Structure for extendable bicycles

Abstract

An improved structure for expandable bicycles to facilitate storing of a bicycle includes a cross bar which has one end fastened to the front fork of the bicycle and a sliding member slidable horizontally on the cross bar to alter the relative position of the front fork and the rear fork. The sliding member has a fastening member to fasten the head and seat of the bicycle on selected locations. Thus the bicycle may be extended as desired and stored conveniently.

Description

FIELD OF THE INVENTION

The present invention relates to an improved structure for extendable bicycles and particularly to a structure that has a sliding member to move a cross bar of a bicycle to alter the relative distance of the front fork and the rear fork to achieve extension desired.

BACKGROUND OF THE INVENTION

In the earlier days bicycles are transport vehicles many people use in work or daily life. These days the bicycle is well developed, and its techniques are quite matured. Besides serving as a transport vehicle, it also is widely used as a recreational instrument, exercise tool, or leisure activity facility rather than a necessary tool of daily life. In countries where population density is high, storage function of the bicycle becomes an important feature to fit the changes of time and people's living environment.

To tackle the bicycle storage problem, the conventional approach adopts folding. While the folding bicycle can reduce the size significantly, the folding procedures are quite complicated. They are not easy for children to do. And the folding joints could injure people if not properly handled. Moreover, the folding joints tended to become loose or damaged after bent for a long period of time.

There are other types of extendable bicycles (referring to FIGS. 1 and 2). One example is to adopt a round cross bar movable in a main frame to achieve extension function. But the single round cross bar tends to turn during sliding. To remedy this problem, another example is to adopt a single but non-circular cross bar slidable in the main frame. While such a design can prevent the cross bar from turning, it is fastened through a pin hole and a pin. Its operation is troublesome. If the pin were lost, the storage function of the bicycle also cannot be done.

SUMMARY OF THE INVENTION

Therefore the primary object of the present invention is to provide an extendable bicycle to facilitate storing. It includes:

• • at least one cross bar which is a portion of the main frame of the bicycle to support and couple all the rest elements of the bicycle. The cross bar is coupled with a first fastening dock and a second fastening dock on the front end and the rear end. The first fastening dock on the front end has a first bore to install the front fork of the bicycle;
  • a sliding member which has a second bore formed on the side wall and a third bore on the top side. The second bore allows the cross bar to run through and sliding therein. The third bore aims to install the rear fork; and
  • a fastening member which includes a fastening plate and a fastening rod. The sliding member has a first fastening hole to couple the fastening member and the sliding member. The fastening plate has a second fastening hole to install the fastening rod.

Another object of the invention is to improve the complicated storing procedures of the conventional folding bicycles, and the risk of injuring people caused by the folding joints and the concern of easily damage occurred to the folding joints.

Yet another object of the invention is to improve the operation of the extension mechanism of the extendable bicycle.

The foregoing, as well as additional objects, features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a conventional extendable bicycle.

FIG. 2 is a schematic view of another conventional extendable bicycle.

FIG. 3 is an exploded view of the present invention.

FIG. 4 is a perspective view of the invention.

FIG. 5 is a schematic view of an embodiment of the present invention.

FIG. 6A is a schematic view of an embodiment of the present invention in an operating condition.

FIG. 6B is a schematic view of an embodiment of the present invention in another operating condition.

FIG. 7 is a schematic view of a second embodiment of the present invention.

FIG. 8 is a schematic view of a third embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Please referring to FIGS. 3, 4 and 5, the present invention includes an extension mechanism 1 which has at least one cross bar 10 to become a portion of the main frame of a bicycle to support and couple all the rest elements of the bicycle. The cross bar 10 is coupled with a first fastening dock 11 on the front end and a second fastening dock 11′ on the rear end. The first fastening dock 11 has a first bore 110 to install a front fork 12 of the bicycle. A sliding member 13 is provided that has a second bore 130 formed on the side walls thereof to allow the cross bar 10 to run through. The second bore 130 has two openings on two ends each is coupled with a ball bearing 25 to facilitate sliding of the cross bar 15. The sliding member 13 further has a third bore 131 on the top side to install a rear fork 14.

There is a fastening member 15 which includes a fastening plate 150 and a fastening rod 151. The sliding member 13 has a first fastening hole 132 to couple the fastening member 15 and the sliding member 13. The fastening plate 150 is wedged in a trough 23 formed on the sliding member 13 in a corresponding shape. The fastening plate 150 has a second fastening hole 152 to couple the fastening rod 151 with the fastening plate 150. The fastening plate 150 has a recess 24 matching the shape of the cross bar 10 run through the sliding member 13.

