# Patent

## Title
Bicycle pedal, cleat and bicycle pedal system

## Abstract

A bicycle pedal is detachable and engageable with a cleat that can be attached to shoes. The bicycle pedal basically includes a pedal shaft having a rotational center axis, a pedal main body and a clamp part. The pedal main body includes a first surface and a second surface. The second surface is on the opposite side of the first surface. The pedal main body is rotatably supported by the pedal shaft around the rotational center axis. The clamp part has at least three cleat clamping portions that detachably retain the cleat on at least the first surface of the pedal main body.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority to Japanese Patent Application No. 2014-087956, filed on Apr. 22, 2014 and Japanese Patent Application No. 2014-165920, filed on Aug. 18, 2014. The entire disclosures of Japanese Patent Application Nos. 2014-087956 and 2014-165920 are hereby incorporated herein by reference.
BACKGROUND
Field of the Invention
This invention generally relates to a bicycle pedal that is detachable and engageable with a cleat. This invention also relates a cleat that can be attached to shoe, and a bicycle pedal system comprising a cleat and a bicycle pedal.
Background Information
It is known to have a bicycle pedal system that uses cleats, in which a cleat can be attached to a shoe and a bicycle pedal detachably engages the cleat (see, for example, EP Patent Application Publication No. 0826586). A conventional bicycle pedal comprises a pedal shaft, a pedal main body that is rotatably supported by the pedal shaft and a clamp part having two cleat clamping portions disposed at an interval longitudinally along the traveling direction of the bicycle in the pedal main body. In this kind of pedal system, not only can the pedal be pushed down, but the pedal can also be pulled up, so that the pedal can be stably and efficiently operated.
SUMMARY
Generally, the present disclosure is directed to various features of a pedal and a cleat that is used with the pedal. In one feature, a pedal is disclosed that can retain a cleat even more stably than a conventional pedal system.
One object of the present invention is to provide a bicycle pedal, a cleat and a bicycle pedal system that are able to more stably retain a cleat to the pedal.
In view of the state of the known technology and in accordance with a first aspect of the present disclosure, a bicycle pedal is provided that is detachable and engageable with a cleat that can be attached to a shoe. The bicycle pedal comprises a pedal shaft having a rotational center axis, a pedal main body and a clamp part. The pedal main body comprises a first surface and a second surface that is on the opposite side of the first surface. The pedal main body is rotatably supported by the pedal shaft around the rotational center axis. The clamp part has at least three cleat clamping portions that detachably retain the cleat on at least the first surface of the pedal main body.
In this bicycle pedal, the cleat is detachably retained by three or more cleat clamping portions. For this reason, the gap in the three or more cleat clamping portions can be increased, and the pedal clamping portion can retain the cleat in a plane at three or more positions. As a result, the shoe to which the cleat is attached becomes less likely to be tilted, and the pedaling force of the rider can be efficiently transmitted to the pedal. With this, the pedal can be operated more stably and efficiently.
The clamp part can comprise a first cleat clamping portion, a second cleat clamping portion and a third cleat clamping portion. The third cleat clamping portion is disposed away from the second cleat clamping portion along the rotational center axis direction. The pedal shaft is disposed to extend between the first cleat clamping portion and the second cleat clamping portion. In this case, since the cleat is retained by the first cleat clamping portion to the third cleat clamping portion, which are provided in three locations, the interval for retaining the cleat can be made larger when compared to the conventional case in which the cleat is only retained in two locations. For this reason, the pedaling force of the rider can be even more efficiently transmitted, and the pedal can be more stably and efficiently operated.
The third cleat clamping portion can be disposed on a side having the second cleat clamping portion with respect to the pedal shaft. In this case, since the first cleat clamping portion, the second cleat clamping portion and the third cleat clamping portion are disposed sandwiching the pedal shaft, the interval for retaining the cleat can be increased in the longitudinal direction.
The third cleat clamping portion can be disposed between the first cleat clamping portion and the second cleat clamping portion as seen from the rotational center axis direction. In this case, since the third cleat clamping portion is disposed between the first cleat clamping portion and the second cleat clamping portion, the interval for retaining the cleat can be increased in the lateral direction.
The third cleat clamping portion can be disposed in a position that straddles the rotational center axis as seen from a direction that is perpendicular to a first surface. In this case, the third cleat clamping portion can be disposed in an intermediate position of the first cleat clamping portion and the second cleat clamping portion as seen from the rotational center axis by disposing the first cleat clamping portion and the second cleat clamping portion in a line symmetrically with respect to the rotational center axis. As a result, the interval for retaining the cleat can be increased in the lateral direction. With this, a shoe becomes less likely to be tilted in the lateral direction, and the pedaling force can be more efficiently transmitted to the bicycle pedal. For this reason, the pedal can be operated more stably and efficiently.
The pedal shaft can comprise a first end that is attached to a bicycle crank and a second end that is on an opposite side of the first end along the rotational center axis direction. The third cleat clamping portion can be disposed on a side having the second end with respect to the first and second cleat clamping portions. In this case, since the third cleat clamping portion can be offset from the first and second cleat clamping portions in the lateral direction, the cleat becomes even less likely to be tilted in the lateral direction, and the pedal can be operated more stably and efficiently.
The third cleat clamping portion can comprise a retaining portion that is engageable with the cleat, and a recess that faces the retaining portion. In this case, since the recess is formed in a portion that faces the retaining portion, clearance from the ground can be realized with this recess even if the bicycle is tilted when turning corners, etc.
The retaining portion can be disposed in a position that is offset from the first surface in a direction that intersects with the first surface. In this case, placing the cleat into the gap between the retaining portion and the first surface becomes easy.
The retaining portion can have a thickness that is less than the thickness of the pedal main body in the topmost portion. In this case, since the thickness of the retaining portion is less than the thickness of the topmost portion of the pedal main body, the cleat can be inserted into the thickness difference portion.
The retaining portion can comprise an engagement surface that is configured to contact with the cleat. The recess is formed in a portion that faces the engagement surface. In this case, since the cleat is in contact with the engagement surface at the gap between the retaining portion and the first surface, the cleat can be reliably retained.
The engagement surface can be disposed in a position that is offset from the first surface in a direction that intersects with the first surface. In this case, since the engagement surface is disposed in a position that is offset from the first surface in a direction that intersects with the first surface, a gap is formed between the engagement surface and the first surface on which the cleat is set. For this reason, the cleat can be easily put in contact with the engagement surface.
The third cleat clamping portion can also comprise a connecting portion that connects the retaining portion and the pedal main body. The connecting portion can be inclined with respect to the first surface and can extend along the rotational center axis direction. In this case, since the inclined connecting portion connects the retaining portion and the pedal main body, clearance from the ground can be realized by the connecting portion, even if the bicycle is tilted.
The connecting portion can also connect the two ends of the retaining portion and the pedal main body. In this case, the cleat can be inserted into the retaining portion between the connecting portion.
The third cleat clamping portion can also be integrally formed with the pedal main body. In this case, the rigidity of the third cleat clamping portion increases.
The third cleat clamping portion can also be formed between the retaining portion and the pedal main body and can comprise an opening into which the cleat is inserted. In this case, the cleat can be easily inserted into the retaining portion.
The third cleat clamping portion can also be non-rotatably coupled to the pedal main body. In this case, the rigidity of the third cleat clamping portion increases.
Either the first cleat clamping portion, the second cleat clamping portion, or the third cleat clamping portion can also be rotatably provided. In this case, since one of the three cleat clamping portions rotates, the cleat can be easily disengaged from the cleat clamping portion.
The first cleat clamping portion, the second cleat clamping portion, and the third cleat clamping portion can also be rotatably provided. In this case, since all of the cleat clamping portions rotate, the cleat can be more easily disengaged from the three cleat clamping portions.
The clamp part can also comprise three biasing members that bias the first cleat clamping portion, the second cleat clamping portion, and the third cleat clamping portion in a direction that retains the cleat. In this case, since the three cleat clamping portions are biased in a direction that retains the cleat within the biasing member, the cleat is less likely to be disengaged from the cleat clamping portion during pedaling, especially when pulling the pedal up.
The pedal main body can also comprise a first protrusion that protrudes from the first surface. In this case, the cleat becomes less likely to move in the longitudinal direction and the lateral direction due to the engagement of the cleat with the first protrusion.
The first protrusion can have a partially spherical or conical side surface. In this case, when the cleat approaches the first protrusion, the cleat will gradually move in a direction away from the first surface. Therefore, detaching the cleat will become easier.
The pedal main body can protrude from the first surface and can have a second protrusion that extends along the rotational center axis direction. In this case, detaching the cleat becomes easier by letting the cleat ride on the second protrusion.
The first protrusion can be provided in an intermediate portion of the second protrusion along the rotational center axis direction and can protrude with respect to the side surface of the second protrusion. In this case, the cleat will ride on the second protrusion by turning the cleat about the first protrusion, and the cleat will separate from the first surface. For this reason, the cleat can be easily detached from the cleat clamping portion with only a slight twisting operation of the shoes.
The pedal main body can also comprise an inclined surface that inclines from the second protrusion toward the first surface in a direction away from the pedal shaft. In this case, since an inclined surface is provided to the second protrusion, the cleat will gradually separate from the first surface due to the inclined surface when the shoe is turned about the first protrusion. For this reason, the cleat can be more easily detached from the cleat clamping portion.
The pedal shaft can also comprise a first end portion that is attached to the bicycle crank and a second end portion that is on the opposite side of the first end portion along the rotational center axis direction. The inclined surface can be provided to a side having the first end portion with respect to the first protrusion. In this case, since the inclined surface is provided to a side having the first end portion that is attached to the crank with respect to the first protrusion, the cleat will move in a direction away from the first surface due to the inclined surface by turning the cleat in either direction with respect to the first protrusion.
The first cleat clamping portion, the second cleat clamping portion, and the third cleat clamping portion can each comprise an engagement surface that is in contact with the cleat. The engagement surface can be positioned between the first surface and the endmost portion of the first protrusion in the direction that is perpendicular to the first surface. In this case, since the position of the retaining portion of the cleat will be in a position that is lower than the first protrusion with respect to the first surface, the pedals can be configured to be thinner.
The first cleat clamping portion, the second cleat clamping portion, and the third cleat clamping portion can also be disposed in the periphery of the pedal main body. In this case, the gap in each of the cleat clamping portions can be increased. As a result, since the three cleat clamping portions are disposed in the periphery of the pedal main body, the gaps in the three cleat clamping portions can be increased.
A cleat according to another aspect of the present invention detachably engages a clamp part that is attached to the pedal main body of the bicycle pedal. The cleat comprises a first engagement portion, a second engagement portion and a third engagement portion. The first engagement portion is configured to detachably engage the clamp part. The second engagement portion configured to detachably engage the clamp part in a position that is on the opposite side of the first engagement portion, with respect to the pedal shaft of the bicycle pedal. The third engagement portion detachably engages the clamp part in a position away from the second engagement portion along the rotational center axis direction of the pedal shaft.
Since the cleat engages the clamp part at three engagement portions, the gap in the three engagement portions can be increased, and the cleat can be retained in a plane at three positions. For this reason, the shoe to which the cleat is attached becomes less likely to be tilted, and the pedaling force of the rider can be efficiently transmitted to the pedal. With this, the pedal can be operated more stably and efficiently.
The third engagement portion can also engage the clamp part on a side having the second engagement portion with respect to the pedal shaft. In this case, since the first engagement portion, the second engagement portion and the third engagement portion are disposed sandwiching the pedal shaft, the gap for retaining the cleat can be increased in the longitudinal direction.
The third engagement portion can also engage the clamp part in a position between the first engagement portion and the second engagement portion as seen from the rotational center axis direction. In this case, since the third engagement portion is disposed between the first engagement portion and the second engagement portion, as seen from the rotational center axis direction, the interval for retaining the cleat can be increased in the lateral direction.
The cleat can be spherical or conical and can further comprise an abutting surface that abuts a part of the pedal main body. The abutting surface partially forms a spherical shape or a conical shape. In this case, since the cleat is in contact with a part of the main body at a spherical or a conical abutting surface, tilting the cleat with respect to the pedal main body when detaching the cleat from the clamp part becomes easy; therefore, detaching the cleat becomes easy.
The first engagement portion, the second engagement portion, and the third engagement portion can also be provided in the peripheral portion of the cleat. In this case, since the three engagement portions are disposed in the peripheral portion of the cleat, the interval of the three engagement portions can be increased.
A cleat according to yet another aspect of the present invention can be attached to a first surface that faces the shoe of the pedal main body of the bicycle pedal. The cleat comprises a first attaching portion, a second attaching portion, a connecting portion and an abutting surface. The first attaching portion is attached to the first surface. The second attaching portion is attached to the first surface on the opposite side of the first attaching portion, with respect to the pedal shaft of the bicycle pedal. The connecting portion is configured to be a connecting portion that connects the first attaching portion and the second attaching portion so that an interval is formed between the first attaching portion and the second attaching portion in which a part of the pedal main body is disposed; the abutting surface has a spherical or conical shape, and abuts a part of the pedal main body between the first attaching portion and the second attaching portion.
In these cleat, the first attaching portion and the second attaching portion are disposed sandwiching the pedal shaft, and the first attaching portion and the second attaching portion are connected by the connecting portion so that a part of the pedal main body is disposed. Additionally, the abutting surface that abuts a part of the pedal main body between the first attaching portion and the second attaching portion has a spherical or conical shape. For this reason, tilting the cleat with respect to the pedal main body when detaching the cleat from the clamp part becomes easy; therefore, detaching the cleat becomes easy.
The bicycle pedal system according to another aspect of the present invention comprises the above-described bicycle pedal and the above-described cleat.
According to the present invention, a bicycle pedal, a cleat, and a bicycle pedal system that are able to more stably retain a cleat to the pedal can be provided.
Also other objects, features, aspects and advantages of the disclosed pedal and the disclosed cleat will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses selected embodiments of the disclosed pedal and the disclosed cleat.



