GB2232390A - Foldable multipurpose bicycle/amphibian - Google Patents

Abstract

A foldable multipurpose bicycle wherein the main frame 10 thereof can be folded up, and the saddle 80 and both wheels 80 can be disassembled whereby the disassembled two wheels 180 can be replaced with a float assembly and a propeller assembly see Fig. 59 to form a hydro-bicycle whereby the propeller is driven by the pedals and the direction is controlled by rotation handlebars 131, 132 which steer in turn the propeller/rudder assembly 250. When used on the land, a wheel support can be mounted on the rear portion of the main frame 10, permitting the rear wheels to be attached, forming a tricycle (not shown) or two leg supports can be mounted respectively on the front and rear ends of the main frame 10 to form an exercise bicycle (not shown). In the folded mode, the two wheels 180 are detached from the main frame and are rotatably mounted either side of the folded assembly on a bar passing therethrough to form a relatively small wheel like unit capable of being easily rolled on the ground Fig. 57 (not shown). <IMAGE>

Description

SPECIFICATION FOLDABLE MULTIPURPOSE BICYCLE The prevent invention relates to new and useful improvements in an amphibious bicycle, and more particularly to one which can be adjusted quickly into the form of a bicycle for riding on land which can be folded quickly into a relatively small portable unit, a hydro-bicycle for riding on smooth surfaces of water, a tricycle and an exercise bicycle for riding in a fixed position.

It is known that conventional amphibious bicycles can not be folded Intc a small portable unit due to their com,plicated structure. In addition, because of the manner In which the frame members are jointed they cannot be folded or unfolded quickly or efficiently by one individual.

Furthermore, the main problem of a conventional foldable amphibious bicycle with a large size frame and float structure is that it cannot be separated and folded for storage and transport.

An object of the present invention is to provide an amphibious bicycle which can be folded quickly into a relatively small portable unit.

Another object of the present invention is to provide a foldable amphibious bicycle which can be folded and unfolded quickly, easily, and efficiently by one individual.

Still another object of the present invention is to provide a foldable amphibious bicycle which can be adjusted into the form of an exercise bicycle for riding in a fixed position.

According to the present invention, the foldable multipurpose bicycle includes a foldable main frame, a foldable handlebar assembly, a removable seat assembly, a foldable left pedal assembly5 a foldable right pedal assembly, a removable front wheel assembly, a removable rear wheel assembly, a front brake assembly, a rear brake assembly, a removable float assembly, a removable propeller assembly, two removable quick-release lock mechar.isms,a removable article holder, two removable leg support assemblies a removable wheel support, and a removable additional rear wheel.

The front wheel and the rear wheel according to the present invention are of the same standard size so that they are interchangeable.

After the main frame, handlebar assembly, seat assembly, left and right pedal assemblies, front and rear brake assemblies are quickly assembled together, by using the quick-release lock mechanisms, the main frame can be incorporated with the front and rear wheel assemblies to form a bicycle for riding on the land. While when this bicycle is idle, it can be folded quickly into a relatively small wheel-like portable unit which is convenient and easy to store.

In addition, the front and rear wheels can be replaced with the float assembly and propeller assembly to for a hydro-bicycie for riding on smooth surfaces of water.

Also, b using the quick-release lock mechanism, the main frame can be incorporated with leg support assemblies to form an exercise bicycle for riding in a fixed position.

Furthermore, the rear wheel can be replaced with the wheel support, and the replaced rear wheel and additional rear wheel can be rotatably mounted on two ends of the wheel support to form a tricycle.

The present invention shall be further described with reference to the accompanying. drawings in which: Fig. 1 is a perspective view of a foldable bicycle according to the present invention; Fig 2 is an elevational right side view of the foldable bicycle; Fig. 3 is an elevational left side view showing a main frame of the foldable bicycle; Fig. 3A is an exploded view of the article holder of the present invention; Fig. 3B is a sectional view of the article holder of the present invention; Fig. 4 is a schematic view showing a steering column structure of the foldable bicycle; Fig. 5 is a perspective view showing an upper diagonal brace of the foldable bicycle; Fig. 6 is a perspective view showing the upper diagonal brace of the foldable bicycle in a folded position;; Fig. 7 is a schematic side view showing the upper diagonal brace of the foldable bicycle; Fig. e is schematic bottom view showing the upper diagonal brace of the foldable bicycle; Fig. 9 is a perspective view showing a lower diagonal brace of the foldable bicycle; Fig. 10 is a schematic view showing a horizontal member of the foldable bicycle; Fig. 10A Shows an alternative horizontal member of the foldable bicycle; Fig. 11 is a perspective view showing a seat assembly of the foldable bicycle; Fig. 12 is a schematic view illustrating the engagement of key and keyway between a leading upper tube and a seat supporting rod of the seat assembly;; Fig. 13 is a schematic view IllustratIng how a seat lock bar inter locks the leading upper tube and the seat supporting rod, in which the solid lines show an unlocking position; Fig. 14 is a schematic view showing a saddle member and the seat support rod of the foldable bicycle; Fig. 15 is a schematic view illustrating how the saddle member is attached to the foldable bicycle in a molded position; Fig. 16 is a front view of the foldable bicycle; Fig 17 is a perspective view showing a front brake assembly of the foldable bicycle; Figs. 18 and 19 are schematic views illustrating the operation of the front brake assembly; Fig. 20 is a side view showing a rear brake assembly of the foldable bicycle; Fig. 21 is a schematic view illustrating how the rear brake assembly is positioned;; Fig. 22 is a schematic view illustrating the engagement between a square socket of a sliding outer type and a square adapter of an inner tube of the rear brake assembly; Fig. 23 is a schematic view showing the rear brake assembly in an adjusted position; Figs. 23A and 23show another embodiment of the rear brake assembly of the present invention; Fig. s is a. schematic view showing a handlebar assembly of the foldable bicycle; Fig. 25 is a schematic view showing the handlebar assembly in a folded position; Fig. 26 is a schematic top view illustrating the relationship between two handlebars and a handlebar fitting of the handlebar assembly; Fig. 27 is a schematic front view of the handlebar assembly;; Fig. 28 is a schematic right side view showing a handle lock mechanism of the foldable bicycle in a locking position; Fig. 29 is a schematic left side view showing the handle lock mechanism in an unlocking position; Fig. 30 is a perspective view of the handlebar spindle; Fig. 31 is a perspective view showing s left pedal assembly cf the foldable bicycle; Fig. 32 is a schematic view illustrating the adjustment of the left pedal assembly; Fig. 33 is a perspective view showing the left pedal assembly of the foldable bicycle in a folded position; Fig. 34 is a schematic perspective view Illustrating how to adjust a right pedal assembly of the oldie bicycle; Fig. 35 is a perspective view of the right pedal assembly of the foldable bicycle;; Fig. 38 is a schematic view illustrating the relationship between an extension rod and a pedal fitting of the right pedal assembly in an operative position; Fig. 7 is z schematic view illustrating the relationship between the extension rod and the extension rod and the pedal fitting of the right pedal assembly in an actuated position; Fig. 38 is a schematic side view illustrating the adjustment of the right pedal assembly; Fig. 39 is a schematic perspective view illustrating the attachment of a quick-release lock mechanism between a wheel shaft and a wheel hub of the foldable bicycle; Fig. 40 is a perspective view showing an end portion of the wheel shaft; ; Fig. 41 is a perspective view showing the quickrelease mechanism of the foldable bicycle; Figs. 42 and 43 are schematic vieus Illustrating the operation of the quick-release lock mechanism; Fig.44 shows another embodiment of the quickrelease lock mechanism, wheel shaft and wheel hub assembled together; Fig. 45 shows another embodiment of an end potion of the wheel shaft; Fig. 46 shows a second embodiment of the quickrelease mechanism of the present invention; Fig. 47 is an exploded view according to Fig. e; Figs. 48 and 4C show the adjustment of the second embodiment of the quick-release mechanism;; Fig's. 50 tc 52 are schematic views Illustrating how the integral mounted pats of the foldable bicycle are folded to form a generally triangular small unit; Fig. 53 is a perspective view showing a wheel connecting rod attached to the saddle member of the foldable bicycle; Fig. 54 is a perspective view showing a clip provided for holding the wheel connecting rod on the saddle member; Fig. 55 is an exploded view of the wheel link of the present invention; Fig. 56 shows the operation position of the wheel link according to Fig. 55; Fig. 57 is an elevational view of the wheel-like unit; Fig. 58 is a perspective view showing the foldable bicycle which has been folded into a wheel-like unit;; Fig. 59 is a perspective view showing a hydrobicycle which is formed from the foldable bicycle of the present invention; Fig. 60 is rear elevational view showing propeller assembly of the hydro-bicycle; Fig. 61 is a schematic side view of the propeller assembly; Fig. 62 is a sectional view of the retainer mechanism of the propeller assembly of the hydro-bicycle of the present invention; Fig 83 is a perspective view ol the rudder cable assembly cf the present Invention; FIg. 64 is a plane view of the cable controller of the hydro-blcycle of the present invention; FIg. 65 is a top elevation of the rudder cable of the present inventIon;; Fig. 66 is a perspective exploded view of the leg support and metal ring of the present invention; Fig. 67 is a perspective view of the present invention in an exercise bicycle form; Fig. 68 is an exploded view of the friction means of the exercise bicycle of the present invention; Fig. 69 is is a perspective view of the present invention in tricycle form; Fig. 70 shows the wheel support of the tricycle according to Fig. 69; and Fig. 71 shows the connection of the wheel support of the tricycle the rear wheel shaft.

