Bellows-type cover with integrated clamping member

Abstract: A bellows-type cover into which a clamping member is adapted to be securely integrated to form a preassembled unit; the groove-shaped recess (20) near one end of the bellows-type cover (10) adapted to receive the clamping member has a two-tier positioning arrangement (11) with a radially inward, circumferentially extending bottom surface (26) for engagement by the clamping member when fully tightened and with a temporary bottom (22a, 22b) for the clamping member to provide a releasable self-retaining support for the closed, but not yet fully tightened clamping member at a radial distance between the bottom surface (26) and the radially outer limit of the recess (20).

Description: FIELD OF THE INVENTION The invention relates to a bellows-type cover made from elastic material, such as rubber or plastic material, used, for instance, for the protection of universal joints and drive shafts in which a clamping member or members such as hose clamps or shrinkable compression rings are integrated with the bellows-type cover. BACKGROUND OF THE INVENTION Flexible or elastic bellows-type covers usually of accordion-like construction, such as axle boots for universal joints or for drive shafts must be carefully sealed to protect the lubricant. Such bellows-type covers have been used extensively in the automotive industry, for example, with front-wheel drive vehicles. They are normally fastened to the axle stub shafts by means of hose clamps or shrinkable compression rings. A need exists at present on the part of manufacturers of universal joint shafts or drive shafts for bellows-type covers in which clamping members in the form of "Oetiker" hose clamps or "Oetiker" shrinkable compression rings are already integrated into the bellows-type covers. In other words, the manufacturers desire a product in which the clamping members are already integrated at or in the bellows-type covers which favors the automatic assembly of the universal joint or drive shafts in that the bellows-type covers provided with integrated clamping members are available as preassembled parts so as to avoid the need for mounting the clamping members on the bellows-type covers only at the final assembly as is the case today. SUMMARY OF THE INVENTION Two possibilities exist, in principle, for a clamping member to be integrated into the bellows-type cover which consist of (1) the clamping member vulcanized into the bellows-type cover or (2) a self-holding arrangement for a clamping member adapted to be mounted on the bellows-type cover. Of these two possibilities, the first solution involving the clamping member vulcanized into the bellows-type cover can be disregarded because such an arrangement is practically not feasible with the usual hose clamps presently used as clamping members as also with compression rings used as clamping members. For example, a stepless hose clamp of the type disclosed in U.S. Patent 4,299,012, which has been used extensively with axle boots in the automotive industry, if vulcanized into the bellows-type cover, would present great difficulty of being tightened by deforming the "Oetiker" ear. The vulcanized-in solution is also unacceptable because of substantial increase in costs. A shrinkable compression ring, vulcanized into the bellows-type cover can no longer be shrunk by means of the presently available tools because these tools are designed to engage during the shrinking operation with the external surface of the compression ring having a predetermined diameter in a form-locking manner in order to reduce the compression ring in its diametric dimension by the application of radial forces. The layer of rubber or plastic material applied over the vulcanized-in shrinkable compression ring formed by the vulcanizing operation prevents a form-locking connection between the compression ring and the compression tool. Equally inappropriate are arguments that vulcanizing-in of the clamping members into the bellows-type covers provides a corrosion protection of the integrated hose clamps or compression rings because these problems can be readily avoided in the present invention by the use of appropriate materials for the clamping devices, such as stainless steel or aluminum. Furthermore, a vulcanizing-in of the clamping members precludes any visual control provided at the clamping member in the installed condition insofar as correct positioning and seating of the clamping member and proper tightening of the clamping member are concerned. Visual inspection of indications relating to manufacturer of the clamping members and/or installation dates would also become impossible. Up to the present, hose clamps used with drive or universal joint shafts have served extensively as information carriers in that dates such as assembly dates or other relevant dates of interest to the manufacturer were integrated into the clamping devices, for example, by stamping. Such