BRIEF DESCRIPTION OF THE DRAWINGS
Referring now to the attached drawings which form a part of this original disclosure.
FIG. 1 is a top perspective view of a bicycle pedal in accordance with a first embodiment.
FIG. 2 is a bottom plan view of the bicycle pedal illustrated in FIG. 1 in accordance with the first embodiment.
FIG. 3 is a cross-sectional view of the bicycle pedal illustrated in FIGS. 1 and 2 taken along the section line III-III in FIG. 2.
FIG. 4 is a top perspective view of a cleat that engages the pedal in accordance with the first embodiment.
FIG. 5 is a bottom perspective view of the cleat illustrated in FIG. 4.
FIG. 6 is a top perspective view of a bicycle pedal in accordance with a second embodiment.
FIG. 7 is a bottom plan view of the bicycle pedal illustrated in FIG. 6 in accordance with the second embodiment.
FIG. 8 is a cross-sectional view of the bicycle pedal illustrated in FIGS. 6 and 7 taken along the section line VIII-VIII of FIG. 7.
FIG. 9 is a top perspective view of a cleat that engages the pedal in accordance with the second embodiment.
FIG. 10 is a bottom plan view of the cleat illustrated in FIG. 9.
FIG. 11 is a top perspective view of a bicycle pedal in accordance with in accordance with a third embodiment.
FIG. 12 is a bottom plan view of the bicycle pedal illustrated in FIG. 11 in accordance with the third embodiment.
FIG. 13 is a top perspective view of a bicycle pedal in accordance with a first modification of the third embodiment.
FIG. 14 is a top plan view of the bicycle pedal illustrated in FIG. 13 in accordance with the first modification of the third embodiment.
FIG. 15 is a front elevational view of the bicycle pedal illustrated in FIGS. 13 and 14 in accordance with the first modification of the third embodiment.
FIG. 16 is a right side elevational view of the bicycle pedal illustrated in FIGS. 13 to 15 in accordance with the first modification of the third embodiment.
FIG. 17 is a cross-sectional view taken bicycle pedal illustrated in FIGS. 13 to 16 taken along the section line XVII in FIG. 14.



