CA1274069A

CA1274069A - Hose clamp

Info

Publication number: CA1274069A
Application number: CA000480398A
Authority: CA
Inventors: Hans Oetiker
Original assignee: HANS OETIKER AG MASCHINEN-UND APPARATEFABRIK
Current assignee: HANS OETIKER AG MASCHINEN-UND APPARATEFABRIK
Priority date: 1984-06-20
Filing date: 1985-04-30
Publication date: 1990-09-18
Anticipated expiration: 2007-09-18
Also published as: ES287556U; SE503537C2; ATA182085A; NL8501723A; JPH0542598B2; SE8502915D0; NL192538C; SE8502915L; DE3521906A1; SE460986B; IT8520958A0; BR8502566A; BE902701A; ES287556Y; NL192538B; FR2566507A1; CH668460A5; GB2160578B; IL75216A0; AT384465B

Abstract

A B S T R A C T

An open clamp structure capable of withstanding very high tightening forces, with a clamping band whose over-lapping inner and outer band portions are mechanically locked by a mechanical interconnection including outwardly extending hooks near the free end of the inner band portion adapted to engage with apertures near the free end of the outer band portion; for purposes of tightening the clamp structure upon engagement of at least one hook in the corresponding aperture, a deformable ear with two generally outwardly extending leg portions interconnected by a bridging portion is provided, whereby the bridging portion includes reinforcing means; at least one of the hooks is thereby a cold-deformed hook having force-engaging surface means while another hook is a combined guide and support hook having inclined guide and support surface means formed by its rear edge facing away from the free end of the inner band portion; the reinforcing means is in the form of a generally pan-shaped depression extending over a substantial part of the length and width of the bridging portion.

Description

7~
The present invention relates to a clamp structure capable of withstanding very high tightening forces.
Clamp structures of the type to which the present invention relates normally fall into two categories; namely, endless clamps and open clamps. The present invention is concerned in particular with the latter type of clampsO
These open type of clamp structures require some kind of mechanical connection between the overlapping band ends before the clamp can be tightened about the object to be 'O fastened. Tightening of the clamp can thereby be achieved in various ways, for example, by so called screw-type mech-anisms or by means of a plastically deformable ear or ears, as disclosed in my prior U.SO Patent 2,614,304 and my prior U.S. Patent 3,082,498 which have become known as "Oetiker"
1~ ears.
More specifically, the present invention is concerned with a clamp structure utilizing a mechanical interconnection between the overlapping band portions by means of hooks extending outwardly from the inner band portion engaging in apertures in the outer band portion, and by the use of one or more so-called "Oetiker" ears for tightening the clamp structure about the object to be fa$tened. Such clamp structures are faced with two problems. On the one hand, any step or offset along the inner diameter of the clamp structure as a result of overlapping band portions may be the source of a possible leakage when the clamp structure is installed. However, this problem has been solved by the so-called stepless clamp structure as disclosed in my prior U~S. Patent. 4,315,348. The second problem ~aced by such clamp ~;

~ ¦_~d 7~ .?~
structures is the sufficient holding ability thereof once installed. This, in tu.rn, depends, on the one hand, on the magnitude of the forces with which the clamp can be closed by plas-tic de~ormation of the ear without jeopardi2ing the intended compensating ~unction of the ear and, on the other, on the ability of the mechanical connection to withstand the high forces with which the ear is deformed ~o contract the clamping band. Irnprovements in both aspects have been a.chieved heretofore by the provision of reinforcing grooves in the bridging portions o~ the "Oetiker" ears as disclosed in my prior U.S. Patent 3,402,436. These prior art reinforc-ing grooves were more or less of V--shaped configuration as viewed in transverse cross section through the bridging portion in a plane containing the axis of the clamp structure and more or less in the shape of a canoe or small row boat as viewed ~rom above. While these prior art rein~orcing grooves proved extraordinarily successEul, the development o~ new plastic materials of ever-increasing hardness such as "HYTRELL"* used in practice with relatively small thick-nesses, require ever-increasing clamping forces to assure complete tightness.
The ability to apply higher closing or tightening forces has been considerably improved by the mechanical connection disclosed in my prior U.S. Patent 4,299,012 which involves two cold-deformed support hooks and a tab-like guide hook extending outwardly Erom the inner band portion and adapted to engage in corresponding apertures formed in the outer band portion, whereby the guide hook primarily serves to guide the two band portion5 toward one another until such time as the cold-deformed support hooks become operable b~ engagement of their force-engaging surfaces with corresponding *Tracle Mark ,, ;

