The invention relates to a bicycle crank, and more particularly to a bicycle crank that is integrally composed of an L-shaped left crank and an L-shaped right crank incorporated with compression shafts, a cone shaped member and locking members to achieve the bicycle crank having rigidity and durable effect, and a stable entire structure without easily breaking.
Since modern people are very busy, most of them always drive cars for their duties in hurry and are unable to enjoy any leisure activity for relaxing pressures resulted from works. Nevertheless, everybody gradually recognizes the importance of leisure activities on health. Many outdoor scenic spots develop cycling. Bicycles have played an important role in outdoor activities for leisure exercises.
However, a conventional bicycle crank adopts connection manner. As shown in
In addition, according to the disclosed technique of US publication patent US20070295154, entitled as “Crankset Assembly for A Bicycle”, the case disclosed a first crank and a second crank that are symmetry. Connection portions are respectively extended from each one end of the first crank and the second crank. An external periphery at a terminal of the connection portion forms a polygonal cloud portion. An end of a first rotary sleeve is provided for fitting the connection portion of the first crank where another end forms a first wave teeth. A terminal inside the first wave teeth is fit with a first nut having a circular hole. An end of a second rotary sleeve is provided for fitting the connection portion of the second crank where another end forms a second wave teeth that is provided for engaging with the first wave teeth. Moreover, a terminal inside the second wave teeth is fit with a second nut having inner screw holes. A screw bolt is locked to the inner screw hole of the second nut by passing through the circular hole from the first rotary sleeve so as to assemble the first rotary sleeve and the second rotary sleeve as a whole. The shortcomings of the publication structure are shown as the following:
Therefore, to overcome the foregoing shortcomings, the inventor(s) of the invention based on years of experience in the related field to conduct extensive researches and experiments for the crank structure, and finally invented a bicycle crank.
A primary objective of the invention is to provide a bicycle crank, wherein its L-shaped crank is integrally composed of a crank and a connection head to improve the product quality and to achieve solid and durable condition and may not be easily broken. In addition, a compression shaft, a cone shaped member, and locking members are mutually incorporated to ensure that the L-shaped crank can approach the center place of a sleeve to stabilize the entire structure.
A second objective of the invention is to provide a bicycle crank that utilizes a composite material to form an L-shaped crank.
According to the foregoing objectives, the bicycle crank comprises symmetric L-shaped cranks. The symmetric L-shaped cranks are an L-shaped left crank and an L-shaped right crank. Every L-shaped left crank and the L-shaped right crank are integrally formed by a crank and a connection head and each comprise a through hole that passes through the crank and the connection head. A left compression shaft and a right compression shaft are respectively accommodated into the terminals of the through holes of the L-shaped left crank and the L-shaped right crank. An end of a cone shaped member is accommodated to the right compression shaft where another end is accommodated in the left compression shaft. The inner surface of the cone shaped member has screw threads. A rotary sleeve is a hollow shape and integrally formed. One end of the rotary sleeve is connected to the connection head of the L-shaped right crank where another end is connected to the connection head of the L-shaped left crank. The rotary sleeve is used to connect the L-shaped left crank and the L-shaped right crank for connection.
Other features and advantages of the present invention will become apparent from the following description of the invention which refers to the accompanying drawings.
Please refer to
Firstly, as shown in the figures, the bicycle crank 20 of the invention comprises an L-shaped left crank 22 and an L-shaped right crank 24 which are symmetrical. Every L-shaped left crank 22 and the L-shaped right crank 24 comprise a crank 26 and a connection head 28 connected to one end of the crank 26. The crank 26 and the connection head 28 are integrally formed. Another end of the crank 26 is connected to a pedal (not shown in the figure). In addition, an outer periphery of the connection head 28 is a first polygonal cloud portion 30.
Moreover, every L-shaped left crank 22 and the L-shaped right crank 24 each comprises a through hole 32 passing through the crank 26 and the connection head 28. The aperture diameter of the through hole is divided into three parts. The front aperture diameter is A, the aperture diameter of the middle section is B, and the bottom aperture diameter is C, wherein the aperture diameter A is greater than the aperture diameter B, and the aperture diameter C is greater than the aperture diameter C. The through hole 32 forms a positioning flange 34 at the aperture diameter A that is shrunk to the aperture diameter B.
A left compression shaft 36 and a right compression shaft 38 are respectively accommodated to last ends (the aperture diameter C) of the through holes 32 of the L-shaped left crank 22 and the L-shaped right crank 24. An end of the left compression shaft 36 and one end of the right compression shaft 38 each has a plurality of notches 40 to provide proper deformation spaces for the L-shaped left crank 22 and the L-shaped right crank 24.
An end of a cone shaped member 42 is accommodated in the right compression shaft 38 where another end is accommodated in the left compression shaft 36. An inner surface of the cone shaped member 42 has screw threads 44. A rotary sleeve 46 is hollow and integrally formed. An end of the rotary sleeve 46 is connected to the connection head 28 of the L-shaped right crank 24 where another end is connected to the connection head 28 of the L-shaped left crank 22. Inner circumferences of two ends of the rotary sleeve 46 respectively comprises a second polygonal cloud portion 48 corresponding to the first polygonal cloud portion 30 to align the first polygonal cloud portions 30 of the L-shaped left crank 22 and the L-shaped right crank 24. The rotary sleeve 46 connected to the L-shaped left crank 22 and the L-shaped right crank 24 is provided for combining with a driving position of the bicycle. Terminals of two T-shaped locking members 50 have screw threads 52 correspond to the inner screw threads 44 of the cone shaped member 42. The T-shaped locking members 50 respectively pass through the through holes 32, and are locked to two ends of the cone shaped member 42 to connect the L-shaped left crank 22 and the L-shaped right crank 24.
Referring to
In addition, the L-shaped left crank and the L-shaped right crank is integrally composed of a composite material.
The foregoing illustration is the related structures, positions and assemblies of each component of the bicycle crank shown in the invention. Next, the implement effects and the features of the invention expectedly achieved are illustrated as the followings.
Accordingly, the bicycle crank of the invention uses L-type cranks integrally composed of the crank and the connection heads to improve the deformation of the engaging opening caused by using the bicycle crank for long time so as to achieve the rigidity and durable effect, and furthermore the compression shaft, the cone shaped member and the locking members are utilized to ensure that the L-shaped crank can be close to the center of the rotary sleeve to enhance the stability.
Although the features and advantages of the embodiments according to the preferred invention are disclosed, it is not limited to the embodiments described above, but encompasses any and all modifications and changes within the spirit and scope of the following claims.
Number | Date | Country | Kind |
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098213131 | Jul 2009 | TW | national |