Patent Application
20120090374
The present invention relates to a method for fabricating wings of bicycle pedals and particularly to a method to fabricate wings of bicycle pedals in an integrated fashion.
In recent years bicycle becomes very popular and is widely used as transportation means, means for exercise and physical fitness, or leisure and sightseeing activities, either in cities or country sites. It also has been designated as one of sport contest or extreme sport items long time ago. With increasingly popularity of bicycle sports, bicycle users, whether general users, professionals or athletes, have higher demands on nearly every bicycle feature, such as maneuverability, user-friendliness of operation interface or riding comfort. To meet these requirements many types of accessories have been developed for mountain bikes or road bikes. One of them aims to improve treading efficiency of users by providing a coupling system to hold bicycle shoe and pedal together.
For instance, U.S. Pat. No. 7,225,703 discloses a bicycle pedal and crank apparatus. It mainly includes a clipless bicycle pedal and a crank arm. The clipless pedal includes a shaft, a wing, a body and a spring. The wing, body and spring are coupled on the shaft. The wing and spring are held in the body. The spring is located in the wing. The shaft has one end coupled with a sleeve fastened through a screw, and other end coupled with the crank arm through a screw ring. The screw ring holds a bearing inside. A user can latch a shoe cleat at the bottom of the bicycle shoe in the wing (or body). When the user rides the bicycle the cleat is tightly coupled with the wing, and is not easy to separate therefrom. When releasing of the cleat is desired, the cleat has to be positioned at a specific angle with the wing. Such a design allows the bicycle shoe to form a secure coupling with the pedal, hence user's stepping force can be transmitted to the crank more efficiently. Treading also is more stable.
To fabricate the aforesaid wing (or body), U.S. Pat. No. 6,851,189 discloses a method of fabrication a clipless bicycle pedal. A metal plate is stamped to form a flat inner wing and outer wing element. The wing element includes a pair of annular portions each has a spindle hole, and two ends formed respectively a tab and a groove formed in shapes complemented with each other. The wing then is bent in a rectangular structure with a plurality of bend portions. Finally the tab and groove are soldered or brazed together to become a joint.
The aforesaid conventional joining process to fabricate the wing forms a joining interface which has strength far smaller than the wing body. During the joining process a slight negligence of control parameters could result in defective joining interface. Hence when the wing receives continuous treading force of the user for a long duration, or the treading force is inadvertently greater, stress concentration is easily formed on the joining interface and results in fracture. This is especially likely to take place during contests or exercises that require high speed riding. The unstable structural strength on such a pedal system creates safety concern for the user during riding. Moreover, the aforesaid fabrication method is difficult to control structural uniformity during joining of the joining interface between the tab and groove. Production yield could drop and production cost is higher.
The primary object of the present invention is to solve the problem that the conventional method for fabricating wings of bicycle pedals employing soldering or brazing process results in deficiency of structural strength.
To achieve the foregoing object the present invention provides a method for fabricating wings of bicycle pedals that includes the following steps:
stamping a plate to form a preformed body which includes an opening and a body surrounding the opening that contains a preset working surface formed thereon. The working surface has a preset force receiving zone adjacent to the opening. The body further includes a first expanded portion, a second expanded portion and two arched portions bridging two sides of the first and second expanded portions respectively; and applying a punching force to the force receiving zone to bend the first expanded portion, second expanded portion and arched portions such that the working surface on the first and second expanded portions to be opposite each other and the working surface on the arched portions to be formed in a curved surface opposing each other.
In an embodiment of the present invention, before applying the punching force the preformed body is positioned between an upper mold and a lower mold that clamp an edge portion of the body. When applying the punching force the upper mold escapes the edge portion of the body so that the first expanded portion, second expanded portion and arched portions can be bent between the upper and lower molds.
The fabrication method of the present invention set forth above provides many benefits over the conventional techniques, notably:
1. The wings are manufactured in an integrated manner without forming the joining interface, hence the strength of the wings increases significantly and safety of users during riding is enhanced and the lifespan of the wings is longer.
2. The present invention employs mechanical process to replace soldering or brazing process in the conventional techniques, and can directly form a desired profile through deformation under forces rather than joining through chemical reactions in the conventional techniques, thus can greatly reduce duration of manufacturing the wings and improve production efficiency.
The foregoing, as well as additional objects, features and advantages of the present invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings.
Please refer to
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Next, proceed a bending step, referring to
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In this embodiment the force receiving zone 222 is applied with the punching force through a stamping equipment. Please refer to
Referring to
With the preformed body 20 positioned between the upper mold 41 and lower mold 51, move the stamping head 43 to apply the punching force on the force receiving zone 222, meanwhile the upper mold 41 is moved upwards and escapes the edge portion 223 as shown in
As a conclusion, the method for fabricating wings of bicycle pedals provided by the present invention manufactures the wings in an integrated manner through mechanical processes. Compared with the conventional techniques of adopting soldering or brazing process, the wings formed by the present invention do not have joining interfaces. Hence the structural strength of the wings increases significantly and the life span also lengthens. It also improves safety when in use. Besides, the steps in the fabrication process provided by present invention can all be achieved by stamping, thus is simplified and can make production faster at a lower cost.
While the preferred embodiment of the present invention has been set forth for the purpose of disclosure, modifications of the disclosed embodiment of the present invention as well as other embodiments thereof may occur to those skilled in the art. Accordingly, the appended claims are intended to cover all embodiments which do not depart from the spirit and scope of the present invention.