Referring to Figs. 1 and 2, there is shown a foldable bicycle for riding on land, which is a first form of the present invention. As illustrated, the foldable bicycle is supported by a pair of wheels 180 and a hingedly mounted stop support 43. This bicycle includes a single front fork 161 and a main frame 10,as shown in Fig. 3, which consists of a front frame portion 90 and a rear frame portion 20. The front frame portion 90 includes a steering outer column 126. an upper diagonal brace 85 secured to the steering outer column 126 and hinged to the rear frame portion 20,a lower diagonal brace 110. secured to the steering outer column 196, and a front inclined tube 98 hinged to the lower diagonal brace 110.The front frame Portion 9G looks iiae a quadranùlar truss. A steering inner column 121 is mounted rotatably in the steering outer column 126 by ball bearings 122, as shown in Fig. 4.

Referring to Fig. 3 with reference to Fig. 5, the upper diagonal brace 85 includes a front tube 91, a middle tube 95, and a rear tube 101. The meddle tube 95 is hinged to the front tube 91 by a first center hinge 93 and to the rear tube 101 by an over-center hinge 98.

With particular reference to Figs. 6 to 8, to achieve the over-center hinged joint, the rear end of the middle tube 95 is formed with a first square outward flange 96 and the front end of the rear tube 101 is likewise formed with a second square outward flange99 which is hinged to the first flange 96 by the over-center hinge 98 at the lower end thereof. Furthermore, to interlock the first flange 9E and the second flange 99, the rearward surface of the first flange 96 has a tapered bore B and the forward surface of the second flange 99 has a bore through which a well-matched taper latch 97 extends.The latch 97 is biased to move toward the tapered bore B by a compression spring 107 which is positioned by a trigger screw 106 is adjusted from the position shown in the solid lines of Fig. 7 to the position shown in the phantom lines of Fig.7 along a slide slot 108 so that the bias force of the compression spring 107 is released The middle tube 5 is then rotated relative to the rear tube 101 so that the latch 97 fully disengages from.

the tapered bore B of the middie tube 95. When it is desired to unfold the folded upper diagonal brace 8=; the middle tube 9 is restored to align with the rear tube 101.

The trigger screw 106 is then returned to the position shown in the solid lines of Fig. 7 so that the taper latch 97 is biased to insert into the bore B, thereby interlock the middle tube 95 and the rear tube 101.

As illustrated, the rear tube 101 is hinged to the rear frame portion 20 by a bolt 104 and a nut 105.

Referring to Fig. 9, the lower diagonal brace 110 is bent. The front inclined tube 28 is hinged to the lower diagonal brace 110 by a second center hinge 111. Two inclined through holes 109 are provided in the lower diagonal brace 110.

Again referring to Fig. 3, the rear frame portion 20 includes a horizontal member 21, a leading lower tube 23, a leading upper tube 24. a tailing edge tube 26, a horizontal tube 25 a rear vertical tube 26A, and a rear brake assembly 50. It looks like a triangular truss.

Provided in the horizontal type 25 are a transverse through hole 30, a longitudinal through hole 46, and a thread hole 31.

Please refer to Figs. 3A and 3B. An article holder 51 is connected to the horizontal tube 25 by a support rod 250. The lower end of the support rod 250 is provided with an arch abutment 250A having a lower stud portion. When the bolt portion is extended through a traverse hole 46 of the horizontal member 25, the abutment 950.E abuts against the horizontal member 25 whereby a nut 252 can be screwed on the bolt portion to secure the support rod 5rut te the horizontal member 25.

The upper end of the support rod 250 is formed with traverse tube portion 250B having an upper stud portion 250C. WHile the article holder 251 is provided with a rotary nut 253 and a lower abutment 254 whereby by means of rotating the rotary nut 253, the upper stud portion 250C is screwed on the rotary nut 253 to secure the abutment 254 to the traverse tube portion 250B of the support rod 250.

Referring to Fig. 10, fixed on the horizontal member 21 are a main hub 22 in which a main sprocket shaft 32 is journalled on ball bearings 38, and a rear hub 27 in which a rear wheel shaft 163 is journalled on ball bearings 34. A main sprocket 39 is mounted on the main sprocket shaft 32, and a driven sprocket 39A is mounted on the rear wheel shaft 163.

Referring to Fig. 11 ith reference to Figs. 12 to 14, a rear assembly 70 includes the leading upper tube 24, a saddle member 80, a seat supporting rod 75 secured to the saddle member 80 and movable within the leading upper tube 24, and a seat lock bar 72 mounted rotatably on the leading upper tube ?' for Inter locking the leading upper tube 24 and the seat supporting rod 75.