apertures. However, the mechanical connection as disclo~ed in my prior U.S. Patent 4,299,012 entails certain dlsad-vantages stemming from the fact that the clamp structures as disclosed, for example, in Figure 7 of this patent, are normally stamped-out from flat band material and are shipped, for reasons of economy, as flat blanks from the place of manufacture to the location of use thereof, where they are preformed into substantially circular shape prior to assembly of the object to be fastened, as disclosed, for example, in my prior U.S. Patent No. 4,425,781. In the automatic machines used for the manufacture of the flat blanks, the angle of the guide hook is the same with the use of the same die.
Thus, in the flat blank, the guide hook always has a predeter-mined angle. However, this angle will vary in the installed condition, depending on the diameter of the clamp structure.
This then may require special attention and possi~le remedial action to maintain optLmum conditions for the angle of the guide hook in the assembled condition of the clamp. Addi-tionally, the guide hook which is not intended to absorb any significant tightening forces, is formed in this prior patent by a substantially rectangular tab-like member punched-out of the band material, thereby leaving a corresponding aperture in the band material. This, in turn, may lead to a tendency of the band material to buckle within the area where the band material has been reduced by the punched-out guide hook when the flat blank is bent into the approximately circular shape of the clarnp.
Accordingly, it is a principal object of the present invention to provide a clamp structure which avoids the aEorementioned shortcomings and at the same time permits the ~f~

use of ever-higher closing or t:ightening foxces to assure, complete tightness of the installed clamp even with relatively thin, very hard plastic hose materials, such as used in conW
nection with axle boots in the automotive industry~
The underlying problems are solved according to the present invention in that the clamp structure according to the present invention utilizes an ear provided with a rein-forcing means of generally pan-shaped, relatively shallow configuration having a length and width corresponding to at least a substantial part of the length and width of the bridging portion and in that the mechanical connection between the overlapping inner and outer band portions include at least two hooks, one of which is a cold-deformed support hook and the other is a combined guide and support hook formed lS by a tab-like member extending generally in the longitudinal direction of the clamping band.
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 accompanyiny drawing which shows, for purposes of illustration only, one embodiment in accordance with the present invention, and wherein:
Figure 1 is a perspective view of an open clamp structure in accordance with the present invention prior to its assembly 25 over the object to be fastened but preformed into circular shape;
Figure 2 is a side elevational view of a part of the clamp s~ructure illustrated in Figure l;
Figure 3 is a plan view on the clamp structure of Figure 1, as flatterled out Figure 4 is a side view, similar to Figure 2, and showing the inner and outer band portions in the assembled condition;
and Figure S is a top plan view on the assembled clamp structure o~ Figure 4.
Referring now to the drawing wherein like reference numexals are used throughout the various views to designate like parts, and more particularly to Figure 1, the clamp structure generally desi~nated by reference numeral 10 10 includes a clamping band 11 having an inner band end portion 12 and an outer band end portion 13 which are intended to overlap one another in the install d condition. The inner band portion 12 terminates in a tongue portion 15 adapted to engage in a channel-like recess formed by the pressed-out portion 16 and the steps 17 and 18 to provide a stepless internal configuration of the clamp as disclosed in my prior U.S. Patent 4,315,348.
- Additionally, the clamp structure 10 includes an ear generally designated by reference numeral 20 consisting of two generally outwardly extending leg portions 21 intercon-nected by a bridging portion 22 which, in turn, is provided with a reinforcing means generally designated by reference numeral 23. The reinforcing means 23 is in the shape of a relatively shallow, generally pan-shaped depression including a bottom part 24 as well as longitudinal and transverse con-necting portions 25 and 26 connecting the bottom part 24 with the remaining non-depressed bridging portion 22. As can b~ seen from ~he d:rawing, the bottom part 24 is relatively flat over at least a subs-tantial part o~ its length and width.
However, if so des.ired, the bottom part may also have a slight ~ 3~ 3 curvature, particularly a concave curvature with a relatively large radius of curvature.
As can be seen from Figures l, 3 and 5, the longitudinal connecting portions 25 and the transverse connecting portions 26 extend at an angle of nearly 90 with respect to the bottom part 24 and the remaining non-depressed bridging portion 22. In a preferred embodiment, this angle differs from a 90 angle by no more than about 20. The connecting portions 25 and 26 pass over into the bottom part 24 and into the remaining non depressed bridging portion 22 by way of rounded-off corners of relatively small radii of curvature. These radii of curvature may be the same or may differ from one another and also need not be radii of curvature of constant length in a given corner.

