Crank arm remover for a bicycle

The present invention relates to a crank arm remover for a bicycle, which includes a screw bolt and a threaded sleeve. The screw bolt is provided at an end with a corner portion which is to be pushed by a grip handle, another end of the screw bolt is provided with an abutting block. The threaded sleeve is screwed on the screw bolt. The characteristics of this present invention are that the abutting block has more than one layer of abutting portion, and the respective layers of abutting portion have different sizes. By such arrangements, this crank arm remover will be operable to assemble and disassemble the crank arm of different sizes.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a crank arm remover for a bicycle, and more particularly to a crank arm remover for a bicycle that is applicable to at least two different types of crank arm of a bicycle.

2. Description of the Prior Arts

Referring toFIG. 1, a conventional crank arm remover for a bicycle generally comprises a screw bolt11and a threaded sleeve12. At an end of the screw bolt11is provided a corner portion111which is to be rotated and engaged by a grip handle13. Another end of the screw bolt11is formed with an abutting block112. The threaded sleeve12is provided on its outer surface with plural threads121. The threaded sleeve is moveably installed on the screw blot11and located between the corner portion111and the abutting block112. As shown inFIG. 2, to remove a crank arm of a bicycle, the user can start by screwing the threads121of the threaded sleeve12in a threaded hole211of the crank arm21and engaging the grip handle13with the corner portion111of the screw bolt11, at this moment, the threaded sleeve12and the crank arm21are locked with each other, and then pushing the grip handle13so as to make the screw bolt11move toward the central rotation axis22until the abutting block112of the screw bolt11pushes against the central rotation axis22. Thus causing the crank arm21to be pushed by the threaded sleeve12to move backward and finally disengage from the central rotation axis22. However, this crank arm remover still has some disadvantages in real operation:

The threaded sleeve12needs to be locked with the crank arm21if want to remove the crank arm21, and the abutting block112of the screw bolt11needs to move to and push against the end surface of the central rotation axis22. However, there is another type of crank arm that the central rotation axis22and the crank arm21are screwed with each other, as shown inFIG. 3. This type of central rotation axis22and the crank arm21cannot be pushed by the abutting block112of the screw bolt11(namely, an axial hole221of the central rotation axis22is larger than the abutting block112of the screw blot11), it needs to use another type crank arm remover to remove the crank arm, thus, the conventional crank arm remover for a bicycle is not so practical.

SUMMARY OF THE INVENTION

The primary object of the present invention is to provide a crank arm remover for a bicycle which is applicable to at least two different types of crank arm of a bicycle.

A crank arm remover for a bicycle in accordance with the present invention comprises:

a screw bolt, at an end of which is formed a corner portion employed to be engaged and rotated by a grip handle, at another end of the screw bolt is pivotally disposed an abutting block;

a threaded sleeve is moveably installed on the screw bolt;

wherein the abutting block includes a first abutting portion and a second abutting portion, the first abutting portion projects from a central part of an abutting surface of the second abutting portion, and an abutting surface of the first abutting portion is smaller than that of the second abutting portion, thus, the crank arm remover for a bicycle is applicable to at least two different types of crank arm.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring toFIGS. 4 and 5, a crank arm remover for a bicycle in accordance with the present invention comprises: a screw bolt30, a threaded sleeve40and an abutting block50.

At an end of the screw bolt30is formed a hexagonal-shaped corner portion31which is to be engaged and rotated by a grip handle32, at another end of the screw bolt30is defined a groove33.

The threaded sleeve40is provided at its outer surface with plural threads41for meshing with the screw bolt30.

The abutting block50includes a first stepped abutting portion51and a second stepped abutting portion52. The first stepped abutting portion51projects from the center of an abutting surface521of the second stepped abutting portion52, an abutting surface511of the first stepped abutting portion51is smaller than the abutting surface521of the second stepped abutting portion52. Furthermore, an axial hole53passing through the first and the second stepped abutting portions51,52is interiorly provided with a pivot54having a head portion541which rests against the shoulder portion531of the axial hole53. The body portion542of the pivot54is inserted in the groove33of the screw bolt30after passing through the axial hole53. Thus, the abutting block50is pivotally disposed at the second end of the screw bolt30.

Referring toFIGS. 6 and 7, after the threads41of the threaded sleeve40are screwed in the threaded hole211of the crank arm21, the user can rotate the corner portion31of the screw bolt30with the grip handle32, thus moving the abutting block50toward the central rotation axis22until the first abutting surface511of the first stepped abutting portion51abuts against the end surface of the central rotation axis22. Thus, the crank arm21will be pushed by the threaded sleeve40to disengage the central rotation axis22.

Referring toFIGS. 8 and 9, which show another type of central rotation axis22and crank arm21, wherein the central rotation axis22are screwed with the crank arm21. An axial hole221of the central rotation axis22is larger than the abutting surface511of the first abutting portion51of the abutting block50. To remove the crank arm21, the user also screws the threads41of the threaded sleeve40in the threaded hole211of the crank arm21, and then rotates the corner portion31of the screw bolt30with the grip handle32, thus pushing the abutting block50to move toward the central rotation axis22. At this movement, the first abutting portion51will move in the axial hole221of the central rotation axis22until the abutting surface521of the second abutting portion52of the abutting block50abuts against the end surface of the central rotation axis22. Thus, the crank arm21will be caused to move opposite to the threaded sleeve40and finally disengage from the central rotation axis22.

Thereby, the present invention is improved in applicability since it is applicable to the two different types of crank arms of a bicycle. Besides, the abutting block50in accordance with the present invention can be provided with multiple layers of abutting portion, and the abutting surfaces of the respective layers of abutting portion are different in size. Thus, it can be applicable to multiple types of crank arm and central rotation axis.

Referring toFIG. 10, a crank arm remover in accordance with a second preferred embodiment of the present invention generally comprises: a screw bolt30, a threaded sleeve40and an abutting block50. Its structure and operating manner are identical to the crank arm remover of the first embodiment, so further explanations will be omitted here, and only the differences are explained as follows:

At an end of the screw bolt30opposite to the corner portion31is formed a pivot portion34whose terminal end is provided with a flange341. The pivot portion34is hollow and slightly deformable after compression. The abutting block50includes three layers of abutting portion, and the abutting-surfaces of the respective layers of abutting portion are different in size. Furthermore, the abutting block50is axially defined with a flute551which is provided on its sidewall with a cavity551. Thus, the abutting block50can be pivotally installed on the screw bolt30by special means in such a manner that the flange341is engaged in the flute551.