visual inspections and controls are possible only as long as the clamping members are freely exposed which is not the case with a vulcanized-in solution. DE-A-4 413 664 discloses a bellows-type cover member and an assembly thereof with a clamping member, with the features included in the first part of claim 1 and claim 9, respectively. While the known arrangement tries to define the relative position of the cover and clamping members in a pre-assembly condition, the clamping member in that condition is not prevented from moving at any part of its circumference, with the possibility of the arrangement from becoming disassembled before clamping. EP-A-0 545 629 shows another bellows-type cover member with a clamping ring which is so dimensioned and pretensioned that it permits the cover member to be mounted with the ring positioned in a pre-assembly condition. Since the clamping ring is held in that condition only by its resilience, it is again exposed to the danger of becoming disengaged prior to clamping. It is an object of the present invention to provide a bellows-type cover member for a clamping member, and an assembly of such cover and clamping members, in which the clamping member is self-retained on the cover member in a pre-assembly condition. This object is met by the invention defined in claims 1 and 9. In accordance with the invention, the clamping member, which is automatically retained after being mounted on the bellows-type cover member within the recess, now forms an integrated unit with the cover member for further handling. The inwardly extending means in the recess, which form a temporary bottom for the clamping member, provides a radially outer position in which the clamping member is retained securely but only temporarily in a position from which it is released by the application of a predetermined tightening force. The term "clamping member" is used in this specification to describe both conventional clamps such as "Oetiker" stepless clamps as presently used with bellows-type cover members as also shrinkable compression rings such as "Oetiker" puzzle lock compression rings disclosed in US-A-5,001,816 and US-A-5,185,908. 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 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 partial axial cross-sectional view through an end part of a bellows-type cover in accordance with the present invention; Figure 2 is an enlarged partial axial cross-sectional view through one end of the bellows-type cover of Figure 1, showing a clamping member in the form of a compression ring in the integrated, preassembled condition; Figure 3 is an enlarged partial axial cross-sectional view, similar to Figure 2, showing the clamping member in the fully installed condition after the shrinking operation; Figure 4 is a partial elevational view of the bellows-type member with some dimensional indications; and Figure 5 is a top plan view on Figure 4. DETAILED DESCRIPTION OF THE DRAWINGS Referring now to the drawing wherein like reference numerals are used throughout the various views to designate like parts, reference numeral 10 generally designates a bellows-type cover of elastic material such as rubber or plastic material which may be of any known construction. The two-tier arrangement provided, for example, at the large end of the bellows-type cover 10 is generally designated by reference numeral 11 which is provided with a circumferentially extending, groove-shaped recess generally designated by reference numeral 20 that provides the two-tier positioning of the clamping member. Recess 20 is provided with side walls 21a and 21b spaced in the axial direction from one another a distance c (Figure 4) slightly greater than the width of the clamping member generally designated by reference numeral 40 . The radial depth d is thereby slightly larger than the thickness of the clamping member 40 . The radially outer position of the two-tier structure is formed by the at least approximately horizontally extending surfaces 22a and 22b of at least one pair, but preferably several pairs, of yieldable support members 23a and 23b extending toward one another in the recess 20 . The lower surfaces 24a and 24b of the members 23a and 23b which are triangularly shaped in cross section extend at an angle downwardly outwardly to the side surfaces 21a and 21b . The connection between the top surfaces 22a and 22b and the inclined lower surfaces 24a and 24b are preferably rounded off at 25a and 25b . The members 23a and 23b are integral with the larger end 11 of the bellows-type cover 10 and are therefore made of the same elastic material which permits yielding thereof. As shown in Figure 2, the members 23a and 23b of a pair of members of which preferably several, such as three or four, are distributed uniformly over the circumference of the recess 20 retain the clamping member 40 such as an "Oetiker" puzzle-lock compression ring in the preassembled condition in which the clamping