The fastening docks 11 and 11′ have respectively a fourth bore 16 and a fifth bore 17 formed on one side wall to couple with the cross car 10. The locations of the fourth and fifth bores 16 and 17 correspond to the number and shape of the cross bar 10. The junctures of the fastening docks 11 and 11′ and the cross bar 10 have respectively an elastic element 19 to reduce impact and damage caused by sliding. The fastening docks 11 and 11′ further have respectively a third fastening hole 22 to receive a fastening element 18 to fasten the cross bar 10 in the fastening docks.

Referring to FIGS. 5, 6A and 6B, to extend or retract the bicycle through the extension mechanism 1, first, unfasten the fastening rod 151 at a first position, the fastening plate 150 moves downwards without forming a tightly coupling with the cross bar 10 and the sliding member 13; and the cross bar 10 may be moved and slid on the sliding member 13 to shrink the distance between the front fork 12 and the rear fork 14 at a second position; then depress the fastening rod 151. As the fastening rod 151 includes a cam handle, through the cam mechanism, the fastening plate 150 can be moved to clamp the cross bar tightly again to fix the position.

Refer to FIGS. 7 and 8 for other embodiments of the invention. The sliding member 13 is coupled on sliding tracks 20. Four bearings are provided on the coaxial locations of two sides of the top section of the sliding member 13 (referring to a second embodiment), or on the coaxial locations of two side walls of the sliding member 13 (referring to a third embodiment). The sliding tracks 20 are located on the upper side and the lower side of the sliding member 13, or on the left side and the right side of the sliding member 13. By means of the process previously discussed, the relative distance between the front fork 12 and the rear fork 14 may be altered.

While the preferred embodiments of the invention have been set forth for the purpose of disclosure, modifications of the disclosed embodiments of the 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 invention.

Claims

1. An improved structure for expandable bicycles for use on a main frame of a bicycle to extend or retract the bicycle by altering the relative position of a bicycle head, comprising:

at least one cross bar which is a portion of the main frame for supporting and coupling all other elements of the bicycle having a first fastening dock on a front side and a second fastening dock on a rear side, the first fastening dock having a first bore for installing a front fork;

a sliding member having a second bore on side walls thereof to allow the cross bar to run through and slide therein, a third bore on a top side to install a rear fork, and a first fastening hole; and

a fastening member including a fastening plate and a fastening rod, the fastening plate being coupled with the sliding member through the first fastening hole, the fastening plate having a second fastening hole corresponding to the first fastening hole to install the fastening rod.

2. The improved structure for expandable bicycles of claim 1 further having an elastic element located on the juncture of the cross bar and each fastening dock to absorb impact when the sliding member slides on the cross bar.

3. The improved structure for expandable bicycles of claim 2, wherein the elastic element is a soft pad or a spring.

4. The improved structure for expandable bicycles of claim 1, wherein the first fastening dock and the second fastening dock have respectively a fourth bore and a fifth bore on a side wall thereof to couple with the cross bar for fastening.

5. The improved structure for expandable bicycles of claim 1, wherein the cross bar is fastened to the fastening dock through a fastening element.

6. The improved structure for expandable bicycles of claim 5, wherein the fastening element is a screw or an anchor nail.

7. The improved structure for expandable bicycles of claim 5, wherein the fastening docks have a third fastening hole.

8. The improved structure for expandable bicycles of claim 1, wherein the sliding member has a trough mating the fastening plate to couple with the fastening plate.

9. The improved structure for expandable bicycles of claim 1, wherein the fastening plate has a recess mating the cross bar run through the sliding member.

10. The improved structure for expandable bicycles of claim 1, wherein the fastening rod has a coupling section on the bottom thereof to fasten the fastening plate, the cross bar and the sliding member and close gaps formed therebetween to anchor the sliding member on a desired location.

11. The improved structure for expandable bicycles of claim 10, wherein the coupling section is a bolt or a latch tenon.

12. The improved structure for expandable bicycles of claim 1, wherein the fastening rod has a cam on the top end thereof which is eccentric to fasten the fastening plate, the cross bar and the sliding member tightly.

13. The improved structure for expandable bicycles of claim 1, wherein the second bore has two openings on two sides to hold respectively a ball bearing or a roller to facilitate sliding of the cross bar.