The area occupiad by the bottom part 24 should be at lPast 35~ of the area occupied by the non-reinforced bridging portion, i.e., the area occupied by the bridging portion 22 before the reinforcing means 23 is formed, and preferably occupies between about 40% to about 60% thereof.

By the use of the ear 20 in accordance with the present invention, the length of the leg portions 21 can be decreased compared to the length used heretofore without impairment o~ the holding ability of the ear structure or its compensating properties for temperature and/or pressure changes. this is true also if relatively thicker material is used for the clamping band to further increase the tightening forces which can be applied to the ear structure during contraction oP the clamp.

The mechanical interconnection generally designated by reference numeral 30 according to the present invention between the overlapping inner and outer band portions 12 and 13 includes one or more cold-deformed hooks 3~, in the ilius-trated embod~nent, two such cold-deformed hooks 31 which . . .
have force-engaginy abutment surfaces 32 and are constructed as disclosed in my prior U.S. Patent 4,299,01~. As described in this last-mentioned patent, each cold-deformed support hook 31 is integral with the adjoining parts of the band material on all sides thereof except within the area of a generally transversely extending cut which results in the force-engaging abutment surface 32. The support hooks 31 are adapted to engage in rectangular apertures 36 in the outer band portion as also disclosed in my last-mentioned patent. According to the present invention, in addition to the cold-defo~ned support hooks 31, a combined guide and support hook 33 is provided which is punched and pressed-out of the inner band portion 12 and extends at substantially right angle to the outer sur-face of the band material. The outer band portion 13 is pro-vided with a relatively narrow slot 37 for receiving the combined guide and support hook 33. To perfonn the guide function, the rear edge 34 of the combined guide and support hook 33, which faces away from the free end of the inner band portion 12, is inclined rearwardly outwardly so as to guide the inner and outer band portions 12 and 13 toward one another when the clamp structure is tightened about the object to be fastened. The tab-like combined guide and support hook 33

2~ as well as the slot 37 are preferably located within the area of the lonqitudinal center axis of the band. This leaves unequal c~noun-ts of b~nd material on the two sides of the combined guide and support hook 33 due to the fact that the area on