member 40 is securely held integrated with the bellows-type cover 10 because of the self-retaining function of the upper part of the groove-shaped recess 20 disposed radially outwardly of the members 23a and 23b . Upon application of tightening forces, the members 23a and 23b , which form protruding lip-like elements, are able to yield to permit the clamping member 40 to enter the radially inward part of the groove-shaped recess 20 in which it is then firmly held in position on the bottom 26 of the groove-shaped recess as a result of the tightening, respectively, shrinking of the diametric dimension thereof. The elastic members 23a and 23b are then able to spring back to project again over the radially outer surface of the clamping member 40 in the form indicated in Figure 3 and designated by reference numeral 23a' and 23b' . As mentioned above, the use of groove-shaped recesses in the external surfaces of the ends of bellows-type covers are known. However, up to now, they merely served the purpose of guiding the clamping member in the fully installed condition. The problem of providing a two-tier arrangement in which a self-holding feature is also attained in the radially outer position would not be attainable without the use of the members 23a and 23b because even a deeper recess would not safely provide the self-retaining action necessary to constitute the clamping member as a part integrated into the bellows-type cover because of the likelihood of the clamping member becoming detached again from the bellows-type cover when one side of the clamping member enters the groove-shaped recess to abut at the bottom of the recess, in which case the opposite side would be able to slip out over the edge of the recess. Yieldable support members in the form of elastic lip-like projections extending toward one another which provide a temporary radially outer position of the two-tier arrangement with a completely safe retaining function to achieve the required integration are therefore necessary to assure an assembly of a bellows-type cover with integrated clamping member. The external surface 12 of the outer end of the bellows-type cover 10 is thereby inclined to form a rectilinearly obliquely upwardly extending flank to assist in centering and mounting the clamping ring in the groove-shaped recess of the self-retaining arrangement. The bellows-type cover 10 is made, for example, of Hytrell® and is to be fastened over a metallic axle stub by means of a shrinkable compression ring such as an "Oetiker" puzzle-type compression ring as disclosed in the two aforementioned U.S. patents. The compression ring has a nominal diameter of 88 mm. to be shrunk to a diametric dimension of 85 mm. which corresponds to the diametric dimension of the bottom 26 of the recess 11 . The width c of the radially outer portion of the groove-shaped recess 11 delimited by the side walls 21a and 21b is thereby 9.6 mm., the axial spacing e between the tips of the lip-like members 23a and 23b is 7.85 mm., the radius of curvature of the rounded-off portions 25a and 25b is 0.3 mm., the angle of the lower inclined surfaces 24a and 24b with respect to the radial direction is 45°, the width of the intersection of the surfaces 24a and 24b with the side walls of the recess 11 is 10 mm., the overall dimension g of the large end portion of the bellows-type cover is 15 mm., the depth d of the groove-shaped recess 20 is 3 mm., and the depth d' of the recess formed radially outwardly of by the upper support surfaces 22a and 22b is 1.5 mm. The overall thickness k of the end section 11 is 4.5 mm. while the radially inwardly extending circumferential projection 27 preferably centered with respect to the recess 11 , has a radially inward extension m of 0.5 mm., and has an axial length l of 5 mm. while the radii of curvature R1 are 0.5 mm. While I have shown and described only one embodiment in accordance with the present invention, it is understood that the same is not limited thereto but is susceptible of numerous changes and modifications as known to those skilled in the art. The two-tier arrangement may be used with any type of bellows made from any appropriate known elastic material whereby the yieldable support members are designed to provide the required elasticity considering the material used for the bellows-type cover and the need for yieldingness to permit a release of the temporary radially outer position of the integrated clamping member. Furthermore, the support members may be arranged in the groove-shaped recess so as to axially face one another pairwise but may also be arranged in staggered relationship so that one member on one side is followed staggered in the circumferential direction by the next member on the other side of the recess and so on. Additionally, the flank surface 12 need not be rectilinear but may also have a curved configuration of any appropriate shape. 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 claims.