Referring to FIg. 12, the seat supporting rod 75 is formed with an elongated keyway S, while the leading upper tube 24 is formed with a key strIp Y; engaged with the keyway S for preventing the relative rotation between the leading upper tube 2.4 and the seat supporting rod 75. The seat supporting rod 75 is formed with equally spaoed concavities 81 e:tendIng lengthwise therein.The sest lock bar 72 includes an engagement end E biased by a torsion spring 76 t see Figs. 11 and 13 ) to abut against the seat supporting rod 75, and the opposite end with a knob 71 screwed thereto which is capable of being driven to disengage the engagement end E form the seat supporting rod 75, as shown in the phantom lines of Fig. 13. When the engagement end E of the seat lock bar 72 engages with any of the concavities 81 of the seat supporting rod 75, the relative movement between the leading upper tube 24 and the seat supporting rod 75 is prevented. Accordingly, the height of the saddle member 80 is adjustable.It should be noted that a tongue 79 ( see FIg. 11 ) is secured between the saddle member 80 and the seat supporting rod 75, and a groove member 78 cm see Fig. i4 ) is provided on the leading upper tube 24 for engaging with the tongue 79.

Referring to Fig. 15, when the bicycle is folded, the removed saddle member 80 may be attached to the leading upper tube 24 by the engagement of the tongue 79 with the groove member 76 as shown in Fig. 15.

Referring to Fig. 16 to 19, a front brake assembly iO includes a lining 151 mounted on the lower end of a slide sleeve M which is mounted movably with the steering nner column 121. As Illustrated, the slide sleeve M is provided 'v17 Gr. a pair of opposed slide slots N through which 8 bolt i C is passed after a compression spring 154 is inserted into the slide sleeve X above the slide slots N.

The bolt C is also passed through the steering inner column 1211 Sc that the slide sieeve H Is biased by the compression spring 154 to move upwardly. A nut 153 engages with the bolt C to an extent in such a manner that the bolt C can rotate. Secured to the head of the bolt C is a cam 152 with a swing arm 155 which is connected securely to a front brake cable 158 and which is normally positioned in proximity to the lining 151, as shown in Fig. 18. When the front brake cable 158 is pulled upwardly, the cam 152 rotates clockwise to push the lining 151 downwardly to press over the front wheel1 as shown in Fig. 19. It can be understood that this front brake structure is less complex than the conventional structure.

Referring to Figs. 20 to 23, the rear brake assembly 50 includes an inner tube 51 secured to the horizontal tube 25 and having a square adapter 59 secured to te shoulder thereof a middle tube 54 fixed on the inner tube 51 by three screws 55, a sliding outer tube 52 mounted slidably on the inner tube 51 and on the middle tube 54, and a compression spring 53 disposed between the middle tube 54 and the sliding outer tube 52 for biasing the sliding outer tube 52 to move downwardlyrdly. With particular reference to Fig. 20, a rear lining assembly 57 is secured to the sliding outer tube 52 by a rear brake fitting 56.

Normally. the square adapter 59 of the inner tube 51 engages with the square socket 55 of the sliding outer tube 52, as shown in Figs. 21 and 22.. so that the rear lining assembly 57 is positioned in its operative position, as shown in Fig.

When Wher. the bicycle is Idle, the sliding outer tube 52 may be. pushed upwardly tic; separate the square socket 58 from the square adapter 59 so that the sliding outer tube 52 carryIng the rear lining assembly 57 is rotated to the right side of the main frame 10, i.e. its folded position. After the sliding outer tube 52 is rotated to the folded position, so long as the gripping force to the sliding outer tube 52 is released, the sliding outer tube 52 will be biased by the compression spring 53 to move downwardly until the square socket 58 engages with the square adapter 59. It is apparent that the operation of folding the rear brake assembly 50 is quite simple, and vice versa, the unfolding operation is also very simple.

Please refer to Figs. 10A, 23A and 23B. The rear brake assembly can be alternatively arranged, wherein a disk is fitted to the rear wheel shaft 163 whereby when the brake cable disposed on the left handlebar is pulled manually, the brake lining b is urged by a rotary arm B to inward press against the periphery of the disk D and brake the bicycle via frictional force.

Referring to Figs. 24 and 25 with reference to Figs. 26 to 30, a handle assembly 130 includes a left handlebar 131, 8. right handlebar 132, a handlebar fitting 135 mounted on a nandle column 133 by an adjust screw 142, and a handle lock mechanism 134. The left handlebar 131 and right handlebar 132 are hinged by 8 pair of hinges 137 to opposite ends of a handlebar spindle 135 which is journailed on the handlebar fitting 135. The handlebar spindle 136 has at the riddle thereof an annular guide slot G with a stop G, as shown In Fig. 30. Inserted into the guide slot W is a guide screw 143 which is fixed on the handlebar fitting 135 by a nut 1A4, as shown in FIgs. 28 and 29.

The handle lock mechanism 134 will be described hereinafter. A pair of guide rods 145 are secured to the handlebars 131 and 132 respectively. The handlebar fitting 135 has at the front thereof a pair of aligned transverse guide slots H for receiving the guide rods 145. When the guide rods 145 are received within the guide slots H, the curved upper cover of a T-shaped hook 138 ( see Figs. 28 and 29 ) can be moved by hand onto the guide rods 145, as shown in Fig. 29. With particular reference to Fig. 27, the Tshaped hook 138 is connected rotatably to a rotatable cam rod 139 on which a retaining ring 140 and a handlebar lock bar 141 screwed through the ring 140 are fixed.When the handlebar lock bar i4i is turned downwardly, as shown in Fig. 28. the T-shaped hook 183 is driven to move downwardly and in turn to lock the guide rods 145 within the transverse guide slots H. When the guide rods 145 are locked within the transverse guide slots H, the handlebar spindle 136 and handlebars i31 and 132 can not rotate, thereby forming an operative position.

When it is desired to fold the bicycle, the Tshaped hook 138 is released from the guide rods 145 by turning the handlebar lock bar 141 upwardly. After the Tshaped hook 138 is released, the handlebars 131 and 132 are turned to the front and then folded together, as shown in Fig. 25, thereby forming a folded condition. It is noted that the stop G of the handlebar spindle 136 can restrict the handlebar spindle 136 and hence the handlebars 131 and 132 to rotate within a limited range of angle, which is slightly smaller than 200 degrees. Because the rotational angle range of handlebars 131 and 132 is smaller than 200 degrees, the front brake cable 158 attached to the handlebars 131 and 132 can not be twisted.

Referring to Figs. 31 to 33, there is shown a left pedal assembly 190. It includes a left pedal 191 and a left pedal link 192 connecting the left pedal 191 and a to the main sprocket shaft 32. The left pedal link 192 is hinged to the main sprocket shaft 32 by a bolt 197 and a nut 198. A cam latch 196 is fit to fully occupy the space between the left pedal link 192 and the main sprocket shaft 3 for hindering the left pedal link 192 from rotation relative to the main sprocket shaft 32 on a horizontal plane. The cam latch 196 is hinged to the left pedal link 192 by a hinge 194. In addition, the cam latch 196 has a crank arm which is pulled by a torsion spring 193, which is hinged to the left pedal link 192 by a screw 195, to fully occupy the space between the left pedal link 192 and the main sprocket shaft 32.