DETAILED DESCRIPTION OF EMBODIMENTS
Selected embodiments will now be explained with reference to the drawings. It will be apparent to those skilled in the bicycle field from this disclosure that the following descriptions of the embodiments are provided for illustration only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.
First Embodiment
Referring initially to FIG. 1, a bicycle pedal 10 is illustrated in accordance with a first embodiment. In FIGS. 1, 2 and 3, the bicycle pedal 10 (hereinafter referred to as pedal) is detachably engaged with a cleat 50 that is attached to a shoe. A bicycle pedal system 6 is configured by the pedal 10 and the cleat 50. Meanwhile, “front,” “rear,” “left,” “right,” “up,” “down” are synonymous with the terms “front,” “rear,” “left,” “right,” “up,” and “down,” as seen from a state in which the rider is sitting on the saddle while facing the handlebars (none of which is diagrammed).
Pedal
The pedal 10 comprises a pedal shaft 20 having a rotational center axis C1 (refer to FIG. 3), a pedal main body 22 that is rotatably supported by the pedal shaft 20, and a clamp part 24 having three or more cleat clamping portions that are provided to the pedal main body 22 and that retain the cleat 50.
As shown in FIG. 3, the pedal shaft 20 is housed in a shaft housing space 22c of the pedal main body 22, as mentioned below. The pedal shaft 20 rotatably supports the pedal main body 22 around the rotational center axis C1 that extends through a center of the pedal shaft 20 in a longitudinal direction via a pair of rolling bearings 26a and 26b. The pedal shaft comprises a first end portion 20a and a second end portion 20b. The first end portion 20a is attached to the bicycle crank 8. The second end portion 20b is on the opposite side of the first end portion 20a in the rotational center axis C1 direction. A male threaded portion 20c is provided to the second end portion 20b. The male threaded portion 20c is screwed into a screw hole 8a that is provided to the crank 8. The pedal shaft 20 is an axis with a real body, i.e., a shaft member, and the rotational center axis C1 is a virtual axis line. Meanwhile, in FIGS. 1 and 2, the drawing of the pedal shaft 20 has been omitted.
As shown in FIG. 2, the pedal main body 22 is a plate-like member made of metal or synthetic resin. The pedal main body 22 has a roughly isosceles triangular shape when seen from the bottom. The pedal main body 22 comprises a first surface 22a, a second surface 22b and a stepped cylindrical shaft housing space 22c. The first surface 22a faces the shoe. The second surface 22b is disposed on the opposite side of the first surface 22a. The stepped cylindrical shaft housing space 22c (refer to FIGS. 1 and 3) houses the pedal shaft 20.
As shown in FIG. 1, the pedal main body 22 comprises a first protrusion 32, a second protrusion 34, and at least one inclined surface 36 (two inclined surfaces 36 in this embodiment). The first protrusion 32 protrudes from the first surface 22a. The first protrusion 32 is disposed in a position that straddles the rotational center axis C1 when seen from a direction that is perpendicular to the first surface 22a. The first protrusion 32 is disposed on the cleat rotational axis C2. The cleat rotational axis C2 is a central axis of the rotation operation when detaching the cleat 50 from the pedal 10 and extends in a direction that is perpendicular to the first surface 22a. The first protrusion 32 comprises spherical or conical side surfaces 32a. In the first embodiment, the side surfaces 32a are partially conical. However, these surfaces can also have a partially spherical or a partially cylindrical surface shape.
The second protrusion 34 protrudes from the first surface 22a and extends in the rotational center axis C1 direction. The second protrusion 34 is disposed in a position that straddles the rotational center axis C1 when seen from a direction that is perpendicular to the first surface 22a. The protruding direction of the second protrusion 34 with respect to the first protrusion 32 is a direction that is parallel to the first surface 22a. Specifically, the second protrusion 34 protrudes from both sides of the rotational center axis C1 direction with respect to the first protrusion 32. In other words, the first protrusion 32 is provided to the center portion of the second protrusion 34 in the rotational center axis C1 direction. Additionally, the first protrusion 32 protrudes in a direction that is parallel to the first surface 22a with respect to the side surface 34a of the second protrusion 34.
At least one inclined surface 36 is inclined in a direction that gradually separates from the pedal shaft 20, from the second protrusion 34 toward the first surface 22a. The two ends of the inclined surface 36 are both connected to the top surface of the second protrusion 34 and the first surface 22a. In the first embodiment, the inclined surfaces 36 are provided on a side having the first end portion 20a and the second end portion 20b of the pedal shaft 20, with respect to the first protrusion 32. In other words, the inclined surfaces 36 are disposed on both sides of the first protrusion 32 in the rotational center axis C1 direction. Additionally, the inclined surfaces 36 are inclined in a direction that gradually separates from the pedal shaft 20 from both sides of the direction that is perpendicular to the rotational center axis C1 of the second protrusion 34 toward the first surface 22a. Therefore, in the first embodiment, four inclined surfaces 36 are provided sandwiching the first protrusion 32.
As shown in FIGS. 1 and 2, the clamp part 24 comprises three cleat clamping portions. In particular, the clamp part 24 comprises a first cleat clamping portion 30a, a second cleat clamping portion 30b, and a third cleat clamping portion 30c. The third cleat clamping portion 30c is disposed separate from the first and second cleat clamping portions 30a and 30b in the rotational center axis C1 direction. Additionally, the clamp part 24 comprises a first biasing member 38a, a second biasing member 38b (refer to FIG. 2) and a third biasing member 38c. The first biasing member 38a biases the first cleat clamping portion 30a in a direction that retains the cleat 50. The second biasing member 38b biases the second cleat clamping portion 30b in a direction that retains the cleat 50. The third biasing member 38c biases the third cleat clamping portion 30c in a direction that retains the cleat 50.
As shown in FIG. 2, the first cleat clamping portion 30a, the second cleat clamping portion 30b and the third cleat clamping portion 30c are disposed in the peripheral portion 22d of the pedal main body 22. Specifically, the first cleat clamping portion 30a, the second cleat clamping portion 30b and the third cleat clamping portion 30c are separately disposed in a first mounting recess 22e, a second mounting recess 22f and a third mounting recess 22g that are disposed in three corners of the pedal main body 22. The first mounting recess 22e to the third mounting recess 22g are formed to be recessed inwards in a roughly rectangular shape that extends through the first surface 22a and the second surface 22b. 
The first cleat clamping portion 30a and the second cleat clamping portion 30b are disposed sandwiching the pedal shaft 20 so that the pedal shaft 20 extends between them. Specifically, the first cleat clamping portion 30a and the second cleat clamping portion 30b are disposed so that they are in line symmetrically with respect to the rotational center axis C1. The third cleat clamping portion 30c is disposed between the first cleat clamping portion 30a and the second cleat clamping portion 30b when seen from the rotational center axis C1 direction. In the first embodiment, the third cleat clamping portion 30c is disposed in the intermediate position of the first cleat clamping portion 30a and the second cleat clamping portion 30b when seen from the rotational center axis C1 direction. That is, the third cleat clamping portion 30c is disposed on the rotational center axis C1. The third cleat clamping portion 30c is also disposed further on a side having the second end portion 20b than the first cleat clamping portion 30a or the second cleat clamping portion 30b. Therefore, the third cleat clamping portion 30c, the first cleat clamping portion 30a and the second cleat clamping portion 30b are disposed at an interval in the rotational center axis C1 direction (in the lateral direction). Meanwhile, the first cleat clamping portion 30a and the second cleat clamping portion 30b can be disposed on a side having the second end portion 20b, and the third cleat clamping portion 30c can be disposed on a side having the first end portion 20a. 
As shown in FIG. 2, the first cleat clamping portion 30a is rotatably provided around a first axis S1 by a first shaft member 40a that is disposed to the pedal main body 22 in the first mounting recess 22e along the first axis S1 direction. The first axis S1 extends in a direction that is parallel to the first surface 22a, as well as in a direction that intersects with a first straight line L1, which extends in the radial direction from the cleat rotational axis C2 toward the first cleat clamping portion 30a. Preferably, the first axis S1 extends in a direction that is essentially perpendicular to the first straight line L1.
The second cleat clamping portion 30b is rotatably provided around a second axis S2 by a second shaft member 40b that is disposed to the pedal main body 22 in the second mounting recess 22f along the second axis S2 direction. The second axis S2 extends in a direction that is parallel to the first surface 22a, as well as in a direction that intersects with a second straight line L2, which extends in the radial direction from the cleat rotational axis C2 toward the second cleat clamping portion 30b. Preferably, the second axis S2 extends in a direction that is essentially perpendicular to the second straight line L2. The second straight line L2 is disposed in a line symmetrical with the first straight line L1 with respect to the rotational center axis C1.
The third cleat clamping portion 30c is rotatably provided to the pedal main body 22 around a third axis S3 by a third shaft member 40c that is disposed in the third mounting recess 22g along the third axis S2 direction. The third axis S3 extends in a direction that is parallel to the first surface 22a, as well as in a direction that intersects with a third straight line L3, which extends in the radial direction from the cleat rotational axis C2 toward the third cleat clamping portion 30c. In the first embodiment, the third straight line L3 matches the rotational center axis C1 that passes through the cleat rotational axis C2. Preferably, the third straight line S3 extends in a direction that is essentially perpendicular with respect to the rotational center axis C1. Here, the first shaft member 40a, the second shaft member 40b, and the third shaft member 40c are a real bodies (the shaft members) in the same way as the pedal shaft 20, and are stopped by retaining rings that are not illustrated. The first axis S1, the second axis S2, and the third axis S3 are virtual axis lines in the same way as the rotational center axis C1.
As shown in FIGS. 1 and 2, the first cleat clamping portion 30a, the second cleat clamping portion 30b, and the third cleat clamping portion 30c each comprise a main body portion 30d and a retaining portion 30e. The retaining portions 30e retain the cleat 50. The main body portions 30d are rotatably supported by the pedal main body 22. The retaining portions 30e protrude from the main body portions 30d toward the first protrusion 32. The main body portions 30d are disposed with an interval that is able to retain the cleat 50 between the first surface 22a. Each of the retaining portions 30e of the first cleat clamping portion 30a, the second cleat clamping portion 30b, and the third cleat clamping portion 30c is biased in a direction toward the center (the first protrusion 32) of the pedal main body 22 by the first biasing member 38a, the second biasing member 38b, and the third biasing member 38c, respectively. A guide surface 30f that inclines toward the first surface 22a is formed in the retaining portion 30e. The guide surface 30f is provided to pivot the retaining portion 30e in the opening direction (counterclockwise in FIG. 3) against the biasing force of one of the first biasing member 38a to the third biasing member 38c, when one of the first cleat clamping portion 30a to the third cleat clamping portion 30c is pressed with the cleat 50.
As shown in FIG. 2, the first biasing member 38a is, for example, a torsion coil spring made of a metal spring wire with a circular cross section. In the first biasing member 38a, the first end portion 38d is locked to the first cleat clamping portion 30a, and the second end portion 38e is in contact with the distal end of a first screw member 42a for adjusting the spring force (the biasing force). The second end portion 38e of the first biasing member 38a is disposed in a groove that is formed on the second surface 22b toward the distal end of the first screw member 42a. The first screw member 42a is, for example, a hexagon socket set screw. The first screw member 42a is screwed in a screw hole that is disposed extending through the pedal main body 22. The distal end position of the first screw member 42a on a side having the second surface 22b can be adjusted by turning the first screw member 42a with a tool, such as a hexagonal wrench, from a side having the first surface 22a. The spring force (the biasing force) of the first biasing member 38a becomes stronger by approaching the distal end position of the first screw member 42a to the second surface 22b. 
The second biasing member 38b is a spring member made of metal wire with the same structure as the first biasing member 38a. In the second biasing member 38b, the first end portion 38d is locked to the second cleat clamping portion 30b, and the second end portion 38e is in contact with a second screw member 42b for adjusting the spring force (the biasing force). The second screw member 42b is a hexagon socket set screw like the first screw member 42a, and the protrusion amount on a side having the second surface 22b can be adjusted by a turning tool, such as a hexagonal wrench, from a side having the first surface 22a. If the protrusion amount of the second screw member 42b is increased, the spring force (the biasing force) of the second biasing member 38b becomes stronger.
The third biasing member 38c is, for example, a torsion coil spring made of a metal spring wire with a rectangular cross section. In the first embodiment, the first cleat clamping portion 30a and the second cleat clamping portion 30b are located adjacent on a side having the first end portion 20a of the pedal 10. In order to increase the retaining force on a side having the second end portion 20b for retaining the cleat 50 at one location of the third cleat clamping portion 30c, the biasing force of the third biasing member 38c is greater than the biasing force of the first biasing member 38a and the second biasing member 38b. However, the biasing members of the first biasing member 38a to the third biasing member 38c can be configured by those having the same biasing force. In the third biasing member 38c, the first end 38d is locked by the third cleat clamping portion 30c, and the second end 38e is locked by an adjustment member 42c for adjusting the spring force. The adjustment member 42 is, for example, a cylindrical member and is rotatably mounted to the second surface 22b around an axis that is parallel to the third axis S3. Formed on the outer peripheral surface of the adjustment member 42c are planar portions that cut away a part of the cylindrical surface at, for example, three locations in the circumferential direction; each of the planar portions is formed so that the distance to the center of the adjustment member 42 is different from each other. The second end portion 38e of the third biasing member 38c is selectively locked to the above-described plurality of planar portions of the adjustment member 42. The adjustment member 42c comprises a tool locking hole 42d to which tools such as a hexagonal wrench can be mounted. The planar portion that locks the second end portion 38e of the third biasing member 38c is changed by turning the adjustment member 42c by mounting a tool to this tool locking hole 42d, and the spring force (the biasing force) is changed.