3 ~ 7~
one side thereof is reduced by the existence of the openi.lg corresponding to the area of the punched-out combined guide and support hook 33. The combined guide and support hook is, for example, in the shape of a parallelogram leaving an opening of corresponding configuration. However, it is understood that the configuration and shape of the combined guide and support hook 33 may also be different from that shown in the drawing to match particular requirements as known to those skilled in the art.
During assembly, the combined guide and support hook 33 is extended through the slot-like aperture 37 whereafter tightening of the clamp is commenced by plastic deformation of the ear 20, for example, with the use of pneumatic pincers applied to the inner ends of the leg portions 21. As a result of the resulting circumferentially directed closing or tighten-ing forces, the inclined guide and force-engaging surface 34 causes the inner and outer band portions 12 and 13 to move toward one another until, duriny continuing tightening, the cold-deformed support hooks 31 become effective to absorh tightening forces by engagement with the respective apertures 36. The combined guide and support hook 33, by reason o~ its par~icular configuration and construction, thus not only performs a guide function but also a support function until its support function is assisted by the cold-deformed support hooks 31.
Howe~er, even after the cold-deformed support hooks 31 become effective, the combined guide and support hook 33 will continue to assist in the support function since it is able tO absorb longitudinally directed forces without bendin~. Furthermore, the likelihood of buckling on the part of the band material within the area of the combined guide and support hook 33 ~ '7~
is effectively precluded due to the resistance offered by the substantial amount of band material present on one side of . .
the combined guide and support hook.
Additionally, the combined guide and support hook 33 offers the possibility to pro~ide a permanent mechanical con-nection between the open ends of the clamp structure b~ a rivetiny action, for example, as disclosed in my U.S. Patent 3,286,314.
In practice with one particular clamp, it has been possible 'O to increase the closing force of the ear, utilizing the same material as indicated by the following tabulation:

Sample Band Dimension Average Tensile Closing Tightness Strenqth _ Force_ B
A 9 x 0.8 ~m 470 N/mm 380 kp from 0 to 1.8 bar B 9 x 0.8 mm 470 N/mm 460 kp from 0 to 2 bar - C 9 x 0.8 mm 470 N~mm 550 kp from 0 to 2.2 bar D 10 x 1 mm. 500 N/mm 800 Kp from 0 to 3.4 bar 2~ (*bellows burst at 3.4 bar) wherein A is a clamp with prior art reinforcing groove and mechan-ical interconnection according to U.S. Patent 4,299,012.
B is a clamp with reinforc~d ear according to the present ~5 invention and mechanical interconnection according to U.S. Patent

4,299,012.
. C is a clamp with reinforced ear according to the present invention and mechanical interconnection according to the present invention.

^~ D is a clamp with reinforced ear according to the present invention and mechanical interconnection according to the present invention, utilizing a thicker and wider material.

~;~7~

As can be seen from the foregoing tabulation, the present invention not only permits a s~stantial increase of the closing or tightening forces to be applied to the ear which the mechanical co~nection is able to withstand, but also pexmits a wider and thicker band material whicn in turn permits a still further increase in the closing force applied to the ear.
Additionally, the reinforced ear according to the present invention permits the ear to be kept lower than with the prior art reinforcement. Whereas the height of the ear in examples A and B amounted to 6.2 mm., the height in examples C and D
could be decreased to 5 mm.
Tests with clamps embodying the present invention have demonstrated thaq clamps with the reinforcement in the bridging portion of the ear according to this ~nvention permit an in-crease of about 150~ in the strength of the clamp over clamps with the prior art reinforcement in the ear thereof.
While I have shown and described only one e~bodiment in accordance with the present invention, it is u~derstood that the same is not limited thereto but is susceptible of numerous changes and modification~ as known to those skilLed in the art, and I therefore do not wish to be limited to the details shown and described herein but intend to cover all such changes and modifications as are encompassed by the scope of the appended claLms.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A clamp structure capable of withstanding very high tightening forces, comprising clamping band means providing in its closed condition an inner band portion and an outer band portion each terminating in a free end, mechanical interconnecting means adapted to close the clamping band means into a closed clamp structure including outwardly extending hook means near the free end of the inner band portion adapted to engage with aperture means near the free end of the outer band portion, means oper-able for tightening the clamp structure circumferentially about an object to be fastened after engagement of at least one hook means in the corresponding aperture means including deformable ear means, each ear means including two generally outwardly extending leg portions and a bridging portion between said leg portions, said bridging portion being provided with reinforcing means, at least one of said hook means being a cold-deformed hook having force-engaging abutment surface means while another hook means is a pressed-out tab-like hook extending in the longitudinal direction of the band means, and said reinforcing means being in the form of depression means extending in the longitudinal direction of the band means and of generally pan-shaped, relatively flat configuration with the area of said depression means occupying at least about 35% of the area of the bridging portion in its non-reinforced condition.