Claims: A bellows-type cover member for an integratable clamping member to form a pre-assembled unit, comprising groove-shaped recess means (20) in the bellows-type cover member (10) for receiving a clamping member (40) , said recess means having a radially inward, circumferentially extending bottom surface (26) for engagement by said clamping member in the fully installed position thereof, and further means (23a, 23b) for holding said clamping member (40) in a pre-assembly position above said bottom surface, characterised in that said further means includes yieldable support members (23a, 23b) forming a temporary bottom at a level in said recess means (20) intermediate said bottom surface (26) and the radially outer boundaries of said recess means, for holding said clamping member (40) in the pre-assembly position within said recess means (20) such that it does not touch the bottom surface (26) of said recess means (20) . The cover member of claim 1, wherein said further means (23a, 23b) is operable to release the temporary bottom in the presence of radially inwardly directed forces to enable the clamping member (40) to move from said pre-assembly position to the fully installed position. The cover member of claim 1 or 2, wherein said further means includes at least one pair of yieldable support members (23a, 23b) at said level providing said temporary bottom. The cover member of claim 3, wherein several pairs of yieldable support members (23a, 23b) are provided along the circumference of said recess means (20) . The cover member of claim 3, wherein a respective pair of yieldable support members (23a, 23b) is formed by a pair of elastic lip-like projections extending from opposite side walls (21a, 21b) of said recess means (20) toward one another. The cover member of claim 5, wherein said lip-like projections (23a, 23b) are of approximately triangular shape in cross section and have a substantially axially extending top surface (22a, 22b) forming said temporary bottom, and wherein said top surface is preferably located at about half the depth of said recess means (20) . The cover member of any preceding claim, having an oblique external surface (12) slanting radially outwardly toward said recess means (20) to assist in mounting and centring a clamping member (40) during emplacement in said recess means (20) . The cover member of any preceding claim, including a clamping member (40) in said recess means (20) as an integrated part thereof. An assembly of a bellows-type cover means (10) with a pre-assembled integrated clamping member (40) adapted to be received in a groove-shaped recess means (20) provided in the bellows-type cover means, and further means (23a, 23b) providing a two-tier positioning of the clamping member (40) in which, in a first position, the clamping member is integrated with the bellows-type cover means (10) corresponding to the not-yet-tightened condition of the clamping member and, in a second position, the clamping member is in the installed tightened position, characterised in that said further means includes yieldable support members (23a, 23b) forming a temporary bottom at a level in said recess means (20) intermediate a bottom surface (26) and the radially outer boundaries of said recess means, for holding said clamping member (40) in the not-yet-tightened condition within said recess means (20) such that it does not touch the bottom surface (26) of said recess means (20) . The assembly of claim 9, wherein said further means (23a, 23b) is operable to provide a self-retaining action on the clamping member (40) in said first position at a substantially constant radial distance with respect to the bellows-type cover means (10) . The assembly of claim 9 or 10, wherein said further means is formed by axially extending projection means (23a, 23b) for non-removably retaining the clamping member (40) in said recess means (20) , and wherein said projection means (23a, 23b) are yieldable in the presence of tightening forces seeking to displace the clamping member from the first to the second position. The assembly of claim 11, wherein said projection means (23a, 23b) are approximately triangularly shaped with a top surface (22a, 22b) substantially parallel to the axis of the bellows-type cover means and an inclined surface (24a, 24b) extending from the tip of the projection means at an acute angle radially inwardly and toward the side surface (21a, 21b) of the recess means (20) . The assembly of any one of claims 9 to 12, wherein one side of the recess means (20) is formed by a part of the bellows-type cover means (10) having an inclined external surface (12) to facilitate installation of the clamping member (40) to be integrated in the bellows-type cover means.

Inventors: OETIKER HANS, OETIKER, HANS
Applicants: OETIKER HANS AG, HANS OETIKER AG
Application year: 1997
Main classification: F16D3
IPC codes: F16L57, F16J3, F16D3