Cleat
The cleat 50 is a plate-like member that is made of metal that has a roughly hexagonal shape. As shown in FIGS. 4 and 5, the cleat 50 comprises a first attaching portion 50a, a second attaching portion 50b, a connecting portion 50c, and a pair of abutting surfaces 50d that are attached to the first surface 22a of the pedal 10. The cleat 50 detachably engages the clamp part 24 that is attached to the pedal main body 22 of the pedal 10. The cleat 50 comprises a first engagement portion 52, a second engagement portion 54, and a third engagement portion 56, which detachably engages the clamp part 24.
The second attaching portion 50b is attached to the first surface 22a on the opposite side of the first attaching portion 50a with respect to the pedal shaft 20 of the pedal 10. The connecting portion 50c connects the first attaching portion 50a and the second attaching portion 50b to form a gap 60, in which a part of the pedal main body 22 is disposed between the first attaching portion 50a and the second attaching portion 50b. In the first embodiment, the connecting portion 50c is provided so that the first protrusion 32 and the second protrusion 34 as a part of the pedal main body 22 can be disposed in the gap 60.
The first engagement portion 52 is provided in the first attaching portion 50a and detachably engages the clamp part 24. The second engagement portion 54 detachably engages the clamp part 24 in a position that is on the opposite side of the first engagement portion 52, with respect to the pedal shaft 20 of the bicycle pedal 10. Therefore, the second engagement portion 54 is provided in the second attaching portion 50b. The third engagement portion 56 detachably engages the clamp part 24 in a position that is offset from the second engagement portion 54 along the rotational center axis C1 direction of the pedal shaft 20. In the first embodiment, the third engagement portion 56 can also engage the clamp part 24 in a position between the first engagement portion 52 and the second engagement portion 54, as seen from the rotational center axis C1 direction. In the first embodiment, the third engagement portion 56 is provided in the connecting portion 50c. 
Specifically, the first engagement portion 52 engages the first cleat clamping portion 30a of the clamp part 24. The second engagement portion 54 engages the second cleat clamping portion 30b of the clamp part 24. The third engagement portion 56 engages the third cleat clamping portion 30c of the clamp part 24. The first engagement portion 52, the second engagement portion 54, and the third engagement portion 56 are provided in the peripheral portion 50e of the cleat 50. The first engagement portion 52, the second engagement portion 54, and the third engagement portion 56 all comprise an attaching recess 58 that is formed recessed from the peripheral portion 50e of the cleat 50. The attaching recess 58 is formed to be recessed in a flat isosceles trapezoid shape in a plan view. The thickness of the first engagement portion 52, the second engagement portion 54, and the third engagement portion 56 on a side having the peripheral portion 50e of the cleat 50 is slightly smaller than the gap between the retaining portion 30e of the clamp part 24 and the first surface 22a. 
A pair of abutting surfaces 50d (refer to FIG. 5) are provided so that they abut a part of the pedal main body 22. The cleat 50 comprises a pair of long holes 62 for attaching, which are for attaching the cleat 50 to the shoes with a bolt member (not diagrammed). The abutting surfaces 50d have partially spherical, conical, or cylindrical shapes. In the first embodiment, the abutting surfaces 50d are partially conical shaped and abut the side surfaces 32a of the first protrusion 32 as a part of the pedal main body 22. The abutting surfaces 50d each have a side surface shape that corresponds to the side surfaces 32a of the first protrusion 32. The distal end portion of the pair of abutting surfaces 50d that are disposed opposing each other is formed in a flat V-shape. Meanwhile, in the case that the first protrusion 32 has a conical shape or a spherical shape, the abutting surface can have a cylindrical shape.
Attaching and Detaching Operation of the Cleat
In a bicycle pedal system 6 configured in this way, when attaching a shoe to the pedal 10, the shoe is disposed on the first surface 22a of the pedal main body 22 of the pedal 10 in a state in which the cleat 50 is attached to the shoe by a bolt member that is not diagrammed. Then, the first engagement portion 52 and the second engagement portion 54 are engaged with the first cleat clamping portion 30a and the second cleat clamping portion 30b. In this state, if the outside of the shoe (a side having the second end portion 20b of the pedal shaft 20) is strongly stepped into the pedal 10, the retaining portion 30e will open due to the action of the guide surface 30f of the retaining portion 30e of the third cleat clamping portion 30c, and the third engagement portion 56 of the cleat 50 will be clamped by the third cleat clamping portion 30c. In a state in which the cleat 50 is retained by the clamp part 24, the pair of abutting surfaces 50d will be contact with and will be disposed to the side surfaces 32a of the first protrusion 32. At this time, the cleat 50 will engage the pedal 10 at three positions, and the gap between the first cleat clamping portion 30a and the third cleat clamping portion 30c, as well as the gap between the second cleat clamping portion 30b and the third cleat clamping portion 30c, can be made larger than the width of a conventional lever member that engages the pedal at one position in the rear. For this reason, the cleat 50 can be retained to the pedal 10 more stably than with the prior art. Additionally, the shoe to which the cleat 50 is attached becomes less likely to be tilted, and the pedaling force of the rider can be efficiently transmitted to the pedal 10. With this, the pedal 10 can be operated more stably and efficiently. Meanwhile, as the attaching and detaching operation of the cleat 50, first engaging the third engagement portion 56 to the third cleat clamping portion 30c and then engaging the first engagement portion 52 and the second engagement portion 54 simultaneously to the first cleat clamping portion 30a and the second cleat clamping portion 30b by stepping onto the inner side of the pedal 10 is also possible.
When detaching the shoe from the pedal 10, the heel side of the shoe is slightly twisted outside. Then, since the abutting surfaces 50d abuts the side surfaces 32a of the first protrusion 32, the shoe rotates about the cleat rotational axis C2. At this time, the abutting surfaces 50d slides along the side surfaces 32a. When the shoe rotates, the corner of the opposing surface of the first attaching portion 50a and the second attaching portion 50b of the cleat 50 will ride on the inclined surface 36. With this, the cleat 50 is separated from the first surface 22a of the pedal 10, and the third cleat clamping portion 30c will be pushed up from the first cleat clamping portion 30a to be opened. As a result, the cleat 50 will be detached from the pedal 10, and the shoe can be detached from the pedal 10. By making the side surface shapes of the abutting surfaces 50d and the side surfaces 32a partially spherical or conical, when the cleat 50 start to separate from the first surface 22a, the cleat 50 is moved in a direction that intersects with the cleat rotational axis C2 along the side surfaces 32a, and the cleat 50 can be easily detached from the pedal 10.
Second Embodiment
In FIGS. 6, 7 and 8, the pedal 110 according to the second embodiment of the present invention is detachably engaged with a cleat 150 that are attached to shoes. A bicycle pedal system 106 is configured by the pedal 110 and the cleat 150.
Pedal
The pedal 110 comprises a pedal shaft 120 (refer to FIG. 8) having a rotational center axis C1, a pedal main body 122 that is rotatably supported by the pedal shaft 120, and a clamp part 124 that is provided to the pedal main body 122 and that has three or more cleat clamping portions that retain the cleat 150.
As shown in FIG. 8, the pedal shaft 120 is housed in the shaft housing space 122c of the pedal main body 122, as mentioned below, in the same way as in the first embodiment. The pedal shaft 120 rotatably supports the pedal main body 122 around the rotational center axis C1 that passes through the center of the pedal shaft 20 and that extends in the longitudinal direction via a pair of rolling bearings 126a and 126b. The pedal shaft 120 comprises a first end portion 120a that is attached to the bicycle crank 8 and a second end portion 120b that is on the opposite side of the first end portion 120a in the rotational center axis C1 direction. A male threaded portion 20c, which is screwed into a screw hole 8a that is provided to the crank 8, is provided to the second end portion 120b. The pedal shaft 120 is an axis with a real body, i.e., a shaft member, and the rotational center axis C1 is a virtual axis line. Meanwhile, in FIGS. 6 and 7, a drawing of the pedal shaft 120 has been omitted.
As shown in FIG. 7, the pedal main body 122 is a plate-like member made of metal or synthetic resin and has a roughly heart shape when seen from the rear. The pedal main body 122 comprises a first surface 122a that faces the shoe, a second surface 122b that is on the opposite side of the first surface 122a, and a stepped cylindrical shaft housing space 122c (refer to FIGS. 6 and 8) in which the pedal shaft 20 is housed.
As shown in FIG. 6, the pedal main body 122 comprises a first protrusion 132, a second protrusion 134, and at least one inclined surface 136 (two in the illustrated embodiment. The first protrusion 132 protrudes from the first surface 122a. The first protrusion 132 is disposed in a position that straddles the rotational center axis C1 when seen from a direction that is perpendicular to the first surface 122a. The first protrusion 132 is disposed on the cleat rotational axis C2. The cleat rotational axis C2 is a central axis of the rotation operation when detaching the cleat 150 from the pedal 110, and this axis extends in a direction that is perpendicular to the first surface 122a. The first protrusion 132 comprises a pair of partially spherical or conical side surfaces 132a. In the second embodiment as well, the side surfaces 132a are partially conical. However, the side surfaces 132a can also have a partial spherical or a partial cylindrical surface shape.
The second protrusion 134 protrudes from the first surface 122a and extends in the rotational center axis C1 direction. The second protrusion 134 is disposed in a position that straddles the rotational center axis C1 when seen from a direction that is perpendicular to the first surface 122a. The protruding direction of the second protrusion 134, with respect to the first protrusion 132, is a direction that is parallel to the first surface 122a. Specifically, the second protrusion 134 protrudes on both sides of the rotational center axis C1 direction with respect to the first protrusion 132. In other words, the first protrusion 132 is provided to the center portion of the second protrusion 134 in the rotational center axis C1 direction. Additionally, the first protrusion 132 protrudes in a direction that is parallel to the first surface 122a with respect to the side surface 134a of the second protrusion 134.
At least one inclined surface 136 is inclined in a direction that gradually separates from the pedal shaft 120, from the second protrusion 134 toward the first surface 122a. The two ends of the inclined surface 136 are each connected to the top surface of the second protrusion 34 and the first surface 122a. In the second embodiment, the inclined surfaces 136 are provided on a side having the first end portion 20a of the pedal shaft 20, with respect to the first protrusion 132; that is, the inclined surfaces 136 are disposed on one side of the first protrusion 132 in the rotational center axis C1 direction. Additionally, the inclined surfaces 136 are inclined in a direction that gradually separates from the pedal shaft 120 from both sides of the direction that is perpendicular to the rotational center axis C1 of the second protrusion 134 toward the first surface 122a. Therefore, in the second embodiment, two inclined surfaces 136 are provided sandwiching the second protrusion 134.
As shown in FIGS. 6 and 7, the clamp part 124 comprises three cleat clamping portions, a first cleat clamping portion 130a, a second cleat clamping portion 130b, and a third cleat clamping portion 130c that is disposed separate from the second cleat clamping portion 130b in the rotational center axis C1 direction. Additionally, the clamp part 124 comprises a first biasing member 138a (refer to FIG. 7), a second biasing member 138b, and a third biasing member 138c. The first biasing member 138a biases the first cleat clamping portion 130a in a direction that retains the cleat 150. The second biasing member 138b biases the second cleat clamping portion 130b in a direction that retains the cleat 150. The third biasing member 138c biases the third cleat clamping portion 130c in a direction that retains the cleat 150.
As shown in FIG. 7, the first cleat clamping portion 130a, the second cleat clamping portion 130b, and the third cleat clamping portion 130c are disposed in the peripheral portion 122d of the pedal main body 122. Specifically, the second cleat clamping portion 130b, the third cleat clamping portion 130c, and the first cleat clamping portion 130a are separately disposed in a second mounting recess 122f and a third mounting recess 122g that are disposed on both sides of a heart-shaped recess of the pedal main body 122, as well as in a first mounting recess 122e that is disposed in the distal end portion that faces the heart-shaped recess, respectively. The first mounting recess 122e to the third mounting recess 122g are formed to be recessed inwards in a roughly rectangular shape extending through the first surface 122a and the second surface 122b. 
The first cleat clamping portion 130a and the second cleat clamping portion 130b are disposed sandwiching the pedal shaft 120 so that the pedal shaft 120 extends between them. The third cleat clamping portion 130c is disposed on a side having the second cleat clamping portion 130b with respect to the pedal shaft 120. In the second embodiment, the third cleat clamping portion 130c is disposed on a side having the second end portion 120b of the pedal shaft 120 of the second cleat clamping portion 130b. Therefore, the first cleat clamping portion 130a, the second cleat clamping portion 130b and the third cleat clamping portion 130c are disposed at an interval in a direction that is perpendicular to the rotational center axis C1 direction (the longitudinal direction). Meanwhile, the third cleat clamping portion 130c can be disposed on a side having the second end portion 120b, and the second cleat clamping portion 130b can be disposed on a side having the first end portion 120a. 
As shown in FIG. 7, the first cleat clamping portion 130a is rotatably provided around a first axis S1 by a first shaft member 140a that is disposed to the pedal main body 122 along the first axis S1 direction. The first axis S1 extends in a direction that is parallel to the first surface 122a, as well as in a direction that intersects with a first straight line L1, which extends in the radial direction from the cleat rotational axis C2 toward the first cleat clamping portion 130a. Preferably, the first axis S1 extends in a direction that is essentially parallel to the rotational center axis C1 and that is essentially perpendicular with respect to the first straight line L1.
The second cleat clamping portion 130b is rotatably provided around a second axis S2 by a second shaft member 140b that is disposed to the pedal main body 122 along the second axis S2 direction. The second axis S2 extends in a direction that is parallel to the first surface 122a, as well as in a direction that intersects with a second straight line L2, which extends in the radial direction from the cleat rotational axis C2 toward the second cleat clamping portion 130b. Preferably, the second axis S2 extends in a direction that is essentially perpendicular to the second straight line L2.
The third cleat clamping portion 130c is rotatably provided around a third axis S3 by a third shaft member 140c that is disposed to the pedal main body 122 along the third axis S3 direction. The third axis S3 extends in a direction that is parallel to the first surface 122a, as well as in a direction that intersects with a third straight line L3, which extends in the radial direction from the cleat rotational axis C2 toward the third cleat clamping portion 130c. In the second embodiment, the third straight line L3 is disposed in a position that is in line symmetrically with the second straight line L2, with respect to the rotational center axis C1 that passes through the cleat rotational axis C2. Preferably, the third axis S3 extends in a direction that is essentially perpendicular to the third straight line L3. Here, the first shaft member 140a, the second shaft member 140b, and the third shaft member 140c are axes with a real body (the shaft member) in the same way as the pedal shaft 120, and they are fixed to the pedal main body 122 by a male threaded portion that is formed in the distal end. The first axis S1, the second axis S2, and the third axis S3 are virtual axis lines in the same way as the rotational center axis C1.
As shown in FIGS. 6 and 7, the first cleat clamping portion 130a, the second cleat clamping portion 130b, and the third cleat clamping portion 130c all comprise a main body portion 130d and a retaining portion 130e that retains the cleat 150. The main body portion 130d is rotatably supported by the pedal main body 122. The retaining portion 130e protrudes from the main body portion 130d toward the first protrusion 132 and is disposed with an interval that is able to retain the cleat 150 between the first surface 122a. All of the retaining portions 130e of the first cleat clamping portion 130a, the second cleat clamping portion 130b, and the third cleat clamping portion 130c are biased in a direction toward the center (the first protrusion 32) of the pedal main body 122 by the first biasing member 138a, the second biasing member 138b, and the third biasing member 138c, respectively. A guide surface 130f that inclines toward the first surface 122a is formed in the retaining portion 130e. The guide surface 130f is provided to pivot the retaining portion 130e in the opening direction against the biasing force of one of the first biasing member 138a to the third biasing member 138c when one of the first cleat clamping portion 130a to the third cleat clamping portion 130c has been pressed with the cleat 150.
As shown in FIG. 7, the first biasing member 138a is, for example, a torsion coil spring made of a metal spring wire with a circular cross section. In the first biasing member 138a, the first end portion 138d is locked to the first cleat clamping portion 130a, and the second end portion 138e is in contact with the distal end of a first screw member 142a for adjusting the spring force (the biasing force). The second end portion 138e of the first biasing member 138a is disposed in a groove that is formed on the second surface 122b toward the distal end of the first screw member 142a. The first screw member 142a is, for example, a hexagon socket set screw that is screwed into a screw hole that is disposed extending through the pedal main body 122. The distal end position of the first screw member 142a on a side having the second surface 122b can be adjusted by turning the first screw member 142a with a tool, such as a hexagonal wrench, from a side having the first surface 122a. The spring force (the biasing force) of the first biasing member 138a becomes stronger as the distal end position of the first screw member 142a approaches the second surface 122b. 
The second biasing member 138b is a spring member made of metal wire with the same structure as the first biasing member 38a. In the second biasing member 138b, the first end portion 138d is locked to the second cleat clamping portion 130b, and the second end portion 138e is in contact with a second screw member 142b for adjusting the spring force (the biasing force). The second screw member 142b is a hexagon socket set screw like the first screw member 142a, and the distal end position on a side having the second surface 122b can be adjusted by using of a turning tool, such as a hexagonal wrench, from a side having the first surface 122a. The spring force (the biasing force) of the second biasing member 138b becomes stronger as the distal end position of the second screw member 142b approaches the second surface 122b. 
The third biasing member 38c, unlike in the first embodiment, is a spring member made of metal wire with the same structure as the first biasing member 138a and the second biasing member 138b. In the third biasing member 138c, the first end portion 138d is locked to the third cleat clamping portion 130c, and the second end portion 138e is in contact with a third screw member 142c for adjusting the spring force (the biasing force). The third screw member 142c is a hexagon socket set screw like the first screw member 142a, and the distal end position of the third screw member 142c on a side having the second surface 122b can be adjusted by using a turning tool, such as a hexagonal wrench, from a side having the first surface 122a. The spring force (the biasing force) of the third biasing member 138c becomes stronger as the distal end position of the third screw member 142c approaches the second surface 122b. 
Cleat
As shown in FIGS. 9 and 10, the cleat 150 comprises a first attaching portion 150a, a second attaching portion 150b, a connecting portion 150c and a pair of abutting surfaces 150d. The first attaching portion 150a, the second attaching portion 150b and the connecting portion 150c are attached to the first surface 122a of the pedal 110. The cleat 150 detachably engages a clamp part 124 that is attached to the pedal main body 122 of the pedal 110. The cleat 150 comprises a first engagement portion 152, a second engagement portion 154, and a third engagement portion 156, which detachably engages the clamp part 124.
The second attaching portion 150b is attached to the first surface 122a on the opposite side of the first attaching portion 150a with respect to the pedal shaft 120 of the pedal 110. The connecting portion 150c connects the first attaching portion 150a and the second attaching portion 150b to form a gap 160, in which a part of the pedal main body 122 is disposed between the first attaching portion 150a and the second attaching portion 150b. In the second embodiment, the connecting portion 150c is provided so that the first protrusion 132 and the second protrusion 134 as a part of the pedal main body 122 can be disposed in the gap 160.
In the second embodiment, the second engagement portion 154 and the third engagement portion 156 are provided in the first attaching portion 150a, and they detachably engage the clamp part 124. The first engagement portion 152 detachably engages the clamp part 124 in a position that is on the opposite side of the second engagement portion 154, with respect to the pedal shaft 120 of the bicycle pedal 110. Therefore, the first engagement portion 152 is provided in the second attaching portion 150b. The third engagement portion 156 detachably engages the clamp part 124 in a position that is offset from the second engagement portion 54 along the rotational center axis C1 direction of the pedal shaft 20. In the second embodiment, the third engagement portion 56 detachably engages the clamp part 124 in a position that is offset from the second engagement portion 154 along the rotational center axis C1 direction of the pedal shaft 120. Therefore, the third engagement portion 56 is provided in the first attaching portion 150a. Specifically, the first engagement portion 152 engages the first cleat clamping portion 130a of the clamp part 124. The second engagement portion 154 engages the second cleat clamping portion 130b of the clamp part 124. The third engagement portion 156 engages the third cleat clamping portion 130c of the clamp part 124. The first engagement portion 152, the second engagement portion 154, and the third engagement portion 156 are provided in the peripheral portion 150e of the cleat 150. The first engagement portion 152, the second engagement portion 154, and the third engagement portion 156 each comprises an attaching recess 158 that is formed to be recessed from the peripheral portion 150e of the cleat 150. The attaching recess 158 is formed to be recessed in a flat isosceles trapezoid shape in a plan view. The thickness of the first engagement portion 152, the second engagement portion 154, and the third engagement portion 156 on a side having the peripheral portion 150e of the cleat 150 is slightly smaller than the gap between the retaining portion 130e of the clamp part 124 and the first surface 122a. 
A pair of abutting surfaces 150d (refer to FIG. 10) are provided so that they abut a part of the pedal main body 122. The cleat 150 comprises a pair of long holes 162, which are used for attaching the cleat 150 to the shoe with a bolt member (not diagrammed). The pair of abutting surfaces 150d has a spherical, conical, or cylindrical shape. In the first embodiment, the pair of abutting surfaces 150d has a partially conical shape and abuts the side surfaces 132a of the first protrusion 132 as a part of the pedal main body 122. The abutting surfaces 150d each comprises a side surface shape that corresponds to one of the side surfaces 132a of the first protrusion 132. The distal end portion of the abutting surfaces 150d that are disposed opposing each other is formed in a flat V-shape. Meanwhile, in the case that the first protrusion has a conical shape or a spherical shape, the abutting surfaces can have partial cylindrical shapes.
Attaching and Detaching Operation of the Cleat
In a bicycle pedal system 106 configured in this way, when attaching a shoe to the pedal 110, the shoe is disposed on the first surface 122a of the pedal main body 122 of the pedal 110, in a state in which the cleat 150 is attached to the shoes by a bolt member that is not diagrammed. Then, the second engagement portion 154 and the third engagement portion 156 are engaged with the second cleat clamping portion 130b and the third cleat clamping portion 130c. In this state, if the rear portion of the shoes strongly steps onto the pedal 110, the retaining portion 130e will open due to the action of the guide surface 130f of the retaining portion 130e of the first cleat clamping portion 130a, and the first engagement portion 152 of the cleat 150 will be clamped by the first cleat clamping portion 130a. In a state in which the cleat 150 is retained by the clamp part 124, the pair of abutting surfaces 150d will be in contact with and will be disposed to the side surfaces 132a of the first protrusion 132. At this time, the cleat 150 will engage the pedal 110 at three positions. The gap between the first cleat clamping portion 130a and the third cleat clamping portion 130c, as well as the gap between the first cleat clamping portion 130a and the second cleat clamping portion 130b, can be made larger than the width of a conventional lever member that engages the pedal at one position in the rear. For this reason, the cleat 150 can be retained to the pedal 110 more stably than with the prior art. Additionally, the shoe to which the cleat 150 is attached becomes less likely to be tilted, and the pedaling force of the rider can be efficiently transmitted to the pedal 110. With this, the pedal can be operated more stably and efficiently. Meanwhile, as the attaching and detaching operation of the cleat 150, first engaging the first engagement portion 152 to the first cleat clamping portion 130a and then engaging the second engagement portion 154 and the third engagement portion 156 simultaneously into the second cleat clamping portion 130b and the third cleat clamping portion 130c by stepping onto the inner side of the pedal 110 is possible.
When detaching the shoe from the pedal 110, the heel side of the shoe is slightly twisted outside. Then, since the abutting surfaces 150d abut the side surfaces 132a of the first protrusion 132, the shoe rotates about the cleat rotational axis C2. At this time, the abutting surfaces 150d slide along the side surfaces 132a. When the shoe rotates, the corner of the opposing surface of the first attaching portion 150a and the second attaching portion 150b of the cleat 150 will ride on the inclined surface 136. With this, the cleat 150 separates from the first surface 122a of the pedal 110, and the third cleat clamping portion 130c will be pushed up from the first cleat clamping portion 130a and will be opened. As a result, the cleat 150 will detach from the pedal 110, and the shoe can be detached from the pedal 110. By making the side surface shapes of the abutting surfaces 150d and the side surfaces 132a partially spherical or partially conical, when the cleat 150 starts to separate from the first surface 122a, the cleat 150 can be moved in a direction that intersects with the cleat rotational axis C2 along the side surfaces 132a, and the cleat 150 can be easily detached from the pedal 110.
Third Embodiment
In FIGS. 11 and 12, the pedal 210 according to the third embodiment of the present invention is detachably engaged with the cleat 50, with the same configuration as in the first embodiment, that are attached to shoes. In the third embodiment, a bicycle pedal system 206 is configured by the pedal 210 and the cleat 50. In the pedal 210 of the third embodiment, the shape of the pedal main body 222 and the configuration of the clamp part 224 differ from those in the first embodiment. Therefore, in the following explanation, the pedal main body 222 and the clamp part 224 will be mainly explained; regarding the cleat 50 and the pedal shaft 20, which have the same configuration, the same reference symbols as those in the first embodiment will be used in FIGS. 11 and 12, and their explanations have been omitted.
As shown in FIG. 12, the pedal main body 222 is a plate-like member made of metal or synthetic resin that is formed so that two sides of a roughly isosceles triangular shape, when seen from the rear, are curved and recessed on a side having the rotational center axis C1. The pedal main body 222 comprises a first surface 222a that faces the shoe, a second surface 222b that is on the opposite side of the first surface 222a, and a stepped cylindrical shaft housing space 222c (refer to FIG. 11) in which the pedal shaft 20 is housed. Additionally, in order to achieve a reduction in the weight, the pedal main body 222 comprises a pair of slits 222h that extends through the first surface 222a and the second surface 222b and that is formed curving in an S-shape. The pair of slits 222h is disposed on both sides of the first protrusion 32.
As shown in FIG. 11, the pedal main body 222 comprises a first protrusion 32, a second protrusion 34, and at least one inclined surface 36 (two inclined surfaces in this embodiment) in the same way as in the first embodiment. Regarding the first protrusion 32, the second protrusion 34, and the inclined surface 36, the same reference symbols as those in the first embodiment have been used in FIG. 11, and their explanations have been omitted.
As shown in FIGS. 11 and 12, the clamp part 224 comprises three cleat clamping portions, a first cleat clamping portion 230a, a second cleat clamping portion 230b, and a third cleat clamping portion 230c. The third cleat clamping portion 230c is offset from the second cleat clamping portion 230b along the rotational center axis C1 direction. In the third embodiment, the third cleat clamping portion 230c is integrally formed with the pedal main body 222 and does not rotate with respect to the pedal main body 222. With this, the rigidity of the third cleat clamping portion 230c that is disposed on the outside of the bicycle can be increased, so that the third cleat clamping portion 230c is less likely to be damaged when falling. Additionally, the clamp part 224 comprises a first biasing member 238a and a second biasing member 238b (refer to FIG. 12). The first biasing member 238a biases the first cleat clamping portion 230a in a direction that retains the cleat 50. The second biasing member 238b biases the second cleat clamping portion 230b in a direction that retains the cleat 50.
As shown in FIG. 12, the first cleat clamping portion 230a, the second cleat clamping portion 230b, and the third cleat clamping portion 230c are disposed in the peripheral portion 222d of the pedal main body 222. Specifically, the first cleat clamping portion 230a and the second cleat clamping portion 230b are separately disposed in a first mounting recess 222e and a second mounting recess 222f that are disposed in three corners of the pedal main body 222. The first mounting recess 222e and the second mounting recess 222f are formed to be recessed inwards in a roughly rectangular shape extending through the first surface 222a and the second surface 222b. 
The first cleat clamping portion 230a and the second cleat clamping portion 230b are disposed sandwiching the pedal shaft 20 so that the pedal shaft 20 extends between them in the same way as in the first embodiment. Specifically, the first cleat clamping portion 230a and the second cleat clamping portion 230b are disposed so that they are in line symmetrically with respect to the rotational center axis C1. The third cleat clamping portion 230c is disposed between the first cleat clamping portion 230a and the second cleat clamping portion 230b when seen from the rotational center axis C1 direction. Also in the third embodiment, the third cleat clamping portion 230c is disposed in the intermediate position of the first cleat clamping portion 230a and the second cleat clamping portion 230b when seen from the rotational center axis C1 direction. That is, the third cleat clamping portion 230c is disposed on the rotational center axis C1. Additionally, the third cleat clamping portion 230c is disposed further on a side having the second end portion 20b than the first cleat clamping portion 230a or the second cleat clamping portion 230b. Therefore, the third cleat clamping portion 230c, the first cleat clamping portion 230a and the second cleat clamping portion 230b are disposed at an interval in the rotational center axis C1 direction (the lateral direction). Meanwhile, the first cleat clamping portion 230a and the second cleat clamping portion 230b can be disposed on a side having the second end portion 20b, and the third cleat clamping portion 230c can be disposed on a side having the first end portion 20a. 
As shown in FIG. 12, the first cleat clamping portion 230a is rotatably provided around a first axis S1 by a first shaft member 40a that is disposed to the pedal main body 222 in the first mounting recess 222e along the first axis S1 direction. The first axis S1 extends in a direction that is parallel to the first surface 222a, as well as in a direction that intersects with a first straight line L1, which extends in the radial direction from the cleat rotational axis C2 toward the first cleat clamping portion 230a. Preferably, the first axis S1 extends in a direction that is essentially perpendicular to the first straight line L1.
The second cleat clamping portion 230b is rotatably provided around a second axis S2 by a second shaft member 40b that is disposed to the pedal main body 222 in the second mounting recess 222f along the second axis S2 direction. The second axis S2 extends in a direction that is parallel to the first surface 222a, as well as in a direction that intersects with a second straight line L2, which extends in the radial direction from the cleat rotational axis C2 toward the second cleat clamping portion 230b. Preferably, the second axis S2 extends in a direction that is essentially perpendicular to the second straight line L2. The second straight line L2 is disposed in a line symmetrically with the first straight line L1 with respect to the rotational center axis C1.
As shown in FIGS. 11 and 12, the first cleat clamping portion 230a and the second cleat clamping portion 230b each comprise a main body portion 230d and a retaining portion 230e that retains the cleat 50. The main body portion 230d is rotatably supported by the pedal main body 222. The retaining portion 230e protrudes from the main body portion 230d toward the first protrusion 32 and is disposed with an interval that is able to retain the cleat 50 between the first surface 222a. Each of the retaining portions 230e of the first cleat clamping portion 230a and the second cleat clamping portion 230b is biased in a direction toward the center (the first protrusion 32) of the pedal main body 222 by the first biasing member 238a and the second biasing member 238b, respectively. A guide surface 230f that inclines toward the first surface 222a is formed in the retaining portion 230e. The guide surface 230f is provided to pivot the retaining portion 230e in the opening direction (counterclockwise in FIG. 12) against the biasing force of the first biasing member 238a and the second biasing member 238b when the first cleat clamping portion 230a and the second cleat clamping portion 230b are pressed with the cleat 50.
As shown in FIG. 12, the first biasing member 238a is, for example, a torsion coil spring made of metal spring wire with a rectangular cross section. In the third embodiment, the first biasing member 238a and the second biasing member 238b are configured in the same way as the third biasing member 38c in the first embodiment. The first end portion 238d of the first biasing member 238a is locked to the first cleat clamping portion 230a, and the second end portion 238e is locked by an adjustment member 242a for adjusting the spring force. In the same way, the first end portion 238f of the second biasing member 238b is locked to the second cleat clamping portion 230b, and the second end portion 238g is locked by an adjustment member 242b for adjusting the spring force.
The adjustment member 242a and the adjustment member 242b are, for example, cylindrical members. The adjustment member 242a is rotatably mounted to the second surface 222b about an axis that is parallel to the first axis S1. The adjustment member 242b is rotatably mounted to the second surface 222b about an axis that is parallel to the second axis S2. Formed on the outer peripheral surface of the adjustment member 242a and the adjustment member 242b are planar portions that cut away a part of the cylindrical surface at, for example, three locations in the circumferential direction. Each of the planar portions is formed so that the distance to the center of the adjustment member 242a (or the adjustment member 242b) is different from each other. The second end portion 238e of the first biasing member 238a (or the second end portion 242g of the adjustment member 242b) is selectively locked to the above-described plurality of planar portions. The adjustment member 242a and the adjustment member 242b comprise a tool locking hole 242d to which tools such as a hexagonal wrench can be mounted. The planar portion that locks the second end portion 238e of the first biasing member 238a (or the second end portion 238g of the second biasing member 238b) is changed by turning the adjustment member 242a (or the adjustment member 242b) by mounting a tool to this tool locking hole 242d and changing the spring force (the biasing force).
As mentioned above, the third cleat clamping portion 230c is integrally formed with the pedal main body 222. The third cleat clamping portion 230c comprises a main body portion 230g that is integrally formed with the pedal main body 222, as well as a retaining portion 230h that is integrally formed with the main body portion 230g and that retains the cleat 50. The retaining portion 230h protrudes from the main body portion 230g toward the first protrusion 32 and is disposed with an interval that is able to retain the cleat 50 between the first surface 222a. 
Attaching and Detaching Operation of the Cleat
In a bicycle pedal system 206 configured in this way, when attaching a shoe to the pedal 210, the shoe is disposed on the first surface 222a of the pedal main body 222 of the pedal 210 in a state in which the cleat 50 is attached to the shoe by a bolt member that is not diagrammed. Then, the third engagement portion 56 is engaged with the third cleat clamping portion 230c on the outside of the shoe (a side having the second end portion 20b of the pedal shaft 20). In this state, if the inside of the shoe (a side having the first end portion 20a of the pedal shaft 20) strongly steps onto the pedal 210, the retaining portions 230e will open due to the action of the guide surface 230f of each of the retaining portions 230e of the first cleat clamping portion 230a and the second cleat clamping portion 230b; then, the first engagement portion 52 and the second engagement portion 54 of the cleat 50 will be separately clamped by the first cleat clamping portion 230a and the second cleat clamping portion 230b. In a state in which the cleat 50 is retained by the clamp part 224, the pair of abutting surfaces 50d will be in contact with and will be disposed to the side surfaces 32a of the first protrusion 32. At this time, the cleat 50 will engage the pedal 210 at three positions, and the gap between the first cleat clamping portion 230a and the third cleat clamping portion 230c, as well as the gap between the second cleat clamping portion 230b and the third cleat clamping portion 230c, can be made to be larger than the width of a conventional lever member that engages the pedal at one position in the rear. For this reason, the cleat 50 can also be retained to the pedal 210 more stably in the third embodiment than with the prior art. Additionally, the shoes to which the cleat 50 is attached become less likely to be tilted, and the pedaling force of the rider can be efficiently transmitted to the pedal 210. With this, the pedal 210 can be operated more stably and efficiently.
When detaching the shoe from the pedal 210, the heel side of the shoe is slightly twisted outside. Then, since the abutting surfaces 50d abuts the side surfaces 32a of the first protrusion 32, the shoe rotates about the cleat rotational axis C2. At this time, the abutting surfaces 50d slides along the side surfaces 32a. When the shoe rotates, the corner of the opposing surface of the first attaching portion 50a and the second attaching portion 50b of the cleat 50 will ride on the inclined surface 36. With this, the cleat 50 is separated from the first surface 222a of the pedal 210, and the first cleat clamping portion 230a and the second cleat clamping portion 230b will be pushed up and will be opened. As a result, the cleat 50 will be detached from the pedal 210, and the shoe can be detached from the pedal 210. By making the side surface shape of the abutting surfaces 50d and the side surfaces 32a spherical or conical, when the cleat 50 start to separate from the first surface 222a, the cleat 50 can be moved in a direction that intersects with the cleat rotational axis C2 along the side surfaces 32a, and the cleat 50 can be easily detached from the pedal 210.
Modified Example of the Third Embodiment
In FIG. 13, a pedal 310 according to a modified example of the third embodiment of the present invention (hereinafter simply referred to as the modified example) is detachably engaged with the cleat 50 that has the same configuration as those in the first embodiment that is attached to a shoe. In the modified example, a bicycle pedal system 306 is configured by a pedal 310 and cleat 50. In the pedal 310 of the modified example, the shape of the pedal main body 322 and the configuration of the third cleat clamping portion 330c differ from those in the first embodiment. Therefore, in the following explanation, the pedal main body 322 and the clamp part 324 will be mainly explained; regarding the cleat 50 and the pedal shaft 20, which have the same configuration, the same reference symbols as those used in the first embodiment and the third embodiment will be used in FIGS. 13 to 17, and their explanations have been omitted.
As shown in FIGS. 13 and 14, the pedal main body 322 is a plate-like member made of metal or synthetic resin, and this pedal main body has a roughly isosceles triangular shape in a plan view. As shown in FIGS. 13 to 16, the pedal main body 322 comprises a first surface 322a that faces the shoe, a second surface 322b that is on the opposite side of the first surface 322a, and a stepped cylindrical shaft housing space 322c (refer to FIG. 17) in which the pedal shaft 20 is housed. Additionally, in order to achieve a reduction in the weight, the pedal main body 322 comprises two slits 322h that extend through the first surface 322a and the second surface 322b. The slits 322h are disposed on both sides of the first protrusion 32.
As shown in FIG. 13, the pedal main body 322 comprises a first protrusion 32, a second protrusion 34, and at least one inclined surface 36 (two inclined surfaces in this embodiment) in the same way as the first embodiment. Regarding the first protrusion 32, the second protrusion 34, and the inclined surfaces 36, the same reference symbols as those used in the first embodiment have been used in FIG. 13, and their explanations have been omitted.
As shown in FIGS. 13 and 14, the clamp part 324 comprises three cleat clamping portions, a first cleat clamping portion 330a, a second cleat clamping portion 330b and a third cleat clamping portion 330c. The third cleat clamping portion 330c is offset from the second cleat clamping portion 330b along the rotational center axis C1 direction. In the modified example, the third cleat clamping portion 330c is integrally formed with the pedal main body 322 and does not rotate with respect to the pedal main body 322. With this, the rigidity of the third cleat clamping portion 330c that is disposed on the outside of the bicycle can be increased, so that the third cleat clamping portion 330c is less likely to be damaged when falling.
The clamp part 324 also comprises a first biasing member 338a with the same configuration as that of the third embodiment, as well as a second biasing member 338b (refer to FIG. 14). The first biasing member 338a biases the first cleat clamping portion 330a in a direction that retains the cleat 50. The second biasing member 338b biases the second cleat clamping portion 330b in a direction that retains the cleat 50.
As shown in FIG. 14, the first cleat clamping portion 330a, the second cleat clamping portion 330b, and the third cleat clamping portion 330c are disposed in the peripheral portion 322d of the pedal main body 322. Specifically, the first cleat clamping portion 330a and the second cleat clamping portion 330b are separately disposed in a first mounting recess 322e and a second mounting recess 322f that are disposed in three corners of the pedal main body 322. The first mounting recess 322e and the second mounting recess 322f are formed to be recessed inwards in a roughly rectangular shape that extends through the first surface 322a and the second surface 322b. 
The first cleat clamping portion 330a and the second cleat clamping portion 330b are disposed sandwiching the pedal shaft 20 so that the pedal shaft 20 extends between them in the same way as in the third embodiment. Also in the modified example, the third cleat clamping portion 330c is disposed in the intermediate position of the first cleat clamping portion 330a and the second cleat clamping portion 330b when seen from the rotational center axis C1 direction. That is, the third cleat clamping portion 330c is disposed on the rotational center axis C1 when seen in a plan view, as shown in FIG. 14. Additionally, the third cleat clamping portion 330c is disposed further on a side having the second end portion 20b than the first cleat clamping portion 330a or the second cleat clamping portion 330b. Therefore, the third cleat clamping portion 330c, the first cleat clamping portion 330a and the second cleat clamping portion 330b are disposed at an interval in the rotational center axis C1 direction (the lateral direction). Meanwhile, the first cleat clamping portion 330a and the second cleat clamping portion 330b can be disposed on a side having the second end portion 20b, and the third cleat clamping portion 330c can be disposed on a side having the first end portion 20a. 
