WO1996033876A1

WO1996033876A1 - Cycle wheel rim using a connection sleeve and connection sleeve for such a rim

Info

Publication number: WO1996033876A1
Application number: PCT/FR1996/000509
Authority: WO
Inventors: Jean-Pierre Mercat; Alban Minville
Original assignee: Mavic S.A.
Priority date: 1995-04-28
Filing date: 1996-04-04
Publication date: 1996-10-31
Also published as: FR2733459B1; FR2733459A1

Abstract

The invention concerns a cycle wheel rim using a connection sleeve. The wheel rim comprises a profiled revolving section (1) having the shape of a hollow chamber and with two end faces (10a, 10b) interconnected end-to-end along a joining line (100) and rendered integral by a sleeve (5) inserted into the hollow chamber. The sleeve has at least two parts (50, 51) having bearing surfaces (50a, 51a) which exert internal pressure inside and against the walls of the hollow chamber. This pressure is generated by a spacer member (6) which moves the parts (50, 51) away from each other. The sleeve used enables play to be compensated and the ends of the wheel rim segment to be held tightly in an optimum manner. A wheel rim of this type has a highly resistant joint and this solution is particularly well-suited to so-called 'low-profile', lightweight wheel rims.

Description

Rim for cycle using a connection sleeve and connection sleeve for such a rim.

The invention relates to the manufacture and assembly of rims for cycles and relates more particularly to a rim using a connection sleeve. The invention also relates to the sleeve for the connection of such a rim.

The rims, and in particular those intended for cycles, are produced by an aluminum or bent aluminum alloy profile. In most cases, they are connected to the hub by spoke plies in order to constitute the cycle wheel. The profiles used are of different types, but generally have the shape of a U, comprising two lateral wings, the outer walls of which constitute the braking faces or flanks against which the brake pads are pressurized to ensure the desired braking.

Current rims are traditionally made in a manner known per se from a piece of profile of a determined length, which is curved and whose two ends are brought into contact and secured. The rigidity of the ring thus produced is of course a function of the quality of the material used to produce the initial profile and in particular its resistance, which is obtained according to a process known as by spinning or by extrusion of aluminum through a die having the dimensions and shapes of the section of the profile to be produced.

One of the essential problems of the construction of a rim is the achievement of the connection of the ends after the bending operation. There are different methods, but none is entirely satisfactory.

A very widespread method consists in assembling end to end the two ends of the piece of curved profile, then in carrying out a welding by sparking at the level of the junction line. A weld bead is obtained which must then be machined and then brushed. These operations are difficult to implement on fairly complex rim profiles. For machining, a cutter must move around the profile following the weld bead. Generally, a different cutter is used to remove the beads on the inner faces of the side fenders and in the rim tape, on which the tire must rest. These operations require the implementation of specific and suitable devices. Such a process is therefore expensive and is in fact only used by certain manufacturers for the manufacture of 'high-end' rims only.

As illustrated in FIG. 1, another method consists in connecting the two ends by two needles laterally spaced from one another, and which penetrate into lateral channels provided in the profile of the rim. To obtain a good resistance of the junction, the adjustment must be tight and it is therefore necessary to perfectly control the dimensional tolerances. In addition, the rim profiles obtained are heavier due to the excess material for each channel produced. This principle is more widespread but we can hardly consider using it for the manufacture of light rims intended for competition.

Another method consists in making the connection by sleeving of a hollow and prestressed tube inside the section of the rim profile. The tube has a shape substantially complementary to that of the internal section of the profile.

It is made by spinning in a light alloy usually based on aluminum. By this technique, it is difficult to correctly control the tolerances below 0.3 mm. The rim profile, for its part, is manufactured by spinning or by extrusion and the holding of tolerances is therefore of the same order of magnitude. Thus, the dispersion in the resistance values of the junction can be significant for a series of rims produced according to this method.

Another drawback is that the tube has a length greater than the length separating two lines of holes for laying the spokes. It is therefore necessary to mill holes in the tube at these drilling lines. This operation is difficult to carry out for very profiled rims intended for the use of the competition. It is also quite expensive.

Document US Pat. No. 4,938,540 relates to a rim and its manufacturing method which uses a connection by needles. To solve a sealing problem, an adhesive is used inside the channels in which the needles are inserted. This technique has the same drawbacks as those already mentioned for the principle of FIG. 1.

The present invention therefore proposes to solve the problems mentioned above by proposing a rim using an improved sleeve and the connection of which is made according to a more economical and more reliable process.

In particular, one of the objects of the invention is to avoid all the constraints linked to compliance with the dimensional tolerances of the profiles. On all profiles, the sleeve used allows backlash and optimal tightening of the ends between them of the rim segment.

Another object of the invention is to be able to shorten the sleeve while retaining sufficient resistance of the connection to the different torsional, tensile, compression or shear forces which the rim undergoes. The sleeve being shorter, any expensive machining operation is avoided.

Another object of the invention is to propose a solution which is particularly well suited for the production of so-called "profiled" and light rims intended for competition.

For this, the invention relates to a rim for cycle comprising a profile of revolution having in radial section the shape of a hollow box, with two end faces connected to each other, end to end, along a line junction, and secured by means of a sleeve inserted into the hollow box of the profile over a certain length of arc, on either side of the junction line. The sleeve comprises at least two parts having bearing surfaces which exert an internal pressure inside and against the walls of the hollow box, generated by relative spacing of said parts from each other by means of at least one spacer member. It is the spacer that ensures the adaptation of the sleeve, even in the event of dispersion of tolerances or differential expansion of the parts.

According to another characteristic, the spacing member is adjustable to allow the spacing of said parts to be varied between them. This freedom of adjustment allows control of the pressure exerted by the bearing surfaces against the walls of the box. This pressure can be adjusted to obtain a satisfactory tightening without exceeding the deformation limit of the rim casing.

According to another characteristic, the hollow box is delimited, inter alia, by two lateral sidewalls connected by a transverse bridge intended to support a tire; said bridge being provided with a light allowing access to the adjustment of the spacer member. At this point, the light is not visible when the tire is mounted on the rim. This therefore retains an impeccable external appearance. The interior of the rim protected by the tire cannot therefore be soiled by foreign bodies (water, mud, grease, etc.). Thus, there is also no need to add a plug.

According to another characteristic, the spacer member consists of a pressure screw which has a length of threaded rod which cooperates with a length of threaded bore of part of the sleeve, and one end of rod which presses on the other part of the sleeve. Using a pressure screw is particularly simple, economical and effective. The spacing forces generated by the screw can be significant for a low tightening torque.

According to another characteristic, the two lateral flanks gradually converge towards each other to form a lower base of internal section in the form of a "V" or "U". Likewise, the sleeve comprises a lower part having a bearing surface formed by two converging lateral faces connected by a lower line or edge having a general "V" or "U" shape, substantially complementary to the shape of the lower base. The problem encountered for such a so-called "profiled" rim for use in competition is that due to the particularly tapered shape of the rim base, a sleeve of traditional design offers low resistance to torsional forces in particular. With a sleeve of the invention whose shape, as defined, is adapted to the profile, the resistance to torsional forces is greatly improved. The surface in contact being also more important, one also increases the resistance to friction of the sleeve in the box.

According to another characteristic, the line or lower edge of the lower part of the sleeve forms an arc of radius less than the radius of the rim, in the absence of spacing force exerted by the pressure screw. The pressure stresses are thus distributed regularly along the sleeve during tightening by the fact that the sleeve bends. This characteristic allows a very significant improvement in the resistance of the connection.

According to another characteristic, the upper part of the sleeve has a lower rail which fits into the lower part in the shape of a "U" or "V, the upper ends of the wings of which are provided with lateral edges projecting inwards to prevent any vertical disengagement of the rail, thus making it easier to install the sleeve because the parts remain integral with one another.

The invention also relates to the sleeve suitable for connecting the ends of a rim for a cycle, which comprises at least two parts connected by at least one adjustable spacer which allows the continuous passage of a close state of said parts between they towards a determined state of separation.

More particularly, the spacing member consists of a pressure screw screwed into one of the parts and the end of the rod of which bears on the other part.

According to a first embodiment of the invention, the sleeve is formed of two separate parts and the parts are held integral by interlocking

Alternatively, the sleeve is formed in one piece, the parts of which are connected by elastic tabs.

Other characteristics and advantages of the invention will emerge from the description which will follow with regard to the appended drawings, which are given only by way of nonlimiting examples.

Figure 1 is a perspective view showing the connection of a rim according to a technique of the prior art.

Figure 2 is a simplified view of a wheel using a rim according to the invention.

FIG. 3 is a sectional view of the section of the rim at the level of the junction line, along the plane (l-l ') of the view in FIG. 2.

Figure 4 is a sectional view, similar to that of Figure 3, before tightening.

FIG. 5 is a sectional view along the plane (II, II ') of the view in FIG. 4.

FIG. 6 illustrates the operation of bending the rim. Figures 7 to 9 illustrate the sleeving step according to a first method of the invention.

Figures 10 to 12 illustrate a variant of the sleeving step.

Figure 13 is a longitudinal sectional view of a sleeve according to a variant of the invention.

FIG. 1 illustrates an example of a traditional rim (10) assembled by two needles (11, 12) spaced from one another and inserted into channels (21a, 21b, 22a, 22b) belonging to the profile of the rim.

The rim (1) according to the invention, illustrated in Figure 2, is intended to be fitted with spokes (2) and a central hub (3). The outer side of the rim also receives a tire (not shown). The rim, in itself, consists of a profile of revolution in the form of a large diameter ring, constructed from a curved segment having two ends (10a, 10b) whose faces are connected one to the other. the other and end to end along a junction line (100). The connection is made by a sleeve (5) of short arc length and which does not exceed the arc length separating two drilling lines in the rim of neighboring spokes (20a, 20b). Preferably, the sleeve is distributed, at equal length, on either side of the junction line (100), inside the casing of the rim.

Figure 3 shows a sectional section along the plane (ll ¹ ) of Figure 2; that is to say, passing through the junction line (100). It is a hollow box delimited by several walls including two lateral flanks (40, 41) elongated, converging and which join to form a lower base (30) of internal section in the shape of "V" or "U ". At the upper base (31), the sidewalls (40, 41) are connected by a concave transverse bridge (42) intended to support a tire (not shown).

The sidewalls (40, 41) extend beyond the transverse bridge by two lateral flanges (40a, 41a) which, with the transverse bridge (42), form a bowl of revolution perfectly adapted to withstand the inflation pressure of the tire and the maintain properly in place whatever the conditions.

Inside the hollow casing of the rim profile (1), as described, is the sleeve (5) according to the invention. It is formed by a first upper part (50), a second lower part (51) and a spacer (6), or pressure screw, which exerts a relative spacing of the two parts (50, 51) between them.

The first upper part (50) is traversed right through, along the general plane of symmetry (O, O ') of the rim, with a tapped bore (500). The spacer is, in turn, provided with a length of threaded rod (600) which cooperates with the length of threaded bore (500). The spacer ends with a rod end (61) which exerts support in a flat-bottom housing (510) formed in the interior bottom of the second lower part (51) of the sleeve.

The second lower part (51) has a bearing surface (51a) formed by two lateral faces connected by a line, or lower edge (51b). The bearing surface has a general "V" or "U" shape, substantially complementary to the internal shape of the lower base (30).

The upper part (50) has, for its part, a bearing surface (50a), of concave shape, substantially complementary to the shape of the internal surface of the transverse bridge (42). The upper part also has a lower rail (50b) which allows an interlocking in the lower part (51), the upper ends of the wings of which are provided with lateral flanges (51c) projecting inwards to prevent any vertical disengagement of the rail (50b). The realization of this fitting facilitates the fitting of the sleeve inside the rim box.

Figure 3 shows the sleeve in a separated position; the bearing surfaces (50a, 51a) exerting significant internal pressure against the walls of the rim casing (1).

Figure 4 shows the sleeve in a retracted position, before handling the pressure screw (6); the bearing surfaces not yet exerting significant pressure to allow sliding and adjustment of the sleeve inside the rim casing. In other words, the upper (50) and lower (51) parts are sufficiently close together by the pressure screw (6) to release the clearances necessary for the engagement of the sleeve. In particular, a significant clearance (7) is provided between the edge (51b) of the lower part and the bottom of the box (30a) by providing that the bottom of the box has a more pronounced curvature than the edge of the lower part. . This play (7) is accentuated by providing that the edge (51b) of the lower part (51) forms an arc of radius (R1) less than the radius (R2) of the bottom of the casing (30a) of the rim, in l absence of separation force exerted by the pressure screw, as shown in FIG. 5. By tightening the pressure screw (6) using a suitable tool (8), the sleeve bends, and a reduction in the clearance (7) is obtained and a better distribution of the pressure without deformation of the rim casing.

Under the same conditions, the radius (R3) formed by the bearing surface (50a) of the upper part (50), is greater than the radius (R4) of the internal surface (42a) of the transverse bridge (42); by reference, said radii being all measured in alignment with the plane of symmetry (O, O ').

Preferably, the pressure screw is provided with a head (62) connected to the threaded rod (600) by a weakening zone (63). A break is thus obtained from a determined torque value which is a function of the tightening value of the sleeve sought. The pressure screw allows a backlash and the tightening remains constant regardless of the tolerances of the parts.

By way of example, the value of the tensile strength of the ends (10a, 10b) can be measured in a tangential direction of the forces (T1, T2). For satisfactory tightening, the tensile strength value must be greater than 200 daN.

The rim according to the invention can be manufactured according to various methods which will be the subject of the description below.

The rim (1) is produced, in a known manner, from a segment of an aluminum or bent aluminum alloy profile. In a prior spinning or extrusion step, a bar having an initial profile is produced by the passage of the metal through a die (not shown). This bar is then cut into segments of sufficient length so that once bent; the desired rim diameter can be obtained. In a next step, illustrated in Figure 6, each segment is bent to form a circular ring and bring the ends of the segment end to end. The bending operation is carried out using a bender (9) which comprises drive rollers (90, 91), a guide roller (92) and a bending roller (93). Figure 6 illustrates the actual bending phase of the segment.

According to a first embodiment of the method of the invention, after the bending operation, each end (10a, 10b) of the segment is connected by inserting a sleeve (5), as described above, inside the hollow section.

The sleeve (5) is mounted in a state of minimal separation of the two parts (50, 51) to allow the ends (10a, 10b) to be brought together, until the faces of the ends come into contact, one against the other (Figures 7 and 8).

In this configuration, the pressure screw has a head (62) which passes through a lumen (420) of the transverse bridge (42). The light (420) is formed when the ends of the segment are brought together by the junction of two half-moons; each having been carried out on one end of the transverse bridge. The head (62) which projects out of the light during the connection operation, allows self-centering of the sleeve inside the hollow section, on either side of the junction line (100) .

After connection, the pressure screw (6) is tightened using a wrench or a screwdriver (8) adapted to the configuration of the head (62), until the parts are tightened by spacing ( 50, 51) between them of the sleeve.

Beyond a certain torque, the head (62) breaks below or at most at the level of the light (420) (FIG. 9). The subsequent operations of drilling the holes for the passage of the spokes, mounting the eyelets or other steps can then take place for the finishing of the rim, in a manner known per se.

A rim according to the invention can be connected according to a process a little different from that previously described. This variant is illustrated in FIGS. 10 to 12. First of all, the segment bending operation is carried out in the same manner as described and illustrated previously (FIG. 6).

Each end of the segment is then partially connected by inserting the sleeve in a configuration of minimum spacing of the two parts (50, 51). The ends (10a, 10b) remain spaced from each other by a certain distance at least equal to the width of the head of the pressure screw (6) (Figure 10).

Then, the pressure screw (6) is tightened using the tool (8) until the screw head breaks (Figure 11).

Finally, the connection operation is finished by forcibly bringing the ends (10a, 10b) closer together, until the faces of the ends meet one against the other (FIG. 12).

According to this method, it is not necessary to provide a light for access to the pressure screw.

The sleeve will preferably be made of resistant material but of low density, such as aluminum or aluminum alloy. One can also use other materials such as titanium or an alloy of aluminum, zinc, magnesium and copper called ZAMAC®.

Depending on the material used, the parts of the sleeve will be obtained by spinning as for aluminum or by pressure injection for ZAMAC®.

The materials cited have the advantage that they do not deteriorate during the subsequent anodizing and pickling operations commonly carried out on the finished rim. In some cases, however, it may be necessary to apply a varnish to certain alloys to avoid pollution of the anodizing baths.

The sleeve as described and shown in the previous examples is formed of two disjoint parts, fitted one inside the other. However, it is conceivable that the parts are connected together to form a single piece, without departing from the scope of the present invention. An example of such a variant is illustrated in FIG. 13. The sleeve has an upper (50) and lower (51) part connected by two elastic lateral connection tabs (52, 53). The spacing of the parts (50, 51) is permitted by means of the central pressure screw (6). On the contrary, when the pressure screw is loosened, the elasticity of the tabs allows the parts to come closer to each other to facilitate the adjustment of the sleeve to any type of profile according to differences in tolerances or expansions differentials due to the different materials used. Such a sleeve can be manufactured from a single metal part by injection, for example.

Of course, the embodiments described and shown, in particular the shape of the rim and of the sleeve constitute non-limiting solutions and one can imagine other equivalent solutions without going beyond the scope of the invention.

Claims

1- Cycle rim comprising a cycle rim comprising a profile of revolution (1) having in radial section the shape of a hollow box, with two end faces (10a, 10b) connected to each other, end to end, along a junction line (100), and secured by means of a sleeve (5) inserted into the hollow box of the profile over a certain arc length, on either side of the line junction (100), characterized in that the sleeve (5) comprises at least two parts (50, 51) having bearing surfaces (50a, 51a) which exert an internal pressure inside and against the walls of the hollow box (1), generated by relative spacing of said parts (50, 51) with one another by means of at least one spacer (6).

2- cycle rim according to claim 1, characterized in that the spacing member (6) is adjustable to allow the spacing of said parts (50, 51) to be varied.

3- Rim for cycle according to claim 2, characterized in that the hollow box (1) is delimited, inter alia, by two lateral flanks (40, 41) connected by a transverse bridge (42) intended to support a tire; said bridge being provided with a light (420) allowing access to the adjustment of the spacer member (6).

4- rim for cycle according to claim 3, characterized in that the spacer consists of a pressure screw (6) which has a length of threaded rod (600) which cooperates with a length of threaded bore (500) of a part (50) of the sleeve, and a rod end (61) which bears on the other part of the sleeve.

5- cycle rim according to claim 3 or 4, characterized in that the two lateral flanks (40, 41) gradually converge towards each other to form a lower base (30) of internal section in the shape of "V "or" U ".

6- Rim for cycle according to claim 5, characterized in that the sleeve comprises a lower part (51) having a bearing surface (51a) formed by two converging side faces connected by a line or lower edge (51b) having a general "V" or "U" shape, substantially complementary to the shape of the lower base (30).

7- Rim for cycle according to claim 6, characterized in that the line or lower edge (51b) of the lower part of the sleeve forms an arc of radius (R1) less than the radius (R2) of the bottom of the box (30a) of the rim, in the absence of spacing force exerted by the pressure screw (6).

8- Rim for cycle according to claim 6 or 7, characterized in that the upper part (50) of the sleeve has a lower rail (50b) which fits in the lower part (51) in the form of "U" or "V whose ends upper wings are provided with lateral flanges (51c) projecting inwards to prevent any vertical release of the rail (50b).

9- Rim for cycle according to any one of Claims 3 to 8, characterized in that the radius (R3) formed by the bearing surface (50a) of the upper part (50) is greater than the radius (R4) of the internal surface (42a) of the transverse bridge (42), in the absence of spacing force exerted by the pressure screw.

10- Sleeve for connecting the ends of a cycle rim, characterized in that it comprises at least two parts (50, 51) connected by at least one adjustable spacer (6) which allows continuous passage from a close state of said parts to one another towards a determined state of separation.

1 1 - Sleeve according to claim 10, characterized in that the spacer consists of a pressure screw (6) screwed into one of the parts and whose end of rod (61) exerts a support on the other part (51).

12- Sleeve according to claim 10 or 11, characterized in that it is formed of two separate parts and the parts (50, 51) are held integral by interlocking

13- Sleeve according to claim 10 or 11, characterized in that it is formed in one piece whose parts (50, 51) are connected by elastic tongues (52, 53).