Cleat bicycle pedal

Abstract: The above-mentioned invention relates a cleat-bicycle pedal connecting system comprising; a pedal (2); a pedal shaft (1) for rotatably supporting said pedal; a cleat rest (20) defined in said pedal for receiving said cleat; first and second hooks (4,5) mounted on said pedal and extending parallel to said pedal shaft, said hooks being located on opposite sides of said pedal shaft and having respective engaging portions engageable with said engaging portions of said cleat; a pivot shaft (7) mounted on said pedal and extending parallel to said pedal shaft, wherein said first book (5) is pivotable abut said pivot shaft between engaging and disengaging positions, wherein said cleat is engaged with said engaging portion of said first hook when said first hook is in its engaging position, and wherein said cleat is released from said engaging portion of said first hook when said first hook is in its disengaging positions; cam means for converting displacement of said cleat in a first direction into pivotal movement of said first hook toward its disengaging position, wherein said first direction is generally parallel to said pedal shaft; which is characterized by guide means for restricting the displacement of said cleat in said first direction, said guide means including a pair of guide elements (20c) mounted on said cleat rest, said guide elements being spaced apart from each other in said first direction, said guide elements having respective inclined guide faces (20d) which ore inclined upwardly away from each other.

Description: BACKGROUND OF THE INVENTION 1. FIELD OF THE INVENTION The present invention relates to a cleat-bicycle pedal. 2. DESCRIPTION OF THE PRIOR ART According to a known construction according to the preamble of the main claim (EP-A-0 146 454), the shoe is releasable from the pedal only by turning the shoe about an imaginary axis perpendicular or approximately perpendicular to the treads of the pedal, using the front end of the cleat as a pivotal point. With the known construction, therefore, the shoe may not be released from the pedal when, for example, the cyclist falls over to the ground and tilts the shoe sideways relativ to the pedal treads. Further, the rigid connection between the shoe and bicycle pedal, according to the prior art as noted above, applies a treading force of the cyclist to the pedal effectively and reliably. On the other hand, in the case of a mountain bike which runs rough terrains,such a connection transmits violent vibrations resulting from the roughness of the terrain to the cyclist's foot. The known connecting structure between the bicycle pedal and cleat includes engaging members attached to the pedal shaft for connection to the shoe, and the shoe rests on the pedal through the engaging members. Moreover, such engaging members are generally formed of a highly rigid material to assure a strong connection to the shoe. Thus, the vibrations due to the roughness of the terrain are transmitted directly to the cyclist's foot without being damped, thereby straining the cyclist's foot. Even in an ordinary run of the bicycle, the torsional force about the imaginary axis noted above may be applied to the shoe connected to the pedal body. When cornering on a mountain bike, for example, the cyclist may pedal the bike with only one foot in an unstable posture. To maintain his balance in such a condition, the cyclist turns the pedal body while applying a torsional force about the above-mentioned imaginary axis to the shoe connected to the pedal body. Further, when the cyclist pedals the bicycle without being seated on the saddle, the unstable posture could result in an inadvertent application of a torsional force about the imaginary axis to the shoe connected to the pedal body. According to the known structure noted above, the shoe could inadvertently disengage from the pedal body under the torsional force applied to the shoe connected to the pedal body. The cyclist faces a serious danger as a result of the shoe disengaging from the pedal body while the cyclist in such an unstable posture. To prevent the shoe from inadvertently disengaging from the pedal body, it is conceivable to set the torsional force for turning the shoe about the imaginary axis to a high level. However, such a measure would be inappropriate since the shoe would not readily be released from the pedal body in an emergency, such as when the cyclist falls over. Moreover, according to the known structure noted above, the shoe must be turned a great extent about the imaginary axis to become disengaged from the pedal body. In an emergency such as when the cyclist turns over, the shoe turned a small amount only results in re-engagement between the cleat and engaging members. The cyclist could be seriously injured with the shoe remaining caught with the pedal body. SUMMARY OF THE INVENTION The present invention has been