional means are formed by corrugation-like sections (31a, 31b) in the overlapping band portions (11a, 11b) of complementary shape to enable corresponding corrugation-like sections to assume a nested relationship with one another. The hose clamp of claim 8, wherein the overlapping band portions (11a, 11b) are provided with complementary corrugation-like sections (31) on both sides of the ear-like means (12a, 12b). The hose clamp of any preceding claim, including separate means (35; 135) for increasing the holding ability and elastic re-tightening forces of the ear-like means (12a, 12b), which includes at least one external spring member (35; 135) of generally convex shape mounted over the ear-like means (12a, 12b) with the free ends of the spring member (35; 135) in engagement with the inner area of the leg portions of the ear-like means (12a, 12b). The hose clamp of claim 10, wherein the separate means (135) includes several generally part-circular steel spring members (135') in mutually nested relationship mounted over the ear-like means (12a, 12b) (Figure 9). The hose clamp of claim 10, wherein the ear-like means (12a, 12b) have leg portions, wherein the separate means includes an external strengthening member (135) having a main portion (36) adjoined by curved lateral portions (34) terminating in tapering end portions in engagement with the inner area of the leg portions, and wherein the main portion (36) has a thickness which is a multiple of the thickness of the clamping band. (Figure 8). The hose clamp of claim 12, wherein the inner surface of the main portion (36) is at least approximately rectilinear and passes over into the inner surfaces of the lateral portions (37) by way of curved portions, and wherein the external surface (38) of the main portion (36) is convexly shaped having its greatest thickness in the centre area.

Inventors: OETIKER HANS, OETIKER, HANS
Applicants: OETIKER HANS MASCHINEN, HANS OETIKER AG MASCHINEN- UND APPARATEFABRIK
Application year: 1992
Main classification: F16L33
IPC codes: F16L33, F16B2