2. A clamp structure according to claim 1, wherein the area of said depression means is about 40% to 60% of the area of the bridging portion in its non-reinforced condition.

3. A clamp structure according to claim 2, wherein a respective depression means includes a bottom portion which is relatively flat.

4. A clamp structure according to claim 3, wherein the leg portions have a length of the order of 5 mm, and wherein a respective bottom portion is recessed from the non-recessed bridging portion by a distance less than the length of the leg portions but approaching the order of 5 mm.

5. A clamp structure according to claim 3, wherein the leg portions are relatively short, and wherein a respective bottom portion is recessed from the non-recessed bridging portion by a distance less than but approaching the length of the leg portions.

6. A clamp structure according to claim 2, wherein the sides of the bridging portion extending in the longitudinal direction of the clamping band means are curved concavely so that the width of the bridging portion in its area near the leg portions is greater than in the central area between the leg portions.

7. A clamp structure according to claim 2, wherein a respective depression means includes a substantially flat bottom portion and connecting portions extending generally in the longitudinal and transverse direction which form an angle approaching 90° with respect to the bottom portion and the remaining non recessed bridging portion.

8. A clamp structure according to claim 7, wherein said connecting portions pass over into the bottom portion and the remaining non-recessed bridging portion with rounded-off corners of relatively small radii of curvature.

9. A clamp structure according to claim 1, wherein said tab-like hook has inclined guide and support surface means formed by its rear edge facing away from the free end of the inner band portion, said guide and support surface means extending obliquely rearwardly upwardly.

10. A clamp structure according to claim 9, wherein said another hook means is of approximately parralelogram-shaped configuration.

11. A clamp structure according to claim 2, wherein the tab-like hook is so pressed-out of the band material of the inner band portion that a larger amount of band material, as viewed in the transverse direction, is left on one side than on the other side of said another hook means to thereby increase resistance to buckling.

12. A clamp structure according to claim 11, wherein the larger amount of band material is left on the side of the opening in the inner band portion formed by the pressed-out tab-like hook which is adjacent the tab-like hook.

13. A clamp structure according to claim 11, wherein more band material is left on one side of said tab-like hook than on the other side thereof.

14. A clamp structure according to claim 13, further comprising means including a tongue-like extension at the free end of the inner band portion operable to engage in an outwardly-stepped recessed area of the outer band portion to provide a stepless inner configuration over the entire circumference of the clamp structure.

15. A clamp structure according to claim 13, wherein the aperture means receiving the another hook means is a relatively narrow slot leaving substantial material around the same to permit absorption of considerable tightening forces.

16. An open clamp structure capable of withstanding very high tightening forces, comprising clamping band means providing in its closed condition an inner band portion and an outer band portion each terminating in a free end, mechanical interconnecting means including outwardly extending hook means near the free end of the inner band portion adapted to engage with aperture means near the free end of the outer band portion, means operable for tightening the clamp structure about an object to be fastened after engagement of at least one hook means in the corresponding aperture means including deformable ear means, each ear means including two generally outwardly extending leg portions and a bridging portion between said leg portions, said bridging portion being provided with reinforcing means, further means operable in the closed clamp structure to assure a substantially smooth gap-free transition devoid of any step in the circumferential direction from the free end of the inner band material to the ring-like configuration formed by the adjoining band portion of the band means, at least one of said hook means being a cold-deformed hook having force-engaging abutment surface means while another hook means is a tab-like, pressed-out member which extends generally in the longitudinal direction of the band means, and said reinforcing means being formed by generally pan-shaped depression means whose area encompasses at least abot 35%
of the non-reinforced area of the bridging portion.