made having regard to the state of the art noted above. It is an object of the invention, therefore, is to provide a connecting structure which releases the cleat with increased reliability when, for example, the cyclist falls over with his shoe inclined relative to the pedal. The object above is fulfilled, according to the present invention, by a cleat-bicycle pedal connecting system according to the main claim. An advantage of the present invention is to provide a connecting structure which reduces the strain of the cyclist's foot as well as a connecting structure which reliably connects the cleat to the pedal body during a normal run, and allows the cleat to be released from the pedal body in an emergency. According to an aspect of the invention, therefore, when running on a very rough terrain, part of the vibrations resulting from the rough ground are damped by the elasticity of the shoe bottom for transmission to the cyclist's foot. This connecting structure reduces the strain of the cyclist's foot, and greatly relieves the cyclist from fatigue particularly in rough road conditions or during a long distance run. A mountain bike must often run in rough ground conditions, and the cyclist must from time to time dismount the bike for crossing places impossible to ride through. The connecting structure of this invention is extremely useful for such situations in that the cleat is readily releasable from the pedal and that the cyclist is well protected from fatigue. The advantage noted hereinbefore is fulfilled, according to the present invention, by a connecting structure in which the pedal body includes rotation restrictors for contacting the cleat engaged by the hooks to restrain the cleat from rotating about an imaginary axis extending substantially along a direction of a pivotal movement of said hook, cam surfaces being defined on the rotation restrictors and/or on the cleat for moving the cleat away from the tread of the pedal body when the cleat engaged by the hooks is rotated about this imaginary axis. According to this aspect of the invention, the rotation restrictors basically restrain the cleat in the engaged state from rotating about the above imaginary axis. The cam surfaces defined on the rotation restrictors or on the cleat provide the option, as described hereunder, for the cleat to rotate or not to rotate about the imaginary axis, and hence the option for the cleat to disengage or not to disengage from the pedal body. During a normal run a great treading force is applied to the shoe to tread and turn the pedal body. This treading force is maintained during the normal run unless the shoe is intentionally lifted. Such treading force operates through the inclination of the cam surfaces to prevent the cleat from leaving the tread of the pedal body. That is, the cleat in the engaged state cannot rotate without moving away from the tread. As a result, the function of the cam surfaces is nullified and the rotation of the cleat above the above-mentioned imaginary axis is effectively restrained by the rotation restrictors. For this reason, even if a torsional force around the imaginary axis is applied to the cleat engaged by the pedal body, the cleat will not rotate about the imaginary axis to oscillate the hooks. Since the cleat remains engaged by the hooks, the cleat will never inadvertently become separated from the cleat. On the other hand, in an emergency such as when the cyclist falls over, the cleat may move away from the tread owing to the inclination of the cam surfaces since the treading force acting on the pedal body is at least temporarily removed. Thus, the rotation of the cleat about the above-mentioned imaginary axis is not in any way prevented by the presence of the rotation restrictors. The cleat, by its rotation, is disengageable from the hooks to separate from the pedal body. The cleat becomes disengaged from and moves away from the hooks, so that inadvertent reengagement between the cleat and hooks is positively avoided. The cleat is reliably separable from the pedal body for the same reason also when the cleat is rotated about the imaginary axis without a treading force applied intentionally. This promotes safety of the cyclist during a run while allowing the cyclist to turn the pedal body with full force despite an unstable posture such as in cornering. Other objects, features and advantages of the present invention will be apparent from the following description. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view showing a relationship between a cleat and a pedal, Figs. 2 and 3 are sectional views showing a relationship between the rear end of the cleat and a rotation restricting portion, Figs. 4 and 5 are schematic plan views showing the relationship between the rear end of the cleat and the rotation restricting portion; and Figs. 6 and 7 are views showing modifications made to the embodiment. As shown in Fig. 1, a cleat 30 includes a front engaging portion 30a and a rear engaging portion 30b for engagement with the hooks 4 and 5, respectively. The front engaging portion 30a has as first pressing edge a semicircular top 30c of a half cylinder projecting from a top surface thereof. The rear engaging portion 30b defines a second pressing edge 30f projecting upwardly. The front engaging portion 30a defines oblique contact portions 30d at opposite sides thereof for contacting forward movement stoppers 20a to be described hereunder. As shown in Figs. 1, 2 and 5, a cleat contact plate 20 formed of steel has right and left front corners bent upward. Each of these upwardly bent portions defines an oblique forward movement stopper 20a for contacting the contact portion 30d of the cleat 30, and a rotation restrictor 20b for contacting a side of the front engaging portion 30a. Further, the cleat contact plate 20 has right and left rear portions bent upward. Each of these upwardly bent portions defines a rear rotation restrictor 20c for contacting a side of the cleat 30. The two rear rotation restrictors 20c are inclined in a way to diverge upwardly away from a tread 2' of the pedal body 2, thereby defining cam surfaces 20d. When the cleat 30 is engaged by the hooks 4 and 5, as shown in Fig. 5, the front rotation restrictors 20b contact the opposite sides at the front end of the cleat 30 to prevent lateral movement of the front end of the cleat 30, and the forward movement stoppers 20a contact the oblique contact portions 30d of the cleat 30 to prevent forward movement of the cleat 30. The rear end of the cleat 30, by the action of the cam surfaces 20d, remains away frown the tread 2' of the pedal body 2 in the absence of a treading force. When a treading force is applied, the cam surfaces 20d act as the rear rotation restrictors 20c to prevent lateral movement of the rear end of the cleat 30. Consequently, the rotation of the cleat 30 about the imaginary axis extending substantially along a direction of a pivotal movement of said hook is prevented mainly when a treading force is applied. The way in which the connecting structure between the bicycle pedal body 2 and cleat 30 behaves will be described next. As shown in Fig. 1, when the cleat 30 attached to the shoe bottom S is pressed down on one of the treads 2' of the pedal body 2, the hooks 4 and 5 pivot in directions away from the pedal body 2 through contact with the inclined surfaces formed under the engaging portions 30a and 30b. Thereafter the hooks 4 and 5 pivot under the force of urging means, e.g. a spring 6 in directions toward the pedal body 2 and engage the engaging portions 30a and 30b, respectively. This completes the connection between the shoe and pedal body 2 as shown in Figs. 2, and 5. Since both of the hooks 4 and 5 pivot at this time, the treading action with respect to the pedal body 2 may be carried out in a direction substantially perpendicular to the tread 2' of the pedal body 2. In addition, the rear end of the cleat 30 is guided to a correct position by the cam surfaces 20d, so that the cyclist may pay little attention to the treading position relative to the pedal body 2. For disconnecting the shoe from the pedal body 2, the cleat may just be turned about the above-mentioned imaginary axis as shown in Fig 4, with no treading force applied to the rear end of the cleat 30. At this time, the front end of the cleat 30 is restrained from lateral movement by the front rotation restrictors 20b, so that this imaginary axis extends through a position adjacent the front rotation restrictors 20b. The rear or first hook 5 pivots rearwardly through a relative sliding movement between the second pressing edge 30f at the rear end of the cleat 30 and a cam surface 5b of the rear hook 5. The cleat 30 is thereby disengaged from the hooks 4 and 5 to complete disconnection between the shoe and the pedal body 2. In this way, the cyclist can positively select connection or disconnection of the cleat 30 or shoe to/from the pedal body 2 according to circumstances. In an emergency such as when the cyclist falls over, the treading force is at least temporarily removed from the pedal body 2. The cleat 30 may become disengaged from the pedal body 2 through a behavior similar to the intentional operation described above, thereby to secure safety of the cyclist. In this case, the rear end of the cleat 30 moves away from the tread 2' of the pedal body 2 under the guiding action of the cam surfaces 20d. The cleat 30 becomes disengaged from and moves away from the rear hook 5, so that inadvertent re-engagement between the cleat 30 and the rear hook 5 is positively avoided. In this embodiment, the rear rotation restrictors 20c and cam surfaces 20d are arranged to contact the cleat 30. However, these components may be adapted to contact the shoe bottom S. The pedal body 2 may include projections formed on each tread thereof and defining the rear rotation restrictors 20c acting as cam surfaces 20d, the rear rotation restrictors 20c being arranged to contact surfaces S1 in holes defined in the shoe bottom S (Fig. 6). The shoe bottom S is restrained from rotation about this imaginary axis by the contact between the rear rotation restrictors 20c and the surfaces S1. The shoe bottom S and cleat 30 are movable away from the tread 2' of the pedal body 2 with rotation about the said imaginary axis of the shoe bottom S. While the cam surfaces 20d are provided on the rear rotation restrictors 20c in the second embodiment and modification described above, the cam surfaces 20d may be formed on the cleat 30 or shoe bottom S only or may by formed on the cleat 30 or shoe bottom S as well as the rear rotation restrictors 20c. The rear rotation restrictors 20c may extend substantially perpendicular to the tread 2' of the pedal body 2, with the cleat 30 defining cam surfaces 20d at opposite sides at rear positions thereof which are inclined to converge downwardly. This construction corresponds to the second embodiment in function and effect. While the cam surfaces 20d are provided on the rear rotation restrictors 20c in the second embodiment, the cam surfaces 20d may be formed on the front rotation restrictors 20b only or may be formed on both the front rotation restrictors 20b and the rear rotation restrictors 20c. In the former the imaginary axis extending substantially along a direction of a pivotal movement of said hook is located rearwardly of the cleat 30, while in the latter the position of axis X variable with the way a couple of forces is applied to the cleat 30. In the former case, the relationship between the semicircular top 30c and the second pressing edge 3f and second pressed edge 5f may be reversed fore and aft from their relationship in the first embodiment. While, in this embodiment both of the hooks 4 and 5 are pivotable, only one e.g. the 1st hook 5 of them may be constructed pivotable and the other e.g. the second hook 4 formed integral with the pedal body. In this embodiment, the front and rear rotation restrictors 20b and 20c are distributed right and left of the pedal body 2. However, the rotation restrictors may be provided only at one front position and one rear position of the pedal body 2. Further, the rotation restrictors 20c and 20d may be provided centrally of the pedal body 2 instead of the two positions at the front and rear thereof. Also only one cam surface may be provided on the pedal body 2 instead of two. While, the forward movement stoppers 20a are provided in the forward portions of the pedal body 2, these may be provided centrally or rearwardly of the pedal body 2. The two forward movement stoppers 20a may be replaced by one forward movement stopper for contacting the entire front end of the cleat 30. A first cam mechanism is provided between each of the hooks 4 and 5 and the cleat 3, more particularly between each of the engaging elements 4a and 5a of the hooks 4 and 5 and each of the engaging portions 3a of the cleat. The cam mechanisms cause the hooks 4 and 5 to pivot toward the release positions when the cleat 3 is inclined about an imaginary axis extending substantially perpendicular to the tread of the pedal body 2. Each of the first cam mechanisms includes a second pressed edge 4f or 5f formed in a bent shape on a position of the hook 4 or 5 opposed to the cleat 3, and a second pressing edge 30f projecting from an upper position of the cleat 3 opposed to the hook 4 or 5 for slidable contact with the second pressed edge 4f or 5f. The second pressed edge 4f or 5f of the hook 4 or 5 lies in a path described by the second pressing edge 30f when the cleat 3 is turned (from the position shown in Fig. 4 to the position shown in Fig. 5). Further, a second mechanism is interconnected between each of the hooks 4 and 5 and the cleat 3 more particularly between each of the engaging elements 4a and 5a of the hooks 4 and 5 and each of the engaging portions 3a of the cleat (Fig. 5). The cam mechanisms cause the hooks 4 and 5 to pivot toward the release positions when the cleat 3 is inclined about an imaginary axis extending along the direction of pivotal movement of the hooks 4 and 5. Each of the second cam mechanisms includes a first pressed edge 4e or 5e (which is pressed when the shoe is released) formed linearly on a position of the hook 4 or 5 opposed to the cleat 3, and a first pressing edge 3e (which applies a pressing force when the shoe is released) formed in a bent shape (which may be curved though not shown) under a position of the cleat 3 opposed to the hook 4 or 5 for slidable contact with the first pressed edge 4e or 5e. As shown in Fig. 4 which is seen in the direction perpendicular to a tread face of the pedal body 2, the first pressed edge 4e or 5e and the first pressing edge 3e, when engaged, overlap each other.

Claims: A cleat-bicycle pedal connecting system comprising; a pedal (2); a pedal shaft (19 for rotably supporting said pedal; a cleat rest (20) defined in said pedal for receiving said cleat; first and second hooks(5,4) mounted on said pedal and extending parallel to said pedal shaft, said hooks being located on opposite sides of said pedal shaft and having respective engaging portions engageable with engaging portions of said cleat; a pivot shaft mounted on said pedal and extending parallel to said shaft, wherein at least said first hook(5) is pivotable about said pivot shaft between engaging and disengaging positions, wherein said cleat is engaged with said engaging portion of said first hook when said first hook(5) is in its engaging position, and wherein said cleat(30) is released from said engaging portion of said first hook (5) when said first hook is in its disengaging positions; urging means for urging said first hook(5) toward the engaging position; a first cam mechanism provided between said first hook (5) and said cleat (30) for causing the hook to pivot in the releasing direction during releasing movement about an imaginary axis extending substantially perpendicular to a tread (2') of said pedal body (2); characterized by guide means for restricting the releasing movement of said cleat (30) in said releasing direction, said guide means including a pair of guide elements (20c) mounted on said cleat rest (20), said guide elements being spaced apart from each other in said first direction, cam surfaces being provided between said guide elements and said cleat, said cam surfaces being inclined upwardly and away from each other which cause the cleat to rotate about an imaginary axis extending substantially along a direction of a pivotal movement of said hook and a second cam mechanism provided between said first hook (5) and said cleat (30) for causing the hook to pivot in a releasing direction during said rotation of said cleat. A cleat-bicycle pedal connecting system as claimed in claim 1 characterized in that the said second mechanism including a first pressed edge (4e,5e) defined on one of said hooks and opposed to said cleat (39), and a first pressing edge (3e) defined on said cleat (30) and opposed to said hook for slidable contact with said first pressed edge (4e,5e), and said first pressed edge and said first pressing edge overlapping each other in engaged condition as seen in a direction perpendicular to a tread (2') of said pedal body (2). A cleat-bicycle pedal connecting system as claimed in claim 1 characterized in that the said first mechanism including a second pressed edge (5f) defined on said hook and opposed to said cleat (30), and a second pressing edge (30c, 30f) defined on said cleat (30) and opposed to said hook for slidable contact with said second pressed edge, said second pressed edge (5f) of the hook (5) lying in a path described by said second pressing edge (30c,30f) of said cleat (30) when said cleat is in its releasing movement. A cleat-bicycle pedal connecting system as claimed in claim 2 or 3, charac-terized in that said first pressing edge (3e) and said second pressing edge (30c, 30f) comprise a common pressing edge formed on said cleat (30). A cleat-bicycle pedal connecting system as claimed in claim 4 characterized in that said first pressing edges are of cam type. A cleat-bicycle pedal connecting system as claimed in claim 1, characterized in that said cam surfaces being defined on said guide means or on said cleat (30) for the releasement of said cleat away from said tread (2') of said pedal body (2) when said cleat (30) engaged by said hooks (5,4) is in its releasing movements about said imaginay axis extending sustantially perpendicular to the tread of the pedal body. A cleat-bicycle pedal as claimed in claim 6, characterized in that said cam surfaces are defined on said guide means disposed rearwardly of said pedal body (2).

Inventors: NAGANO MASASHI, NAGANO, MASASHI
Applicants: SHIMANO KK, SHIMANO INC.
Application year: 1990
Main classification: B62M3
IPC codes: B62M3