When it is desired to fold the bicycle, the crank arm of the cam latch 196 is moved away from the torsion spring 193 so that the cam latch 196 separates partially from the space between the left pedal link 192 and the main sprocket shaft 32, as shown in Fig. 32. The left pedal link 1 is then rotated through 180 degrees to the position shown in Fig. 33. When use of the folded left pedal assembly 190 is desired, the left pedal link 192 is rotated to the original position. Then, the crank arm of the cam latch 196 is pushed into the curved free end of the torsion spring 193 so that the cam latch 196 returns to its operative position, as shown in Fig. 31.

Referring to Figs. 34 to 38, there is shown a right pedal assembly 200. It includes a right pedal 201 provided with a transverse extension rod 207. Aright pedal link 208 is provided with a pedal fitting 206 which has an open-ended transverse slot. The end portion of the transverse extension rod 207 is received in the transverse slot of the pedal fitting 206 and hinged at the distal end to the right pedal link 208 by a hinge bolt 204. The pedal fitting 206 has a rounded upper edge facing the right pedal 201, as shown in Figs. 36 to 38. Sleeve on the transverse extension rod 207 are a slide sleeve 203 formed with an inward flange, and a compression spring 202 for biasing the slide sleeve 203 to sleeve on the pedal fitting 206, as shown in Figs. 35 to 37, so as to prevent the rotation of the extension rod 207 relative to the pedal fitting 206 in use.

When it is desired to fold the right pedal assembly 200, the slide sleeve 203 is moved manually away form the pedal fitting 206 so that the compression spring O is compressed, as shown in Fig. 37. The transverse extension rod 207 is then rotated through 90 degrees about the hinge 204 to a vertical position, as shown in the phantom lines of Figs. 34 and 38. When the transverse extension rod 207 arrives at the vertical position, the slide sleeve 203 is released to be biased by the compression spring 202 to sleeve on the pedal fitting 206 forming a folded position. It is understood that the rounded upper edge of the pedal fitting 206 makes the rotation of the transverse extension rod 207 very easy.

The front and rear wheels of the present invention is fastened to the main frame by two identical quick-release lock mechanism. Referring to Figs. 39 to43, the end of the rear wheel shaft 163 is formed with two L-shaped end portions 167 which define a T-shaped groove 168. While a quick-release lock assembly 170 is disposed on the end surfaces of the rear wheel hub 181. The quick-release lock assembly 170 includes a clamp member 171 having a rotary arm 17 pivoted on a pivot shaft 172', a sleeve body 173, a clamp arm 174 and a L-shaped eccentrical member 175. The clamp arm 174 has a cylinder portion received in the cylinder body 173. An adjustment nut-lids clamp plate 174 is screwed on the thread end of the clamp q4m 174.The cylinder portion of the clamp arm 174 and the sleeve body 17 are formed with through holes through which the eccentric member 175 goes to be secured to the sleeve body 173 by a nut 176.

The end surface of the rear wheel hub 181 is formed with a square hole H1 having an arch extension slot H2. The clamp plate 1.4 of the damp member 171 is received in the slot, permitting the clamp member 171 to move within the slot H2 and square hole H1. When the rear wheel hub is fitted on the rear wheel shaft 163, both end surfaces thereof are almost flush with each other. In this position, the eccentrical member 175 cam be pulled away from the end surface of the rear wheel hub 181 to separate the cylinder portion of the slamp arm 174 from the end surface of the rear wheel hub 181, permitting the clamp arm 174 to move along the slot H2. Consequently, the clamp plate 174 enters the T-shaped groove 168 of the rear wheel shaft 163.

Thereafter, the eccentrical member 175 can be rotated to a position parallel to the end surface of the rear wheel hub 181, as shown in Fig. 39,to move the eccentrical portion 177 of the eccentrical member 175 to the right side. As a result, the clamp plate 174' is moved to the right side to cooperate with the sleeve body 173 for closely clamping the -shaped end portions 167 of the rear wheel shaft 183, and thus securing the rear wheel hub 181 to the rear wheel shaft 163.

As a result, the clamp plate 174 is moved to the right side to cooperate with the sleeve body 173 for closely clamping the L-shaped end portions 167 of the rear wheel shaft iC3, and thus securing the rear wheel hub 161 to the rear wheel shaft 163.

Tc remove the clamp member 171 from the T-shaped groove 168, the eccentric member 175 can be rotated to the other side of the rear wheel hub 181, as shown in Fig.40, to lock the rear wheel hub 181 from the rear wheel shaft 163.

Referring to Figs. 44 to 49, there is shown an alternative quick-release lock mechanism 170'. It includes a cam rod 177 inserted into a through hole 167 (see Fig.

40j of an externally threaded wheel shaft 163 which has a square portion (not shown) passing through a square socket of a wheel hub 181 and which is locked on the main frame 10 by a lock nut 166'. The cam rod 177' includes a cam roller 177 by a lock screw 174 (see Figs. 41A, 42 and 43). A curved lock bar 171' is secured to the tail end of the can rod 177'. A torsion spring 175 is provided for biasing a latch bar 172 fixed on a rotable latch rod 178 to press against the curved lock bar 171', thereby causing the cam roller 173 to rotate from an unlocking position (e.g. the position shown in Fig. 43) to the locking position shown in Fig. 42.With particular reference to Fig. 47 , to prevent the relative rotation between the cam roller 173 and the cam rod 177', the enlarged portion 177" of the cam rod 177 the is externally splined, while the cam roller 173 is internally splined. When the cam roller 173 is in the locking position, the cam rod 177 is most removed form the end surface of the wheel hub 182'.

As shown in Fig. 46, the securing rods78 has a rotary member 172 at its rear end, and a stopper 179 at its front portion. 'hen operating, to prevent the cam rod 17' from being stopped by stopper 179 from inserting into the through hole 167' of the wheel shaft a163'protruding beyond the wheel hub 181', the rotary member 172 is first pressed toward the locking member 171 to outward rotate the stopper 179', and then the cam rod 177 is inserted into the through hole a67', as shown in Fig. 49.In this position, both the cam roller 173 and fixing rod 178 are spaced from the end surface of the wheel hub 181 Thereafter, the end surface of the wheel hub 181', and align the stopper 179 with the recess 168 formed on the side surface of the end portion of the wheel shaft 163 as shown in Fig. 45. Consequently, the stopper 179' is rotated into the recess 168 by the spring 175 as shown in Figs 44 and 48.In this position, both the fixing rod 178 and the cam roller 173' abut against the end surface of the wheel hub 181 to secure the wheel hub 181 to the wheel shaft 163 and complete the locking operation of the quickrelease lock mechanism 170'.

To remove the wheel hub 181 from the wheel shaft 163', the rotary member 172 is first pressed to separate the stopper 172' from the recess 168', and then the quickrelease lock mechanism 170 is pulled out.

In folding the bicycle, referring to fig. 50, the saddle member 80 carrying the seat supporting rod 75 is first removed from the leading upper tube 24 by actuating the seat lock bar 72. The sliding outer tube 52 of the rear brake assembly 50 carrying the rear lining assembly 57 is then polled upwardly and rotated through 90 degrees to the right. And, the left handlebar 131 and the right handlebar i32 are rotated to the front and folded to form a side-byside arrangement by first actuating the handlebar lock bar 141. The right pedal assembly 20C is then folded. After the right pedal assembly 200 has been complete front and rear wheel shafts 163. The handlebar assembly 130 is then rotated through 90 degrees so that the left handlebar 131 abuts against the front frame portion 90.

