Bicycle pedal with automatic attachment and detachment

A bicycle pedal with automatic attachment and detachment, the pedal having a body (2) rotating on a spindle (3) with a front stop (4) suitable for engaging with a mating stop surface (5) located on a cleat (6) fixed to the sole of the shoe of the user, and a retaining member (9) rotating about a hinge axis parallel to the pedal axis and able to be applied by an elastic return to the cleat to lock the cleat to the pedal. The elastic return means comprises a flexing element (B, 18), one end of which is housed in the pedal body, and the other end of which bears against the retaining member (9).

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a National Phase filing under 35 U.S.C. §371 of PCT/FR2008/000157 filed Feb. 8, 2008, which claims priority to Patent Application No. 0701017, filed in France on Feb. 13, 2007. The entire contents of each of the above-applications are incorporated herein by reference.

The invention relates to a bicycle pedal with automatic engagement and disengagement, of the kind which comprise a body mounted so that it can rotate on a spindle with:a frontal stop means able to collaborate with a mating stop surface provided on a cleat fixed under the sole of the user's shoe;a retaining member mounted to rotate about a pivot pin parallel to the pedal spindle, able to be pressed by an elastic return means against the cleat in order to attach the cleat to the pedal.

Automatic bicycle pedals are widely used by cyclists for all kinds of riding such as road racing, MTB riding, cycle touring and the like. The cyclist engages the cleat by placing it over the pedal and applying pressure with his foot, causing the cleat to attach to the pedal by the opening followed by the return against the cleat of the mobile retaining member.

Patents EP 1 377 496 B1 and FR 2 862 041 in the name of the Applicant Company disclose such pedals.

For disengagement and detachment the cyclist twists his foot which allows the cleat to be released automatically from the pedal through the opening of the retaining member.

Such automatic pedals are satisfactory but are relatively heavy and bulky. The component parts also take a relatively long time to assemble.

It is a key objective of the invention to provide an automatic pedal of the aforementioned type the weight of which is lower by comparison with the existing solutions, as is the size. Furthermore, it is desirable for the assembly of this pedal to be made quicker. It is also appropriate that the pedal design should remain robust and economical.

According to the invention, a bicycle pedal with automatic engagement and disengagement, of the kind defined hereinabove, comprises an elastic return means comprising a flex element immobilized at one end in the pedal body, the mean longitudinal direction of which is orthogonal to the pedal spindle and the other end of which rests against the retaining member, and is characterized in that:the retaining member consists of a bow in the overall shape of a U having two radially directed branches connected by a central part,and the flex element consists of a flex plate of which the end, other than the end immobilized in the body, rests against the bow.

For preference, the flex element rests against the lower edge of the central part of the bow.

The flex plate may be of rectangular shape or of trapezoidal shape with the long base housed in the pedal body and the short base resting against the retaining member.

The flex plate may be made of composite material, particularly with glass fibers or carbon fibers bound by a resin and directed orthogonal to the pedal spindle.

Advantageously, one end of the plate is immobilized in the pedal body by in-building achieved by clamping the end of the flex plate against the pedal body using a cap. The cap may be made of plastic stiffened by a metal bracket.

According to an alternative, the immobilized end of the plate is housed in the pedal body without being blocked therein, the top side of the end pressing against the body and friction between contacting surfaces holding the plate in place, a rod secured to the body extends transversely under the plate the underside of which rests against the rod, the other end of the plate resting, via its top face, against the retaining member such that the plate works in bending on three points.

At its end furthest from the in-building, the flex plate preferably rests against a transverse stop element mounted such that it can rotate on the retaining member of the pedal. This transverse stop element may be formed by a cylinder mounted such that it can rotate and comprising several flat faces at different radial distances from the geometric axis of the cylinder, rotating this element making it possible to modify the preload of the flex plate.

The retaining member may consist of a bow in the overall shape of a U having two radially directed branches connected by a transverse part. The bow is inscribed inside the rear of the pedal body which on each side comprises a downwardly projecting lug, the exterior face of one branch of the bow pressing against the interior face of the associated lug, each lug in its bottom part having a bore to accommodate a pivot pin passing through an orifice in the associated branch, the space between the pivot pins remaining clear.