As shown in FIG. 14, the first cleat clamping portion 330a is rotatably provided around a first axis S1 by a first shaft member 40a that is disposed to the pedal main body 322 in the first mounting recess 322e along the first axis S1 direction. The first axis S1 extends in a direction that is parallel to the first surface 322a, as well as in a direction that intersects with a first straight line L1, which extends in the radial direction from the cleat rotational axis C2 toward the first cleat clamping portion 330a. Preferably, the first axis S1 extends in a direction that is essentially perpendicular to the first straight line L1.
The second cleat clamping portion 330b is rotatably provided around a second axis S2 by a second shaft member 40b that is disposed to the pedal main body 322 in the second mounting recess 322f along the second axis S2 direction. The second axis S2 extends in a direction that is parallel to the first surface 322a, as well as in a direction that intersects with a second straight line L2, which extends in the radial direction from the cleat rotational axis C2 toward the second cleat clamping portion 330b. Preferably, the second axis S2 extends in a direction that is essentially perpendicular to the second straight line L2. The second straight line L2 is disposed in a line symmetrically with the first straight line L1 with respect to the rotational center axis C1.
As shown in FIGS. 13, 14 and 15, the first cleat clamping portion 330a and the second cleat clamping portion 330b each comprise a main body portion 330d and a retaining portion 330e that retains the cleat 50. The main body portion 330d is rotatably supported by the pedal main body 322. The retaining portion 330e protrudes from the main body portion 330d toward the first protrusion 32 and is disposed with an interval that is able to retain the cleat 50 between the first surface 322a. As shown in FIG. 15, the retaining portions 330e of the first cleat clamping portion 330a and the second cleat clamping portion 330b each comprise an engagement surface 330g that is in contact with the cleat 50. The engagement surface 330g can be positioned between the first surface 322a and the endmost portion 322g of the first protrusion 32 in the direction that is perpendicular to the first surface 322a. 
Each of the retaining portions 330e of the first cleat clamping portion 330a and the second cleat clamping portion 330b is biased in a direction toward the center (the first protrusion 32) of the pedal main body 322 by the first biasing member 338a and the second biasing member 338b, respectively. A guide surface 330f that inclines toward the first surface 322a is formed in the retaining portion 330e. The guide surface 330f is provided to pivot the retaining portion 330e in the opening direction (counterclockwise in FIG. 12) against the biasing force of the first biasing member 338a and the second biasing member 338b when the first cleat clamping portion 330a and the second cleat clamping portion 330b have been pressed with the cleat 50.
The first biasing member 338a and the second biasing member 338b are torsion coil springs made of a metal spring wire with a rectangular cross section. The first end portion of the first biasing member 338a is locked to the first cleat clamping portion 330a, and the second end portion is locked by an adjustment member that is not diagrammed for adjusting the spring force. In the same way, the first end portion of the second biasing member 338b is locked to the second cleat clamping portion 330b, and the second end portion is locked by an adjustment member that is not diagrammed for adjusting the spring force. The adjustment member is configured in the same way as in the third embodiment and is, for example, a cylindrical member. The spring force (the biasing force) of the first biasing member 338a and the second biasing member 338b are each changed by turning the adjustment member.
As shown in FIGS. 15 to 17, the third cleat clamping portion 330c is inclined with respect to the first surface 322a and extends in the rotational center axis C1 direction. The third cleat clamping portion 330c is integrally formed with the pedal main body 322. Therefore, the third cleat clamping portion 330c is non-rotatably coupled to the pedal main body 322. The third cleat clamping portion 330c comprises a pair of connecting portions 330j that are integrally formed with the pedal main body 322, retaining portions 330e that are integrally formed with the pair of connecting portions 330j and that are engageable with the cleat 50, and a recess 330i (refer to FIG. 16) that is formed in a portion that faces the retaining portions 330e. The connecting portions 330j connect the two ends of the retaining portion 330e and the pedal main body 322; more specifically, a pair of connecting portions 330j connects the two ends of the retaining portion 330e in the direction that is perpendicular to the rotational center axis C1 and the pedal main body 322. The connecting portions 330j are inclined with respect to the first surface 322a and extend along the rotational center axis C1 direction. Meanwhile, the connecting portions 330j are not limited to a shape that is inclined with respect to the first surface 332a, and they can be a shape that is parallel to the first surface 332a or a shape that is perpendicular to the first surface 332a. 
The retaining portion 330e has a thickness that is less than the thickness of the pedal main body 322 in the topmost portion. Here, the thickness of the pedal main body 322 in the topmost portion is a thickness that passes through the first protrusion 32 in a direction that is perpendicular to the first surface 322a; specifically, this is the thickness of the endmost portion 322g of the first protrusion 32. The retaining portion 330e is disposed in a position that is away from the first surface 322a in a direction that intersects with the first surface 322a. The retaining portion 330e comprises an engagement surface 330g that contacts the cleat 50. The recess 330i is formed in a portion that faces the engagement surface 330g. As shown in FIG. 16, the recess 330i is surrounded by a first virtual line VL1, a second virtual line VL2, and the outline of the connecting portion 330j, and this recess is configured by a triangular space as viewed from the side surface side. The first virtual line VL1 extends from the distal end of the second surface 322b of the pedal main body 322 along the rotational center axis C1 direction. The second virtual line VL2 extends from the distal end of the retaining portion 330e toward the first virtual line VL1 along the cleat rotational axis C2 direction.
The engagement surface 330g is disposed in a position that is away from the first surface 322a in a direction that intersects with the first surface 322a. More specifically, the engagement surface 330g of the third cleat clamping portion 330c is positioned between the first surface 322a and the endmost portion 322g of the first protrusion 32 in the direction that is perpendicular to the first surface 322a, in the same way as the first cleat clamping portion 330a and the second cleat clamping portion 330b. With this, the position of the retaining surface of the attaching recess 58 of the first engagement portion 52, the second engagement portion 54, and the third engagement portion 56 of the cleat 50 will be in a position that is lower than the first protrusion 32 with respect to the first surface 322a. For this reason, the pedal can be configured to be thinner. The third cleat clamping portion 330c is formed between the retaining portion 330e and the pedal main body 322 and comprises an opening 330h into which the cleat 50 is inserted.
Attaching and Detaching Operation of the Cleat
In a bicycle pedal system 306 configured in this way, when attaching a shoe to the pedal 310, the shoe is disposed on the first surface 322a of the pedal main body 322 of the pedal 310 in a state in which the cleat 50 is attached to the shoes by a bolt member that is not diagrammed. Then, the third engagement portion 56 is engaged with the third cleat clamping portion 330c on the outside of the shoe (a side having the second end portion 20b of the pedal shaft 20). At this time, the retaining portion 330e of the third cleat clamping portion 330c that engages the third engagement portion 56 comprises an opening 330h that is formed in an arch shape and into which the cleat 50 is inserted, so that the third engagement portion 56 of the cleat 50 easily engages the engagement surface 330g. 
In this state, if the inside of the shoe (a side having the first end portion 20a of the pedal shaft 20) strongly steps onto the pedal 310, the retaining portions 330e will open due to the action of the guide surface 330f of each of the retaining portions 330e of the first cleat clamping portion 330a and the second cleat clamping portion 330b; then, the first engagement portion 52 and the second engagement portion 54 of the cleat 50 will be separately clamped by the first cleat clamping portion 330a and the second cleat clamping portion 330b. In a state in which the cleat 50 is retained by the clamp part 324, the pair of abutting surfaces 50d will be in contact with and will be disposed to the side surfaces 32a of the first protrusion 32. At this time, the cleat 50 will engage the pedal 310 at three positions, and the gap between the first cleat clamping portion 330a and the third cleat clamping portion 330c, as well as the gap between the second cleat clamping portion 330b and the third cleat clamping portion 330c, can be made larger than the width of a conventional lever member that engages the pedal at one position in the rear. For this reason, in the modified example as well, the cleat 50 can be retained to the pedal 310 more stably than with the prior art. Additionally, the shoe to which the cleat 50 is attached becomes less likely to be tilted, and the pedaling force of the rider can be efficiently transmitted to the pedal 310. With this, the pedal 310 can be operated more stably and efficiently.
Additionally, the third cleat clamping portion 330c is inclined with respect to the first surface 322a and extends along the rotational center axis direction. A recess 330i is also formed in a portion that faces the engagement surface 330g. For this reason, a clearance for preventing the axial end portion of the second surface 322b of the pedal main body 322 of the pedal 310 from coming into contact with the ground while turning corners, etc., can be formed.
When detaching the shoe from the pedal 310, the heel side of the shoe is slightly twisted outside in the same way as in the third embodiment. Then, since the abutting surfaces 50d abuts the side surfaces 32a of the first protrusion 32, the shoe rotates about the cleat rotational axis C2. At this time, the abutting surfaces 50d slide along the side surfaces 32a. When the shoe rotates, the corner of the opposing surface of the first attaching portion 50a and the second attaching portion 50b of the cleat 50 will ride on the inclined surface 36. With this, the cleat 50 will separate from the first surface 322a of the pedal 210, and the first cleat clamping portion 330a and the second cleat clamping portion 330b will be pushed up and will be opened. As a result, the cleat 50 will be detached from the pedal 310, and the shoe can be detached from the pedal 310. By making the side surface shape of the abutting surfaces 50d and the side surfaces 32a spherical or conical, when the cleat 50 starts to separate from the first surface 322a, the cleat 50 will be moved in a direction that intersects with the cleat rotational axis C2 along the side surfaces 32a, and the cleat 50 can be easily detached from the pedal 310.
Other Embodiments
(a) In the above-described embodiments, three or more cleat clamping portions were provided only to the first surface 22a (122a, 222a, or 322a), but the present invention is not limited to this configuration. Three or more cleat clamping portions can be provided to the second surface 22b (122b, 222b, or 322b) that is on the opposite side of the first surface 22a (122a, 222a, or 322a).
(b) In the above-described embodiments, at least two cleat clamping portions were rotatably provided to the pedal main body 22 (122, 222, or 322), but the present invention is not limited to this configuration. The only requirement is that at least one of the three cleat clamping portions is rotatable.
(c) In the above-described embodiment, the number of cleat clamping portions was three, but the present invention is not limited to this configuration. The number of cleat clamping portions can be any number that is three or more. However, in order to make the intervals in the cleat clamping portions large, the number of cleat clamping portions is preferably in a range of three to five.
(d) In the above-described embodiment, the side surfaces 32a (or 132a) of the first protrusion 32 (or 132) was conical shape, but this surface may have a spherical or cylindrical surface shape. Additionally, the abutting surfaces 50d (or 160) of the cleat 50 (or 150) had a conical shape, but this surface may have a spherical or cylindrical surface shape.
(e) In the above-described embodiment, a torsion coil spring was used as the biasing member, but the present invention is not limited to this configuration. However, the cleat clamping portion can be made to be elastics. Additionally, a spring member besides a torsion coil spring (for example, a leaf spring such as a torsion spring, a spring washer, or a coil spring) can also be used.
(f) In the third embodiment and the modified example, the third cleat clamping portions 230c and 330c were integrally formed with the pedal main bodies 222 and 322, but they may be formed separately. In this case, the third cleat clamping portions 230c and 330c can be non-rotatably coupled to the pedal main bodies 222 and 322; they also may be rotatably provided to the pedal main bodies 222 and 322.
(g) Besides the modified example of the third embodiment, the engagement surface 330g to which the cleat 50 (or 150) is in contact is not mentioned, but the present invention is not limited to this configuration. The retaining portion 30e (130e, or 230e) of the first cleat clamping portion 30a (130a or 230a), the second cleat clamping portion 30b (130b or 230b), and the third cleat clamping portion 30c (130c or 230c) of the first embodiment, the second embodiment, and the third embodiment of the present invention comprise the same engagement surface as the modified example. That is, the retaining portion 30e (130e or 230e) comprises an engagement surface that is positioned between the first surface 322a and the endmost portion of the first protrusion 32 in the direction that is perpendicular to the first surface 22a (122a or 222a).
(h) In the third embodiment, the recess 330i is configured by a space that is recessed in a triangular shape from the side view, but the recess of the present invention is not limited to this configuration. The recess may be a space that is configured by being recessed in a stepped shape from the side view, or this recess may be configured by a space that is recessed by being curved concavely or convexly.
While only selected embodiments have been chosen to illustrate the present invention, it will be apparent to those skilled in the art from this disclosure that various changes and modifications can be made herein without departing from the scope of the invention as defined in the appended claims. For example, unless specifically stated otherwise, the size, shape, location or orientation of the various components can be changed as needed and/or desired so long as the changes do not substantially affect their intended function. Unless specifically stated otherwise, components that are shown directly connected or contacting each other can have intermediate structures disposed between them so long as the changes do not substantially affect their intended function. The functions of one element can be performed by two, and vice versa unless specifically stated otherwise. The structures and functions of one embodiment can be adopted in another embodiment. It is not necessary for all advantages to be present in a particular embodiment at the same time. Every feature which is unique from the prior art, alone or in combination with other features, also should be considered a separate description of further inventions by the applicant, including the structural and/or functional concepts embodied by such feature(s). Thus, the foregoing descriptions of the embodiments according to the present invention are provided for illustration only, and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.

## Claims

1. A bicycle pedal that is detachable and engageable with a cleat that can be attached to a shoe, the bicycle pedal comprising:
a pedal shaft having a rotational center axis;
a pedal main body haying a first surface and a second surface, the second surface being on an opposite side of the first surface, and the pedal main body being rotatably supported by the pedal shaft around the rotational center axis, and
a clamp part comprising a first cleat clamping portion, a second cleat clamping portion and a third cleat clamping portion that detachably retain the cleat on at least the first surface of the pedal main body,
the third cleat clamping portion being spaced away from the second cleat clamping portion in a direction along the rotational center axis,
the pedal shaft extending between the first cleat clamping portion and the second cleat clamping portion,
the second and third cleat clamping portions being disposed on a same side with respect to the pedal shaft,
the third cleat clamping portion being disposed between the first cleat clamping portion and the second cleat clamping portion as seen from the direction along the rotational center axis, and
the third cleat clamping portion is disposed in a position that straddles the rotational center axis as seen from a direction that is perpendicular to the first surface.

2. The bicycle pedal as recited in claim 1, wherein
the pedal shaft comprises a first end portion that is attached to a bicycle crank, and a second end portion that is on an opposite side of the first end portion with respect to the rotational center axis, and
the third cleat clamping portion is disposed adjacent the second end portion of the pedal shaft, and the first and the second cleat clamping portions are disposed adjacent the first end portion of the pedal shaft.

3. The bicycle pedal as recited in claim 1, wherein
the third cleat clamping portion comprises a retaining portion that is engageable with the cleat, and a recess that faces the retaining portion.

4. The bicycle pedal as recited in claim 3, wherein
the retaining portion is disposed in a position that is offset from the first surface in a direction that intersects with the first surface.

5. The bicycle pedal as recited in claim 4, wherein
the retaining portion has a thickness that is less than a thickness of the pedal main body in a topmost portion.

6. The bicycle pedal as recited in claim 4, wherein
the retaining portion comprises an engagement surface that is configured to contact the cleat, and
the recess is formed in a portion that faces the engagement surface.

7. The bicycle pedal as recited in claim 6, wherein
the engagement surface is disposed in a position that is offset from the first surface in a direction that intersects with the first surface.

8. The bicycle pedal as recited in claim 3, wherein
the third cleat clamping portion comprises a connecting portion that connects the retaining portion and the pedal main body, and
the connecting portion is inclined with respect to the first surface and extends along the rotational center axis direction.

9. The bicycle pedal as recited in claim 8, wherein
the connecting portion connects two ends of the retaining portion and the pedal main body.

10. The bicycle pedal as recited in claim 3, wherein
the third cleat clamping portion is integrally formed with the pedal main body.

11. The bicycle pedal as recited in claim 3, wherein
the retaining portion and the pedal main body are arranged to define an opening between the retaining portion and the pedal main body and into which the cleat is inserted.

12. The bicycle pedal as recited in claim 3, wherein
the third cleat clamping portion is non-rotatably coupled to the pedal main body.

13. The bicycle pedal as recited in claim 1, wherein
at least one of the first cleat clamping portion, the second cleat clamping portion, and the third cleat clamping portion is rotatably coupled to the pedal main body.

14. The bicycle pedal as recited in claim 13, wherein
the first cleat clamping portion, the second cleat clamping portion, and the third cleat clamping portion are rotatably coupled to the pedal main body.

15. The bicycle pedal as recited in claim 13, wherein
the clamp part comprises three biasing members that bias the first cleat clamping portion, the second cleat clamping portion, and the third cleat clamping portion in a direction that retains the cleat.

16. The bicycle pedal as recited in claim 1, wherein the pedal main body comprises a first protrusion that protrudes from the first surface.

17. The bicycle pedal as recited in claim 16, wherein
the first protrusion comprises a partially spherical or conical side surface.

18. The bicycle pedal as recited in claim 16, wherein
the pedal main body comprises a second protrusion that protrudes from the first surface and that extends along the rotational center axis.

19. The bicycle pedal as recited in claim 18, wherein
the first protrusion is provided in an intermediate portion of the second protrusion with respect to the rotational center axis and protrudes with respect to a side surface of the second protrusion.

20. The bicycle pedal as recited in claim 18, wherein
the pedal main body comprises an inclined surface that inclines in a direction away from the pedal shaft from the second protrusion to the first surface.

21. The bicycle pedal as recited in claim 20, wherein
the pedal shaft comprises a first end portion that is attached to a bicycle crank, and a second end portion that is on the opposite side of the first end portion with respect to the rotational center axis, and
the inclined surface is provided on a side of the first protrusion having the first end portion with respect to the first protrusion.

22. The bicycle pedal as recited in claim 16, wherein
the first cleat clamping portion, the second cleat clamping portion, and the third cleat clamping portion each comprise an engagement surface that is configured to contact the cleat, and
the engagement surface is positioned between the first surface and an endmost portion of the first protrusion in a direction that is perpendicular to the first surface.

23. The bicycle pedal as recited in claim 1, wherein
the first cleat clamping portion, the second cleat clamping portion, and the third cleat clamping portion are disposed on a peripheral portion of the pedal main body.

24. A bicycle pedal system comprising:
the bicycle pedal as recited in claim 1, and
a cleat that detachably engages the clamp part of the pedal main body of the bicycle pedal, the cleat comprising:
a first engagement portion configured to detachably engage the clamp part,
a second engagement portion configured to detachably engage the clamp part in a position that is on an opposite side of the first engagement portion, with respect to the pedal shaft of the bicycle pedal, and
a third engagement portion configured to detachably engage the clamp part in a position away from the second engagement portion in the direction of the rotational center axis of the pedal shaft.

25. The cleat as recited in claim 24, wherein
the third engagement portion is configured to engage the clamp part on a side having the second engagement portion with respect to the pedal shaft.

26. The cleat as recited in claim 24, wherein
the third engagement portion is configured to engage the clamp part in a position between the first engagement portion and the second engagement portion as seen along the rotational center axis.

27. The cleat as recited in claim 24, further comprising
an abutting surface that abuts a part of the pedal main body, the abutting surface partially forming a spherical shape or a conical shape.

28. The cleat as recited in claim 24, wherein
the first engagement portion, the second engagement portion, and the third engagement portion are provided on a peripheral portion of the cleat.

29. A bicycle pedal that is detachable and engageable with a cleat that can be attached to a shoe, the bicycle pedal comprising:
a pedal shaft having a rotational center axis;
a pedal main body having a first surface and a second surface, the second surface being on an opposite side of the first surface, and the pedal main body being rotatably supported by the pedal shaft around the rotational center axis, and
a clamp part comprising a first cleat clamping portion, a second cleat clamping portion and a third cleat clamping portion that detachably retain the cleat on at least the first surface of the pedal main body,
the third cleat clamping portion being spaced away from the second cleat clamping portion in a direction along the rotational center axis,
the pedal shaft extending between the first cleat clamping portion and the second cleat clamping portion,
at least one of the first cleat clamping portion, the second cleat clamping portion, and the third cleat clamping portion being rotatably coupled to the pedal main body, and
the clamp part comprising three biasing members that bias the first cleat clamping portion, the second cleat clamping portion, and the third cleat clamping portion in a direction that retains the cleat.

30. A bicycle pedal that is detachable and engageable with a cleat that can be attached to a shoe, the bicycle pedal comprising:
a pedal shaft having a rotational center axis;
a pedal main body having a first surface and a second surface, the second surface being on an opposite side of the first surface, and the pedal main body being rotatably supported by the pedal shaft around the rotational center axis, and
a clamp part comprising a first cleat clamping portion, a second cleat clamping portion and a third cleat clamping portion that detachably retain the cleat on at least the first surface of the pedal main body,
the pedal main body comprising a first protrusion that protrudes from the first surface, and
the first protrusion comprising a partially spherical or conical side surface.

31. A bicycle pedal that is detachable and engageable with a cleat that can be attached to a shoe, the bicycle pedal comprising:
a pedal shaft having a rotational center axis;
a pedal main body having a first surface and a second surface, the second surface being on an opposite side of the first surface, and the pedal main body being rotatably supported by the pedal shaft around the rotational center axis, and
a clamp part comprising a first cleat clamping portion, a second cleat clamping portion and a third cleat clamping portion that detachably retain the cleat on at least the first surface of the pedal main body,
the pedal main body comprising a first protrusion that protrudes from the first surface and a second protrusion that protrudes from the first surface and extends along the rotational center axis, and
the first protrusion being provided in an intermediate portion of the second protrusion with respect to the rotational center axis and protruding with respect to a side surface of the second protrusion.