Secondly, referring to Fig. 5;1, the trigger screw 106 is loosened and moved to its rearmost position. The over-center hinge 98 is then pulled upwardly permitting the middle tube 95 and the rear tube 101 of upper diagonal brace 85 to be in parallel with each other. The lower diagonal brace 110 is thus bent to form a V-shape.

Finally invention inally, referring to Fig. 52, the left pedal assembly 190 and the stop support 43 are folded in turn. The front frame portion 90 is again adjusted to overlap on the rear frame portion 20. A generally triangular small unit is thus formed from the integrally mounted parts of the foldable bicycle.

Please refer to Figs. 53, to 58. A wheel connecting rod 230 is removably attached to a clip 232 mounted on the bottom of the saddle member 80. As shown in Fig.55, a cylinder stop block 231B is affixed to each end of the wheel connecting rod by a bolt 233. The end surface of the main body 231A of the wheel connecting rod 230 is formed with an eccentrical thread hole 231A aligned with an eccentrical hole 231B of the stop block 231B, permitting the bolt 233 to to through a compression spring 234 and the eccentrical hole 231B', and screw on the thread hole 231A'.

Thus, the stop block 231B always abuts against the end surface of the main body 21A via spring force Particularly, a protuberance 235 is formed on the end surface of the main body 231A and a corresponding concavity 236 is formed on the stop block 231B whereby when the stop block 2=1B is rotated to associate the protuberance 235 with the concavity 236, the stop block 231B together with the main body 231A form a cylinder body, otherwise, when the stop block 231B is rotated to detach the protuberance 235 from the concavity 23;6, an eccentrical status is formed as shown in Figs. 56 to 58. In this condition, the wheel connecting rod 230 can be affixed to the clip 232 without slipping of or fasten the wheel 180 fixedly. The wheel connecting rod 230 plays a very important roll in the final stage of folding the bicycle. As shown in Figs. 57 and 58, after the undetachable assembly is folded up into a substantially triangular small unit, the saddle member 80 can be mounted on the main frame as shown in Fig. 15, and then the lower abutment 254 of the article holder 251 can be opposed against the seat supporting rod 75, and thereafter two wheels 180s can be fitted to two ends of the main body 231A to fixedly clamp the article holder 251. Finally, the stop block 231B can be rotated, together with the main body 231A forming the eccentrical structure to rotatably affix two wheels 180 to the wheel connecting rod 230.At last, by means of inserting the tongue 79 into the groove member 78, the saddle member 80 is closely attached to the main frame 10, and the folding procedure is completed to form a unit with two wheels rotatably mounted on two sides there of as shown in Figs. 57 and 58. According to the above arrangement, this unit can be rolled on the ground within short distance.

Referring to Fig. 51, there is shown a hydrobicycle which is a second form of the present invention.

The hydro-bicycle is formed by replacing the wheels 180 of the bicycle with a propeller assembly 300.

The propeller assembly 250, as shown in Figs. 60 and 61, has a piping which includes an upper horizontal pipe 251A, a lower horizontal pipe 251B, provided with blades 272 and a rudder 272 and an extensible vertical pipe consisting of an inner pipe 257 and a slide outer pipe 260. The inner pipe 257 is formed with an outward flange F. The outer pipe 260 is formed with a drum portion 259 at its upper end to abut against a shoulder of the outward flange F for preventing the removal of the inner pipe 257 therefrom.

Rotating blades 272 are driven by a transmission which includes a square wheel shaft socket 253 mounted rotatably within the upper horizontal pipe 251A for being sleeved on the rear wheel shaft 163, a square inner drive shaft 258 mounted rotatbly within the inner pipe 257 and connected to the socket 253 by a pair of interconnecting first bevel gears 254, a square outer drive shaft 261 mounted rotatably within the outer pipe 260 and sleeved slidably on the inner drive shaft 258, and a propeller rotating shaft 269 mounted rotatably in the lower horizontal pipe 251B and connected to the outer drive shaft 261 by a pair of interconnection second bevel gears 265. In Fig. 61, bearings 1b, 2b, 3b, and 4b are respectively provided in the upper horizontal pipe 251A, the outer tube 260, and the lower horizontal pipe 251B of the piping.

Please refer to Fig. 62. A blind thread hole 31 is formed on the rear frame portion 20 adjacent to the rear wheel hub 27, and a movable fastening bolt 273 is mounted on the upper horizontal pipe 251A. The fastening bolt 273 is retained on the upper horizontal pipe 251A by a retainer mechanism, which includes a lug 273A fixedly disposed on the periphery of the upper horizontal pipe 251A, A large sleeve 273B screwed on the lug 273A for insertion of the bolt 273 there into, a stopper plate 273C screwed on the lug 273A, and two small sleeve 273C. The fastening bolt 273 is substantially L-shaped and formed with an outward flange 273E located between the lug 273 and stopper plate 273C.

According to this arrangement, the fastening bolt 273 is movably retained on the upper horizontal pipe 251A without detachment therefrom. When the fastening bolt 273 is totally screwed into the thread hole 31 of the rear frame portion 20, the front portion of the large sleeve 273B, protruding beyond the lug 273A, will engage with the enlarged portion of the thread hole 31 to prevent the fastening bolt 273 from deformation or even break due to concentrated stress. In this condition, the propeller assembly 250 can not rotate about the rear wheel hub 27.

Please now refer to Fig. 60. An upper connecting member R1 is pivoted to the upper horizontal pipe 251A, while a lower connecting member R2 is pivoted to the outer pipe -6u. The upper and lower connecting members R1, R2 are further pivoted to each other and urged to separate from each other via the compressing force of a torsion spring R3.

h cable R4 is tied to the outer pipe 260 and go through a -shaped guide member R5 disposed on the upper horizontal pipe 251A with its other end tied to a controller R5 (see Fig. 63). Particularly, the outer pipe 260 is rotatably mounted in a bushing R2'. While the bushing R2 is pivoted to the lower connecting member R2 and the cable R4 by means of two ring plates P1 and P2, and can only slide vertically.

Referring to Fig.64, the controller R5 includes a -shaped assembly body R6 is provided with an insert R8 which can be fixedly inserted into a hole 92 of the front tube 91 of the upper diagonal brace 85. The rocker arm R7 is equipped with a knob R9 for the convenience of mainly rotating the rocker arm R7 forward or rearward. When the knob R9 is moved to a rear position as shown in Fig. 63, the spring force of th torsion spring R3, the spring force of th torsion spring R3 will push the outer pipe 260 downward.

Consequently, the blades 272 of the propeller is lowered into the water for performing the propelling function. When the knob R9 is moved to a front position as indicated by phantom line in Fig. 63, the cable R4 is pulled forward to lift the blades 272 away from the water. Consequently, the rocker arm R7 is stopped by a restricting plate RO and fixed in the front position without dropping downward.

Please refer to Figs. 63 and 65. The rudder cable assembly 280 includes a pair of rudder cables 281 the front ends of which are fitted to the front wheel shaft by means of a coupler 288 having square section, with a latch 289 penetrating through the coupler 286 and the through hole of the front wheel shaft. The latch 289 is connected to the coupler 288 via a strong fine rope to avoid loss. The two rudder cables 281 are connected at their ends. A compression spring 284 is disposed on each rudder cable 281 for forcing a push rod 283 away from an adjusting bolt 285.