The pedal advantageously comprises a pawl capable of keeping the retaining member in an open position, when the cleat is disengaged, against the action of a leaf spring, and of releasing this retaining member when the cleat is engaged; the pawl is produced in the form of a frame of which one transverse edge is engaged in a housing of the pedal body and constitutes the pivot pin for the pawl, the other end of the pawl resting against the retaining member. In order to limit the number of parts, the leaf spring of the pawl may be made as one piece with the pawl in plastic, the assembly being held above the flex element by clamping.

A ready-to-fit subassembly can be formed by engaging the leaf spring and the flex plate in an opening in the cap. This subassembly may also comprise the pawl, particularly when the pawl and the leaf spring are made as a single part.

According to an advantageous alternative form, the rear of the pedal body has no high transverse rear part that can serve to support the rear of the cleat, and a stop means is provided at the top rear of the bow to collaborate with a mating stop means provided in the lower part of a rear extension of the cleat, and to prevent attachment when the front snout of the cleat is not correctly engaged under the front lip of the pedal.

Reference is made to the drawings which show a bicycle pedal1with automatic engagement and disengagement. The pedal depicted in the example is intended to be mounted on the left side of the bicycle.

Hereinafter, the terms “front” and “rear” are to be understood as referring to a pedal in a horizontal position mounted on a bicycle and with reference to the normal direction of travel of the bicycle.

The pedal1comprises a body2able to rotate on a spindle3which projects from one side of the body in the form of a part3adesigned to have a screw thread so that it can be mounted at the end of a crank arm.

The pedal1comprises, on at least one face of the body, a frontal stop means4able to collaborate with a mating stop surface5provided on a cleat6fixed under the sole S of the user's shoe. The cleat6comprises a downwardly projecting part6aforming a cam. The stop5consists of the frontal face of the projection6a.

A lip7situated at the front of the pedal forms a return toward the pedal spindle3. A snout8provided at the front of the cleat6fits under the lip7.

A retaining member9is mounted such that it can rotate about a geometric axis of articulation A parallel to the pedal spindle. In the embodiment depicted, the axis A is situated to the rear of the pedal spindle3and lower down than this spindle when the pedal is horizontal. The retaining member9advantageously consists of a bow10in the overall shape of a U the concave face of which faces forward. This bow has two radially directed branches10aconnected by a part10bthat forms a cross member and is bounded by a cylindrical surface the geometric axis of which is the axis A.

As an alternative, the bow10could be situated in front of the spindle3, with its concave face facing rearward, the cam6awould then also face in the opposite direction.

The bow10is inscribed in the rear of the pedal body. The rear of the pedal body may consist of a contour2b, forming a cage member. As an alternative, this contour2bcould not exist. The contour2bcomprises, as visible inFIG. 6, on each side, a downwardly projecting lug11. The exterior face of one branch10apresses against the interior face of the associated lug11. Each lug11comprises, in its bottom part, a bore12(FIG. 5) opening at least onto its internal face. This bore12may be blind and closed at the end corresponding to the external face of the lug. As an alternative, the bore12may open onto the external face. The bores12of the two lugs11situated on each side of the pedal body have the same geometric axis.

Each branch10aof the bow comprises a through-orifice13(FIG. 5) capable of being positioned facing a corresponding bore12. The two orifices13have the same geometric axis. Once the branches10ahave been engaged between the lugs11, a pin14is fitted on each side, engaging it in the orifice13and in the bore12. The cylindrical pin14is force-fitted into the bore12. The two pins14housed in each of the lugs11are coaxial and allow the bow10to be mounted such that it can rotate between the lugs11. The lengths of the pins are limited to the sum of the thicknesses of the walls through which the pins14pass so that the space between the interior ends of the pins remains clear.

As an alternative, the lug11may comprise two cheeks separated by a housing accommodating the branch10abetween the cheeks, which cheeks each have a bore to accommodate the ends of the pin14. This clevis-block mounting of each pin then makes the articulation more rigid.

The part6aof the cleat that projects downward becomes housed behind a platform15of the pedal, with an underside16covering the region of the spindle3. The rear face of the platform15constitutes the frontal stop means4. The cam6acomprises, at its lower part, a rearwardly projecting snout17that can be covered by and attached to the bow10.

The elastic return means of the bow10comprises a flex element B the longitudinal mean direction of which is orthogonal to the pedal spindle3. One end B1of the flex element is housed in the pedal body2while the other end B2rests against the bow10, at the lower edge of the transverse part thereof, so as to exert a return force in the counterclockwise direction, according toFIGS. 1 and 2, about the geometric axis A. The flex element B passes above the geometric pivot axis A of the retaining member9. According to the alternative form ofFIGS. 1 and 2, the end B1is in-built, that is to say blocked, in the pedal body2.

The flex element B advantageously consists of a flex plate18. When this plate18is made of a homogeneous and isotropic material, for example of a metal notably stainless steel, this plate18is preferably configured in an isostress form. It is then substantially in the shape of an isosceles trapezium of which the long base is in-built into the body2and the short base rests against the bow10, as can be seen inFIG. 4.

The plate18may be made of composite material, in particular a material consisting of glass fibers or carbon fibers bound by a resin and directed essentially orthogonal to the spindle3. In such a case, the plate18is preferably of rectangular shape (FIG. 5) to limit the risks of delamination of the plate in the region of contact between its marginal edges and the bow10. However, when the fibers have crossed orientations, the isostress trapezium form may be envisioned. If need be, the flex plate may, in its region that is intended to be in-built, have a T-shaped profile, for example, guarding against any possible risk of slippage of the plate when stressed.

The plate18is in-built into the pedal body2using a cap19, for example made of plastic, of rectangular overall shape. The cap19has stiffened profiles and two holes20spaced apart parallel to the spindle3of the pedal. The holes20are designed to accept locking screws21which collaborate with tapped holes22provided in the pedal body. The holes22open into the underside of the pedal body.

The cap19is reinforced by a metal bracket23of which one flange, perpendicular to the plate in its in-built region, is fitted into a groove24of the cap19, while the other flange of the bracket projects forward and presses against the underside of the plate18. This second flange of the bracket23comprises two holes25which align with the holes22and20so that the screws21which flank the forward edge of the plate18can pass through them. An alternative design may be envisioned in which the metal bracket23is directly overmolded by the cap19.

In order to limit the concentration of stresses in the plate at the in-built edge, said in-built zone may consist of material that is very slightly soft in the region directly in contact with the plate, or the plate itself may consist of one or more layers of elastomer.

The underside of the pedal body2comprises, in its rear region, a surface that is set back in the vertical direction, bounded toward the front by a step26against which the front edge of the cap19rests.

The end of the flex plate18furthest from the in-building rests against the bow10via a transverse stop element mounted such that it can rotate on the bow10. The stop element27advantageously consists of an adjusting cylinder28having circular bearing surfaces at its two longitudinal ends, which bearing surfaces are housed in semicylindrical housings29that are open downward when the pedal is horizontal. The housings29are provided in side walls orthogonal to the pedal spindle3, these walls projecting toward the rear of the bow10. The spacing between the housings29, parallel to the axis A of the pedal, is less than the separation between the orifices13.

Between its circular end bearing surfaces, the cylinder28has flat facets28a,28b, parallel to the axis of the cylinder, and lying respectively at different radial distances from the geometric axis of this cylinder28. At least one of the end faces of the cylinder28comprises a diametral slot30(FIG. 5) so that the cylinder28can be turned in the housings29, for example using a screwdriver, in order to effect adjustment.

The end of the plate18rests against one of the facets of the cylinder28, for example against the facet28baccording toFIGS. 1 and 2. Because the cylinder28is mounted such that it can rotate in the housings29, as the bow10rotates, the end of the plate18may remain in contact across the entire expanse of the face28bby virtue of the rotating of the cylinder28in the housings29.

By altering the angular position of the cylinder28it is possible to cause the end of the plate18to rest against a different facet such as28awhich lies a different distance away from the axis of the cylinder, thus altering the stress in the plate18and therefore the elastic return force on the bow10. It is thus possible to adjust the return torque applied to the bow10.

Advantageously, the pedal also comprises a pawl31sensitive to whether the cleat6is off or on the pedal. The pawl31is designed to keep the retaining member9, formed by the bow10, in an open position illustrated inFIG. 1when the cleat is off, against the action of the elastic return means18.

The pawl31is produced in the form of a frame (seeFIG. 5) having a front cross member32of cylindrical shape constituting an articulation member housed in a housing33provided in the pedal body2and open downward. The housing33runs parallel to the pedal spindle. Branches extend backward from the ends of the cross member32to meet and form a substantially rectangular plate-like feature34. When the pawl31is in the raised position (FIG. 1), the plate-like feature34rests against the front edge of the cross member of the bow10to keep this bow in the open position.

The cross member32is held against the semicylindrical upper end wall of the housing33by a bar35of the cap19. Beneath the bar35, the cap has a transverse opening35a(FIG. 5) across which the flex plate18and a leaf spring36pass. The pawl31is returned to the raised position (FIG. 1) by the leaf spring36of which the front part is blocked in the pedal body2by being clamped between this body and the leaf18. The leaf36is curved and rests against the plate-like feature34via its end furthest from the pedal body2.

The pawl31is advantageously made of plastic. The leaf spring36may be made as a single piece with the pawl in plastic.

Means that provide positive blocking in a direction orthogonal to the spindle3may be provided between the flex plate18and the body2, notably in the form of mating pegs and housings, to supplement the stopping due to the clamping.

The cap19is able simultaneously to block the flex plate18and the leaf spring36by clamping, and to hold the pawl31in position.

The platform15of the pedal body is either overmolded or added on and held in place by an effective fixing means. The platform15is made of a material which may differ from that of the body2, preferably of a material that displays good performance in terms of resistance to wear and to hammering regions such as4of contact with the cleat6.

Toward the rear, the cleat6may have a soft region1bdesigned to press against the rear bridge2bof the pedal body in order to counter vertical float.

Assembly of the bow10of the flex plate18and of the pawl31is particularly simple and quick. The series of assembly operations indicated hereinbelow may be adapted to suit.

To begin with, the bow10is installed in the body2by positioning the branches10aof the bow between the lugs11of the pedal body and by placing the orifices13in register with the bores12. The pins14are then fitted, from the inside, into the orifices13and the bores12. An empty space remains between the pins14for the assembly of the next components. The bow10is pushed back into the raised position illustrated inFIG. 2and the cross member32of the pawl31can be fitted into the housing33. The cylinder28is placed in the housings29.

The cap19with the bracket23, the leaf spring36and the flex plate18are then fitted. To make the pedal easier to assembly, a ready-to-assemble subassembly is advantageously formed by fitting the leaf spring36and the flex plate18into the opening35aof the cap beforehand, while the bracket23is also fitted into the cap, beneath the plate18. When the leaf spring36is made as a single piece with the pawl31, the bar35finds itself clamped slightly between the cross member32and the leaf36, helping the subassembly, which then also comprises the pawl31, to stay together.

The leaf36and the plate18are then blocked against the pedal body2by the cross member23and the cap19, using the screws21.

The preload of the flex plate18is adjusted by orienting the cylinder28into the appropriate position.

The way in which the pedal works is recalled briefly hereinbelow.

When the cleat6,6ais not engaged, as illustrated inFIG. 1, the pawl31is in the raised position and its rear edge rests against the closed end of a housing provided in the front transverse edge of the bow10. This bow10is kept in the retreated open position.

When the cyclist wishes to attach the cleat6to the pedal1, he engages the front snout under the lip7and causes the cam6ato drop down into the empty space situated to the rear of the platform15and in front of the rear cage member2bof the pedal. Because the bow10is retreated, the cyclist encounters no appreciable resistance in pushing the cam6adown into this empty space and pushing the pawl31downward, because the force exerted by the elastic leaf36is relatively light.

The lowering of the pawl31by rotation in the clockwise direction about its cross member32releases the bow10which, under the action of the flex plate18, is returned in the counterclockwise direction about the pins14. The transverse branch of the bow10covers and fastens onto the rear snout17of the cleat6. The cleat6and the shoe to the underside of which this cleat is fixed are then attached to the pedal.

Disengagement or detachment of the cleat6is obtained by rotating the foot and the cleat6which causes the bow10to retreat until the snout17is released.

When the cleat6separates from the pedal1with the bow10in the open position, the pawl31is raised under the action of the elastic leaf36and its rear edge comes into line with the central branch10bof the bow10which is thus kept in the open position illustrated inFIG. 1.

The pedal according to the invention is of a simple and robust design allowing rapid assembly. Creating the elastic return means in the form of a flex plate18allows a reduction in weight, as does splitting the articulation down into two pins14of shorter length. It also makes it easy to house the pawl function thanks to a compact design.

FIG. 7shows an alternative form of embodiment of the pedal ofFIGS. 1 and 2. The only modification introduced relates to the mounting of the flex plate18which, instead of being in-built into the body2at its end B1, simply rests against this body. The other elements of the pedal ofFIG. 7are identical or similar to those ofFIGS. 1 and 2and are denoted by the same references without being described afresh.

The end B1of the plate18is housed in the body2without being blocked therein. The top face of the end B1rests against the body2and the friction between contacting surfaces holds the plate18in place. A rod37, preferably a cylindrical rod of circular cross section, is secured to the body2and extends transversely under the plate18, substantially in line with the rear wall of the housing33. The underside of the plate18rests against a generatrix of the rod37. The other end B2of the plate18rests, via its top face, against the stop element27.

The plate18operates in bending on three points, namely two ends points situated above the plate, and an intermediate point situated beneath.

The working of the pedal ofFIG. 7is similar to that explained previously.

FIGS. 8 and 9show an advantageous alternative form of embodiment of the pedal ofFIGS. 1-6. In this alternative form, the contour2bthat constitutes the rear part of the pedal body in the preceding figures is omitted.

The elements of the pedal ofFIGS. 8-9that are identical to or perform similar functions to elements already described in respect of the preceding figures are denoted by the same numerical references and are not described again.

According toFIG. 8, the branches10aof the bow, which are articulated to the pedal body by a pin14, are substantially horizontal and connected, at the rear, by a cross member10bperpendicular to the plane ofFIG. 8. Mid-way along the branches10a, the bow comprises a part10crising upward from the cross member10b. The part10c, which is substantially in the shape of an inverted L, constitutes the means of attachment of the rear snout17of the cleat6.

The front snout8of the cleat6butts via its upper face against the underside of the lip7to provide upward retention. The forward abutment of the cleat is still afforded by the collaboration between the rear surface4of the pedal platform, situated to the rear of the geometric axis of rotation of the pedal, and the frontal surface5of the cleat.

InFIGS. 8 and 9, the flex element B which constitutes the elastic return means for the bow10is not depicted. The same is true of the stop element27which is positioned in the housings29.

In the case illustrated inFIG. 9in which the snout8at the front of the cleat is not engaged under the lip7, the absence of the rear part2bof the pedal of the preceding figures allows the cleat6to catch on the bow10the cleat6. Such attachment of the cleat6in a poor position needs to be prevented.

To do this, a stop means38is provided at the top rear of the bow10to collaborate with a mating stop means39provided at the bottom part of a rear extension40of the cleat6when the snout8is not correctly engaged under the lip7. Collaboration between the stop means38and39prevents the cleat6from moving down and effacing the pawl31as this movement would cause the rear snout17of the cleat to catch on the part10cof the bow10.

The stop means38advantageously consists of a protrusion substantially of dihedral shape directed upward. The protrusion38is obtained by adding material to the top rear part of the part10cof the bow. The mating stop means39consists of a substantially horizontal flat underside of the rear extension40which is limited downward, in front of the stop39, by a concave surface41which can pass over the protrusion38when the front snout8is correctly engaged under the lip7.

Omitting the rear part2bresults in a space saving and makes the pedal more compact. Manufacture is simplified and the appearance is enhanced.

The way in which the pedal ofFIGS. 8-9works is similar to the working described in reference to the preceding figures.