The push rod 283 together with the rudder cable 281 define a close portion which is surroundingly disposed on a drum member 259 located on the upper end of the outer pipe 260.

A fixing ball member 282 is disposed not the close portion to associate with a circular hole 274 of the drum member 259 ( see Fig. 80). By means of the pressure of the push rod 283 and the association of the fixing ball member 282 with the circular hole 274, the two rudder cables are constantly stretched and kept in a cross status, whereby when the left handle bar 131 and the right handlebar 132 are rotated clockwise (turn to the right), the propeller blades 272 are turned to the right rear side of the bicycle to consequently push the rear portion of the bicycle toward the left side and therefore urge the whole hydro-bicycle to turn to the right side. Reversal, when turning the handlebars to the left, the hydro-bicycle will correspondingly left turn. The above operation is identical to that of a common bicycle.

Referring to Figs. 59 and 66, the float assembly 300 includes two substantially cylindrical float members 301. Each float member 301 is provided with eight solid plastic lugs 302 which are respectively located on the front and rear portions thereof, and on which a metal ring 320A is mounted by screw. By means of screws, the metal ring 320A is further connected to a metal plate 303 which is welded to an insert pipe 304. A leg support 305 is inserted through the through hole 109 of the lower diagonal brace 110 and the longitudinal through hole 46 of the horizontal tube 25, permitting a butterfly nut 306 to be screwed on a top male thread portion 307 of the leg support 305 and fasten the leg support 305 to the main frame. As shown in Fig. 66, the leg support 305 is foldable and includes two leg pipes. At its lower portion, each leg pipe is formed with a through hole corresponding to a through hole formed on the insert pipe 304 is fitted into the leg pipe, the insert pin 308 can be inserted through the corresponding through holes of the leg pipe and the insert pipe to prevent the leg support 305 from separating from the metal ring 302A. The two float members 301 are of inflating type and can be easily inflated by a conventional mini type of inflator. After used, the float members are made flat by means of opening the valve and folded up to be stored together with the propeller assembly 250 and leg supports 305 in a canvas bag. The canvas bag, containing the propeller assembly 250 and the folded float members 301, is not large in size and can be disposed on the article holder 251 for easy carry by the bicycle.

Referring to Fig. 67, the two wheels of the bicycle can be replaced with tow foldable leg supports 305 to form an exercise bicycle. To increase the resistant force and enhance the exercise effect, a friction device 350 (see Fig. 68) is disposed on the rear wheel shaft 163. The friction device 350 includes a metal bushing 351 and a friction member 352. The bushing 351 is formed with a square hole 353 for insertion of the rear wheel shaft 163 therein to synchronize the rotation of the bushing 351 and the rear wheel shaft 163. The bushing 351 is further formed with two outward flanges 354 betweenwhich an annular clamping portion 355 of the friction member 352 is fitted to resist against the rotation of the rear wheel shaft 163 via the frictional force. An adjustment bolt 356 and butterfly nut 357 are disposed on the friction member 352 to adjust the frictional force thereof.To prevent axial displacement of the bushing 351 relative to the rear wheel shaft 163, the friction member 352 is formed with a semilunar end plate 358 riding on the horizontal member 21. When the clamping portion 355 of the friction member 352 is worn to a new one.

Referring to Fig. 70, the support rod 250 can be removed from the bicycle and a wheel support 360 can be added, permitting an additional wheel to be mounted thereon to form a tricycle. The wheel support 360 includes a substantially A -shaped member body 361, the upper end of which is eguipped with a bolt 362. Both the leg members of the member body 361 are integrally formed with a traverse tube 363 at their lower ends. A wheel shaft member 366 having an inner cylindrical portion 365, a middle outward flange 364 and an outer rectangular solid portion 366 Is rotatably fltted into the traverse tube 363 is rotatably fitted into the traverse tube 363 with its inner cylindrical portion 365 journaled in the traverse tube 363 via a bearing.The structure of the end of the outer rectangular solid portion 366 is identical to that of the rear wheel shaft 163, and a wheel can be mounted thereon via a quickrelease lock mechanism 170 or 170'. The end of the inner cylindrical portion 365 is formed with male thread suitable for engaging with a nut to secure the wheel shaft member 366 to the traverse tube 363. Particularly, the nut 367 screwed on the wheel shaft member 366 for the left wheel is welded with a rectangular solid rod 368. A fixing pin 369 is tied to the rectangular solid rod 368 to go through the nut 367 and wheel shaft member 366 and secure them together.

Furthermore, the bolt 362 of the member body 361 can be inserted through the longitudinal hole 46 of the horizontal tube 25 to be fixedly screwed on the article holder 25'. The upper portions of the two leg members of the member body 361 are connected by a reinforcing member 300h, the central portion of which is formed with a through hole for connecting the reinforcing member 300A to a rear vertical tube 26A of the main frame by means of a nut and a bolt as shown in Fig. 15.

Referring to Fig. 71, to achieve the object of driving the rear wheel, the inner end portion of the left wheel shaft member 366 is longer than that of the right wheel shaft member 366, and is grooved with a guide channel 367' on its upper surface. A square tube 368 is fitted to the inner end of the left wheel shaft member 366. The upper wall of the left end of the square tube 368' is penetrated by a pin member 369 which associates with the guide channel 367 to slidably connect the square tube 368 to the left wheel shaft member 366 without detachment.The right end of the square tube 368 is formed with a through hole 370 and an insert pin 371 is tied to the square tube 368 whereby when the bolt 362 of the wheel support 360 is inserted through the longitudinal hole 46 of the horizontal tube 25 to be screwed on the article holder 251 and secured to the main frame of the bicycle, the left and right wheel shaft members 366 are alinged with the rear wheel shaft 163.In this position, the square tube 368 can be moved to the right and fitted to both the wheel shaft member 366 and the rear wheel shaft 163 until the pin member 369 is moved to the right end of the guide channel 367', making the through hole 370 of the square tube 368 aligned with a through hole of the rear wheel shaft 163. Then, the inset pin 371 can be inserted through the through hole 370 of the square tube 368 and the through hole of the rear wheel shaft 163 to synchronize the rotation of the rear wheel shaft 163 and left wheel shaft member 366.

As explained in the foregoing, according to the present invention, the assembly for supporting the main frame 10 is capable of being changed to form a bicycle for riding on land, a hydro-bicycle for riding on smooth surfaces of water a tricycle, or an exercise bicycle for rIdIng insides. In addition to such multifunctional effect, it is advantageous in that the bicycle can be folded into a compact wheel-like unit for convenient transportation or storage.

The present invention thus explained, it is apparent that various modifications and variations can be made without departing from the scope and spirit of the present invention. It is therefore intended that the present invention be limited only as indicated in the appended claims.

Claims (26)

I.CLBIn:

1. A foldable multipurpose bicycle comprising: a foldable main frame; a handlebar assembly mounted foldably on said main frame; a seat assembly having a saddle member mounted removably on said main frame; a left pedal assembly mounted foldably on said main frame; a right pedal assembly mounted foldably on said main frame; a front wheel assembly having a front wheel of E standard diameter mounted removably on said main frame; a rear wheel assembly having a rear wheel of said standard diameter mounted removably on said main frame; a front brake assembly mounted on a front portion of said bicycle a rear brake assembly mounted on a rear portion of said bicycle; a float assembly mounted removably on said main frame; a propeller assembly mounted removably on said main frame;; two quick-release lock mechanisms for locking releasably said front wheel and said rear wheel respectively on said main frame; and a wheel connecting rod assembly mounted removably on said bicycle for attaching said front and rear wheels rotatably to center of said main frame when said bicycle is folded; whereby, when said float assembly and propeller assembly are removed from said main frame, remaining part of said bicycle form a bicycle for riding on land; when said front and rear wheels are removed from said main frame, remaining part of said bicycle can be adjusted to for a hydro-bicycle for riding on smooth surfaces of water, so that said propeller assembly can both propel saib hydrobicycle by rotating said left and right pedal assemblies and zijuct advancing direction of said hydro-bicycle is icie, said float assembly and propeller assembly can be removed from said main frame and remain parts of said bicycle can be adjusted to form a wheel-like small unit.

2. A bicycle as claimed in Claim 1, further comprising two supporting frame means which can replace said front and rear wheels to support said main frame thereby causing said bicycle to form an exercise bicycle.

3. A bicycle as claimed in Claim 2, wherein said support frame means has a damping device mounted thereon for producing a frictional resistance to rotation of a wheel shaft driven by said left and right pedal assemblies, thereby enhancing effect of exercise.

4. A bicycle as claimed in Claim 3, wherein said damping device comprises: a square sleeve receiving said rear wheel shaft, said square sleeve having two outer flanges; a friction member including an annular clamping portion fitted between said two outer flanges, and a hook portion riding on said main frame to prevent axial movement of said sleeve relative to said rear wheel shaft; an adjustment screw disposed on said friction member to adjust the binding force of said clamping portion to said sleeve.

5. A bicycle as claimed in Claim 2, wherein said support frames are tripods.

6. A bicycle as claimed in Claim 5, wherein said tripods are locked on said main frame by screw means.

7. A bicycle as claimed in Claim 1, wherein said propeller assembly is locked releasably on said main frame by a locking means when said bicycle is adjusted into said hydro-bicycle.

8. A bicycle as claimed in Claim 1, wherein said main frame comprises: a front frame portion including: an upper diagonal brace including a fronted, a first center hinge, a middle tube connected hingedly to said front tube by said first center hinge, an over-center hinge a a rear type connected hingedly to said middle tube by said over-center hinge, and an lock mechanism for interlocking releasably said middle and rear tubes, a lower diagonal brace including a front tube, a second center hinge, and a rear tube connected hingedly to said front tube of said lower diagonal brace by said second center hinge, and a rear frame portion, connected hingedly to a rear end of said upper diagonal brace, secured to a rear end of said lower diagonal brace, having a transverse through hole provided therein and allowing for insertion of said wheel connecting rod assembly therethrough.

9. A bicycle as claimed in Claim 8, wherein said lock mechanism includes a first outward flange formed at a rear end of said middle tube of said upper diagonal brace, and a second outward flange formed at a front end of said rear tube of said upper diagonal brace and alinged with said first flange, and an over-center hinge interconnecting lower ends of said flanges, one of a forward surface of said second flange and a rearward surface of said first f lange having a tapered bore therein, the other of said forward surface of said second flange and said rearward surface of said first flange having a spring-biased taper latch inserted into said tapered bore; whereby, when said lock mechanism is released to fold said bicycle, said taper latch is adjusted to disengage from said tapered bore so that said middle tube can be rotated relative to said rear tube.

10. A bicycle as claimed in Claim 1, wherein said wheel connecting rod assembly includes a connecting rod, two stopper blocks, two eccentrically movably retaining said stopper blocks to both ends of said connecting rod, and two compression springs urging said stopper blocks to abut against said connecting rod, each stopper block having an eccentric cavity, said connecting rod having corresponding rod having corresponding eccentric protuberances to separable engage with said eccentric cavities whereby when said protuberances separate from said cavities without abutting against said stopper blocks, said wheel connecting rod assembly forms a steady eccentric shaft.

11. A bicycle as claimed in Claim 10, wherein said wheel connecting rod assembly is held within said saddle member when it is idle.

12. A bicycle as claimed in Claim 1, wherein said seat assembly comprises: an upright leading upper tube fixed on said main frame and having a key strip extending lengthwise on an inner surface thereof; a supporting rod, secured to a bottom of said saddle member, movable within said leading upper tube, including an elongated keyway engaged with said key strip for preventing relative rotation between said seat supporting rod and said leading upper tube, and a plurality of equally spaced concavities provided lengthwise in said seat supporting rod; a seat lock bar, mounted rotatably on said leading upper tube, having an engagement end selectively engaged with one of said concavities, and a release end drivable to disengage said engagement end from said seat supporting rod; and, a torsion spring for biasing said engagement end of said seat lock bar to move toward said seat supporting rod so that said engagement end engages with one of said concavities to prevent relative movement between said supporting rod and said upper leading tube; whereby, height of said saddle member can be easily adjusted by engagement of said engagement end of said seat lock bar with selected one of said concavities of said seat supporting rod.

13. A bicycle as claimed in Claim 1, wherein said handlebar assembly comprises: an upright handle column; s. handlebar fitting fixed on an upper end of said handle colon; a handlebar spindle journaled on said handlebar fitting; a pair of handlebars hinged to opposite ends of said handledbar spindle; a handle lock mechanism for locking releasably said handlebar spindle and said handlebars on said handlebar fitting; whereby, when said bicycle is folded, said handle lock mechanism is released so that said handlebars can be turned forwrdly and then folded together.

14. A bicycle as claimed in Claim 12, wherein said handle lock mechanism comprises: a pair of guide rods secured to said handlebars respectively; a transverse guide slot formed horizontally in a front portion of said handlebar fitting and open at both ends of said transverse guide slot for receiving said guide rods therein; and a T-shaped hook closing removably and opening of said transverse guide slot to press over said guide rods so as to retain said guide rods in said transverse guide slot; whereby, when said T-shaped hook iS removed from said guide rods, said guide rods can be removed from said transverse guide slot so that said handlebars can be rotated to fold together.

1 A bicycle as claimed in Claim 1, wherein said front brake assembly compris a front lining disposed slidably above said front wheel and bIased to move upwardly; a front brake cable; and cam normally spaced fro said front lining and rotatable by said front brake cable to push said front lining downwardly to press against said front wheel.

16. A bicycle as claimed in Claim 1, wherein said rear ; brake assembly comprises;, an inner tube secured to said main frame and having a square adapter fixed thereon; a sliding outer tube, sleeved slidably on said inner tube, having a square socket secured to said sliding outer tube and sleeved on said square adapter of said inner tube; a rear lining assembly secured to said sliding outer tube; and means for biasing said square socket of said slide tube t engage wit said square adapter of said inner tube; whereby, when the rear brake assembly is folded, said square socket of said sliding outer tube is disengaged from said square adapter of said inner tube so that said sliding outer tube and said rear lining assembly can be rotated te a predetermined position.

17. A bicycle as claimed in claim. 1, wherein said rear brake assembly comprises: a circular plate mounted on a wheel hub of a rear eel shaft; a brake lining separately surroundlngly disposed on the periphery of said circular plate; a rotary arm connected to said brake lining; and a brake cable connecting said rotary arm to a grip, suitable for being pulled to rotate said rotary arm and press said brake lining against said circular plate to brake said rear wheel shaft.

18. A bicycle as claimed in Claim 1, wherein said left pedal assembly comprises: a left pedal; a left pedal link connected rotatably to said left pedal and adapted to connected rotatably to a main sprocket shaft; and a latch cam, removably occupying a space between said left pedal link and main sprocket shaft to interlock said left pedal link and said main sprocket shaft, and rotatable to leave the space and enable said left pedal link to 1800 rotate about said main sprocket shaft horizontally when said bicycle is folded.

19. A bicycle as claimed in Claim 1, wherein said right pedal assembly comprises: a right pedal link adapted to connected securely to a main sprocket shaft; a pedal fitting, secured to said right pedal link, including an arch upper edge at an outer end thereof and a transverse slot provided horizontally in said pedal fitting, said transverse slot being open at an outer end thereof; a right pedal; a transverse extension rod, having an end portion connected securely to said right pedal, and opposite end portion pivotably received within said transverse slot of said pedal fitting so that said transverse extension rod can 90 rotate to a vertical position; and a compression spring sleeved movably on said transverse extension rod; a sleeve, disposed slidably on said transverse extension rod of said right pedal, having an inward flange at an intermediate portion thereof, biased by said compression spring to sleeve tightly on said pedal fitting; whereby, when said sleeve is moved manually away from said pedal fitting, said transverse extension rod carrying said right pedal can 90 rotate from an operative position to a folded position to a folded position, and vice versa, and then allow said sleeve to be biased by said compression spring to sleeve on said pedal fitting.

20. A bicycle as claimed in Claim 1, wherein each of said front and rear wheel assemblies includes a hub having tow generally flat end surfaces, and a wheel shaft inserted through said hub and having an end portion with a through hole and a recess groove provided therein, and wherein each of said quick-release lock mechanisms comprises: a cam rod inserted through said through hole of said wheel shaft; a cam roller fixed on said cam rod and contacting said corresponding end surface of said hub using its greatest radius area; and stop means apt to engage with said recess groove of said wheel shaft to secure said quick-release lock rnecnafllsm to said wheel shaft.

21. A bicycle as claimed in Claim 1, wherein said front and rear wheel assembly comprise identical wheel hubs, an end surface of each said wheel hub being formed with a square hole having an extending arch slide slot, said front and rear wheel assembly further comprising identical wheel shafts, the end of each said wheel shaft being formed with two opposite L-shaped end portions defining a T-shaped groove, and wherein each said quick-release lock mechanism comprises a clamping member including: a rotary arm having one end pivoted to said end surface of said wheel hub; a sleeve body fixedly connected to the other end of said rotary arm; a clamp arm having a cylindrical portion movably received in said sleeve body; a clamp plate secured to n outer end of said clap arm, spaced from said sleeve body, and slidably received in said slide groove; and an eccentrical shaft member, going through inner ends of said sleeve body and clamp arm, suitable for being rotate to retractable extend said clamp arm within said sleeve body, whereby said clamp plate can be moved into said T-shaped groove of said wheel shaft, and then, by means of rotating said eccentrical shaft member, said clamp plate can cooperate with said sleeve body for closely clamping said Lshaped end portions of said wheel shaft to consequently secure said wheel hub to said wheel shaft.

22. A bicycle as claimed in Claim 1, wherein said propeller assembly comprises: a piping including a vertical pipe, an upper horizontal pipe secured to and communicated with said vertical pipe, and a lower horizontal pipe secured to and communicated with said vertical pipe; a rudder secured to one end of said lower horizontal tube; a propeller having a horizontal rotating shaft journaled on an end of said lower horizontal pipe, and a plurality of rotating blades fixed on said rotating shaft; a wheel shaft socket mounted rotatably within said upper horizontal pipe of said piping and adapted to be sleeved rigidly on an wheel shaft; a first pair of interconnecting bevel gears respectively fixed on said drive shaft and said wheel shaft socks for transferring rotation therbetween;; a second pair of interconnecting bevel gears respectively fixed on said drive shaft and said rotating shaft of said propeller for transferring rotation therebetween; and a pair of generally parallel rudder cables adapted to be fixed separately on a steering column at an end thereof and fixed separate on said vertical pipe of said piping at opposite end thereof, said rudder cables being interdlsposed tensely between said steering column and said vertical pipe of said piping to enable said horizontal pipes of said piping to rotate about said vertical pipe of said piping by rotating said handlebar assembly;; whereby, said handlebar assembly can drive said lower horizontal pipe of said piping and hence said rotating shaft of said propeller to rotate about said vertical pipe of said piping while said left and right pedal assemblies can drive said rotating blades of said propeller to rotate.

23. A bicycle as claimed in claim 22, wherein said vertical pipe includes an inner pipe connected to said upper horizontal pipe, an outer pipe slidably fitted to said inner pipe and connected to said lower horizontal pipe, and a drivable control mechanism for vertically moving said outer pipe, said control mechanism including an upper link member pivoted to said upper horizontal pipe, a lower link member pivoted to said upper horizontal pipe, a lower link member pivoted to said outer pipe and upper link member, a torsion spring capable of forcing upper end of said upper link member to separate from lower end of said lower link member, a cable surrounding said upper horizontal pipe and tied to said outer pipe, a controller affixed to an upper portion of said main frame for pulling said cable, said controller having a rotary arm pivoted thereto for connecting said cable to a free end of said rotary arm, said free end of said rotary arm being capable of rotating between a front position and a rear position whereby when said free end is pulled to said front position, said free end is pulled to said front position, said outer pipe is positioned in a highest position, making said propeller blades separated from the water, while when said free end is moved to said rear position, said outer pipe is positioned to a louest position due to the compression force of said torsion spring, making saic propeller blades separated from the water.

4. A bicycle as claimed in Claim 23, wherein said float assembly includes: two substantially cylindrical float members each of which is provided with two metal rings fitted respectively to front end and rear end of said float member, each said ring having an extending insert pipe; and two -shaped leg supports each having an upper end, said upper ends being respectively removably secured to front portion and rear portion of said main frame, and two leg members respectively removably fitted to said insert pipes.

25. A bicycle as claim in Claim 1, further comprising a -shaped wheel support including: a substantially -shaped member body having leg members, each said leg member having a lower end provided with a traverse tube, and an upper end removably attached to said main frame; two wheel shaft members respectively journaled in said traverse tubes, permitting said rear wheel and said additional rear wheel to be respectively mounted on outer ends thereof; and a pipe member slidably fitted to inner end of one of said wheel shaft members, capable of being moved and secured to said rear wheel shaft for sychronizing the rotation of said wheel shaft member and rear wheel shaft, whereby when stepping on said pedal assembly, said rear wheel shaft and wheel shaft member connected thereto are both rotated to drive said bicycle.

26. A foldable multipurpose bicycle constructed and adapted to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawing.