CA2290715A1

CA2290715A1 - Tricycle

Info

Publication number: CA2290715A1
Application number: CA002290715A
Authority: CA
Inventors: Masayasu Hayashi
Original assignee: K Design Co Ltd; Avantec Corp; Dox Corp
Current assignee: K Design Co Ltd; Avantec Corp; Dox Corp
Priority date: 1999-11-26
Filing date: 1999-11-26
Publication date: 2001-05-26

Abstract

A tricycle includes left and right front wheel support members which rotatably support left and right front wheels, respectively, and which are disposed on laterally opposite sides of a handle post and pivotally supported on left and right leg members which are supported by the handle post , a steering shaft which is connected to the front wheel support members to steer the front wheels in. response to the turning operation of the steering shaft:, and a driven wheel supported at a rear portion of a vehicle body frame structure. In this tricycle, a banking travel is possible, leading to an enhanced steering travelability. The handle post and the left leg member are connected to each other through a pair of left upper and lower links to form a left parallel link arrangement, while the handle post and the right leg member are connected to each other through a pair of right upper and. lower links to form a right parallel link arrangement. The left and right parallel link arrangements are formed laterally symmetrically with each other with respect to the handle post.

Description

:>PECIFICATION
TRICYCLE.
FIELD OF THE INVEnfTION
The present :invention relates to a tricycle including a pair of left and right front steerable wheels supported at a front portion of a vehic=Le body frame structure, and a single rear drivable whee=L supported at a rear portion of the vehicle body frame structure, and particularly, to an improvement in a tricycle which ca:n travE:l on a banking in an attitude in which the vehicle body frame structure is inclined in leftward and rightward directions along with the left and right front wheels .
The terms "le:ft" and "right" used in this specification mean the left and eight .in a state in which the vehicle body frame structure is turnec3 forwards in an advancing direction of the tricycle .
PRIOR ART
Tricycles which are travelable on bankings are disclosed in, for example, Japanese Patent Application Laid-open Nos.6-171569, 56-82681 and 1-229787.
In the tricyc.Les disposed in Japanese Patent Application Laid-open Nos.6-17_569 and 56-82681, the left and right front wheels are disposed to ovE:rhang largely from the turning axis .
For this reason, i.t is extremely difficult to enhance the rigidity of support of t:he front wheels, while providing a reduction in weight of each of portions or components, and if the rigidity of support is insufficient, it particularly results in lack of a stability in the banking travel. If the amount of overhanging of the left and right front wheels from the turning axis i.s large, an inertia moment of the steering system is increased, thereby making it difficult to carry out a light steering operat_Lon .
In the tricycle disclosed in Japanese Patent Application Laid-open No.l-22~~787, 'the left and right front wheels are disposed on the turning axis , but a large number of expensive ball joints are used to support the front wheels in such a disposition. This brines about a reduction in rigidity of support of each of front wheels , and makes it difficult to reduce the cost.
The present invention has been accomplished with such circumstances in view, and it is an object of the present invention to prov=Lde an inexpensive tricycle, wherein the rigidity of support: of the left and right front wheels is high to enable a banking travel, even if expensive ball joints are not used, and moreover, the steering operation can be conducted lightly.
DISCLOSURE OF THE INVENTION
To achieve the above object, according to a first aspect and feature of the; present invention, there is provided a tricycle including a pair of left and right front steerable wheels supported ait a front portion of a vehicle body frame structure, and a single rear drivable wheel supported at a rear portion of the vehicle body frame structure, wherein the tricycle comprises a cylindrical handle post which is fixedly mounted at a front end of the vehicle body frame structure and which turnably supports a steering shaft connected to a steering handlebar, left acid riglht upper links which are integrally connected to each other and pivotally supported at an upper end of the handle post, lei_t and right lower links which are integrally connected to Each other and pivotally supported at a lower end of the handlE; post , a cylindrical left leg member which is pivotally supported at upper and lower opposite ends thereof to outer ends oi_ the lef t upper and lower links , a cylindrical right :Leg member which is pivotally supported at upper and lower opposite ends thereof to outer ends of the right upper and lower links, a left front wheel support member rotatably supported on th~s left leg member, a right front wheel support member rotatably supported on the right leg member, the left front wheel being supported on the left front wheel support member and disposed immediately below the left leg member, the right front wheel being supported on the right front wheel support member and disposed immediately below the right leg member, and a steE~ring operatively-connecting means being disposed below the handle post and both the leg members for operatively connecting thE: steering shaft and the left and right front wheel suppori: members to each other.
According to a second aspect and feature of the present invention, there is provided a tricycle including a pair of left and right front ste~~rable wheels supported at a front portion of a vehicle body frame structure, and a single rear drivable wheel supported at: a rear portion of the vehicle body frame structure, wherein the tricycle comprises a cylindrical handle post which is fixedly mounted at a front end of the vehicle body frame structure and which turnably supports a steering shaft connected to a steE:ring handlebar, left and right upper links which are independE:nt from each other and pivotally supported at an upper end of the handle post , left and right lower links which are independent from each other and pivotally supported at a lower end of the handle post , a cylindrical left leg member which is pivotally supported at upper and lower opposite ends thereof to outer ends of the left upper and lower links, a cylindrical right :Leg member which is pivotally supported at upper and lower opposite ends thereof to outer ends of the right upper and lower links, a left front wheel support member turnably supported on the left leg member, a right front wheel support member turnably supported on the right leg member, left and right connecting frames which are fixedly mounted on at least ones of: the 7_eft and right upper links; and the left and right lower links , respectively, a connecting member which is turnably connected at opposite ends thereof to the connecting frames , the left front wheel being supported on the left front wheel support member and disposed immediately below the left leg member, the right front wheel being supported on the right front wheel support member and disposed immediately below the right leg member, and a steering operatively-connecting means being disposed below the handle post and both the leg members for operatively connecting the steering shaft and the left and right front wheel suppoz-t members to each other.
The steering operatively-connecting means in each of the 5 first and second features corresponds to a pit-man arm 31, a knuckle arm 32 , a tie rod 33 and a ball joint 34 in embodiments of the present invention which will be described later.
With the first and second features , the left and right cylindrical leg members are pivotally supported at upper and lower opposite ends thereof by the left and right upper and lower links , and the left and right front wheels disposed immediately below the left and right leg members are supported by the left and right front wheel support members which are rotatably supported on the left and right leg members. Therefore, the left and right froni: wheels do not overhang sideways of the left and right leg members and hence , the rigidity of support of the left and right front whE:els can be enhanced effectively in cooperation with t:he firm supporting of the upper and lower opposite ends of the leg members . As a result , it is possible to provide an enhancement: in stability of the banking travel.
In addition, because the left and right front wheels do not overhang sideways of the left and right leg members, a reduction in inertia moment of the steering system is brought about, whereby the steering operation can be conducted lightly.
Further, since the steering operatively-connecting means for operatively connecting the steering shaft and the left and right front wheel support members to each other is disposed below the handle post and. the lef t and right leg members , a wide space, which is free from interference of the steering operatively-connecaing means, can be ensured in front of and above the handle F~ost and the left and right leg members and hence, it is easy to place a carrier and the like.
Moreover, no ball joint is used in order to support the lef t and right front wheels , as described above , and hence , it is easy to ensure the rigidity of support of the front wheels , and it is possible. to provide a reduction in cost.
According to a third aspect and feature of the present invention, in addition to the first or second feature, a left upright attitude mainta=Lning means is provided between the handle post and one of the left upper and right links for exhibiting a spring force for returning the handle post to upright attitude thereof in response to the handle post inclining leftwards from 'the upright attitude, but for avoiding exhibiting a spring force, when the handle post is inclined rightwards from the upright attitude, and a right upright attitude maintaining means is provided between the handle post and one of the right upper and lower links for exhibiting a spring force for returning the handle post to upright attitude thereof in response to the handlE: post inclining rightwards from the upright attitude, but for' avoiding exhibiting a spring force, when the handle post is inclined leftwards from the upright attitude, and a spring force for biasing the handle post in a direction toward the upright attitude being applied to the left and right upright ai:titude maintaining means even in the upright state of the handle post:.
With the third feature, when the vehicle body frame structure has been inclined leftwards, a spring force for returning the vehicle body frame structure toward the upright attitude is appliecL to the vehicle body frame structure by the left upright attitude maintaining means . When the vehicle body frame structure has been inclined rightwards, a spring force for returning the vehic:Le body frame structure toward the upright attitude is applied to the vehicle body frame structure by the right upright ati:itude maintaining means . When the tricycle is at a step in a non-ridden state, a driver can ride on the tricycle witlZOUt anxiety in the upright attitude of the vehicle body frame strucaure. When the tricycle has been switched over from a turning traveling state with the vehicle body frame structure inclined, to a straight traveling state, the vehicle body frame structure is restored to the upright attitude, whereby i:he stc~erability can be further enhanced.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig . 1 is a side view of a tricycle used also as a cart , which is in a bicycle mode according to a first embodiment;
Fig.2 is a si~3e view of a tricycle used also as a cart, which is in a cart mode;
Fig.3 is an er.~large~i plan view taken in the direction of an arrow 3 in Fig. l.;

Fig.4 is an enlarged sectional view taken along a line 4-4 in Fig. l;
Fig.5 is an enlarged front view taken in the direction of an arrow 5 in fig.l with a carrier omitted;
Fig.6 is an enlarged sectional view taken along a line 6-6 in Fig.5;
Fig.7 is a fr~~nt viE:w similar to Fig.5, but with a vehicle body frame structure inclined leftwards;
Fig.8 is an enlarged sectional view taken along a line 8-8 in Fig. l;
Fig . 9 is a se<aiona:l view taken along a line 9 - 9 in Fig . 8 ;
Fig.lO is a sectional view taken along a line 10-10 in Fig.9;
Fig.ll is a side view of a tricycle used also as a cart, which is a bicycle mode, according to a second embodiment;
Fig. l2 is a front v~_ew taken in the direction of an arrow 12 in Fig.ll;
Fig. l3 is an enlarged view of an essential portion shown in Fig. l2;
Fig.l4 is an enlarged sectional view taken along a line 14-14 in Fig. l3;
Fig.l5 is a front view similar to Fig.l2, but with the vehicle body frame structure inclined leftwards;
Fig.l6 is a side vi<:w of a tricycle used also as a cart, which is in a bicycle mode, according to a third embodiment;
Fig. l7 is a side view of the tricycle used also as a cart, which is in a cari~ mode ;
Fig. l8 is a ride v_Lew of a tricycle used also as a cart, which is in a bicycle mode , according to a fourth embodiment ;
Fig. l9 is an enlarged view of an essential portion shown in Fig.l8; and Fig.20 is an enlarged perspective view of an operating lever.
BEST MODE FOR CARP:YING OUT THE INVENTION
A mode for carrying out the present invention will now be described by wavy of embodiments shown in the accompanying drawings.
Figs.l to 10 show a first embodiment of the present invention.
Referring first to Figs.l to 5, a vehicle body frame structure F1 of a tricycle that can be used also as a cart is comprised of a handle post 21, a saddle post 22, a rear frame 23, a bottom pipe :?4, a first link pipe 25 and a second link pipe 26 . The vehicle body frame structure F1 is capable of being switched over between a bicycle mode in which it has been deployed, as shown in Fig.l, and a cart mode in which it has been folded up, as shown in Fig.2.
A steering shift 27 .is turnably carried in the handle post 21 extending upward: and downwards and fitted in the handle post 21, and a steering handle bar 28 is fixedly mounted at an upper end of the steerin<~ shaft 27.
Left and right cylindrical leg members 29L and 29R are disposed on left and ricTht opposite sides of the handle post 21 to extend upwards and downwards in parallel to the handle post 21. A left front wheel supporting member 30L supporting a left front wheel WFL for .rotating movement is rotatably carried 5 on the left leg mennber 29L, and a right front wheel supporting member 30R support:ing a right front wheel WFR for rotating movement is rotatably carried on the right leg member 29R. In this case, the left front wheel WFL is disposed immediately below the left leg member 29L, and the right front wheel WFR is disposed 10 immediately below the right leg member 29R.
A pit-man arm 31 is secured to a lower end of the steering shaft 27 below a lower end of the handle post 21, and knuckle arms 32 , 32 are secured to the left and right front wheel supporting members 30L and 30R below lower ends of the left and right leg members ~;9L and 29R, respectively. Opposite ends of tie rods 33, 33 are connected to the pit-man arm 31 and the knuckle arms 32, 32 through ball joints 34, 34.
Thus, the pit-man. arm 31 is turned leftwards and rightwards through the steering shaft 27 in response to the turning of the steering handle bar 28 in left and right directions , and in ~_esponse to this , the left and right knuckle arms 32, 32 are turned leftwards and rightwards through the tie rods 33 , 33 , whereby the left front wheel WFL and the right front wheel WFR are turned leftwards and rightwards.
A mounting stay 35 is secured to an intermediate portion of the handle post 21 to protrude forwards, and a carrier 36 is attached to the mounting stay 35. It is desirable that the carrier 36 is formed so that it can be switched over between a service state in which it has protruded forwards ( a state shown by a solid line in Fig. 1 ) and in a non-service state in which it has been folded up rearwards ( a state shown by a dashed line in Fig. l).
The handle post 21 and the left leg member 29L are connected to each other through a left upper link 38L and left lower links 39L and 39L to form a left parallel link arrangement 37L, and the handlE: post 21 and the right leg member 29R are connected to each other through a right upper link 38R and right lower links 39R and :39R to i=orm a right parallel link arrangement 37R. The left and night parallel link arrangements 37L and 37R
are formed laterally symmetrically with respect to the handle post 21 .
The left and right upper links 38L and 38R are each formed integrally with ea<:h othE:r into a pipe-shape and disposed in front of the handle post 21 and the leg members 29L and 29R.
The upper links 38~ and 38R are turnably connected at their connections to the handle. post 21 through a connecting pin 40 having an axis extending longitudinally. In addition, the left and right upper links 38L and 38R are turnably connected at their outer ends to upper portions of the leg members 29L and 29R
through connecting pins 41, 41 having axes parallel to the connecting pin 40.
The left and night lower links 39L, 39R; 39L, 39R are also each formed integrally with each other into a pipe-shape and disposed at locat~_ons in which they sandwich the handle post 21 and the leg members 29L and 29R from the front and the rear.
The left and right lower links 39L, 39R; 39L, 39R are turnably connected at their connE;ctions to the handle post 21 through connecting pins 42 , 42 having axes parallel to the connecting pin 40 , and are al~;o turn.ably connected at their outer ends to lower portions of the leg members 29L and 29R through connecting pins 43 , 43 having axes parallel to the connecting pins 42 , 42 , respectively.
In the left parallel link arrangement 37L, a left upright attitude maintaining means 44L is provided between the handle post 21 and one of the left upper and lower links 38L and 39L, 39L , a . g . , the lef t lower links 39L , 3 9L . In the right parallel link arrangement 37R, a right upright attitude maintaining means 44R is provided between the handle post 21 and one of the right upper and lower links 38~z and 39R, 39R, e.g., the right lower links 39R, 39R.
Referring to l.~'ig. 6 , the left upright attitude maintaining means 44L includes a support shaft 46 mounted between bracket plates 45, 45 secured respectively to the left lower links 39L
and 39L and having an axis parallel to the connecting pins 40 to 43 of the left parallel link arrangement 37L, a guide rod 47 extending upwards and downwards and turnably carried at its lower end on the support shaft 46 , a movable tube 48 coaxially surrounding the guide rod 47 , a stationary retainer 49 disposed between the left .Lower .links 39L, 39L and secured to a lower portion of the guide rod 47, a movable retainer 50 secured to the movable tube 48 , a coal spring 51 mounted under compression between the stationary retainer 49 and the movable retainer 50 to surround the guide rod 47, and an abutment plate 52 fixed to the handle post 2;1, so that it can be put into abutment against an upper end of the movable tube 48.
A support tube 53 is secured to the handle post 21 in an intermediate portion between the upper and lower links 38L and 39L, 39L of the left parallel link arrangement 37L and extends toward the left leg member 29L, and the abutment plate 52 is secured to a tip end of the support tube 53. The abutment plate 52 is provided with a guide bore 54 through which the guide rod 47 is movably inserted, with an upper end of the guide rod 47 being passed through the abutment plate 52 to protrude upwards .
An inward-fa~~ing collar 55 protruding radially inwards is secured to an inner surface of a lower end of the movable tube 48 to surround the guide rod 47. A limiting collar 56 protruding radially outwards is secured to the guide rod 47 with its outer periphery brought into sliding contact with the inner surface of the movable tube 48, so that it can be put into abutment against an upper surface of the inward-facing collar 55. Moreover, a limiting collar 56 is secured to the guide rod 47 in such a manner that the inward-facing collar 55 of the movable tube 48 biased upwards by the coil spring 51 is put against the limiting collar 56 in a state in which the handle post 21 assumes an upright attitude. In this case, the axial length of the movable tube 48 as well as the position of securing of the inward-facing collar 55 to the movable tube 48 are determined, so that the upper end of the movable tube 48 is in abutment against the lower surface of the abutment plate 52 , or is at a location extremely close to the lower surface of the abutment plate 52.
A nut 57 is t:hreadE:dly fitted over the lower portion of the guide rod 47, so that its advanced and retreated positions can be regulated. An enc~ of downward movement of the movable tube 48 is defined by abutment of the inward-facing collar 55 against the nut 57.
The leg members 29I, and 29R are also inclined leftwards in response to the leftward inclination of the handle post 21, as shown in Fig.7, because the left and right parallel link arrangements 37L and 37R are formed between the handle post 21 and the left and right leg members 29L and 29R. In this case, in the left upright attitude maintaining means 44L, the movable tube 48 is pushed downwards by the abutment plate 52, while compressing the coil spring 51, and a spring force of returning the handle post 21 to it:~ upright attitude is applied to the abutment plate 52 , i . a . , to the handle post 21. On the other hand, when the handle post 21 is tilted rightwards from the upright attitude, a.n upper limit position of the movable tube 48 is defined by abut=ment of the inward-facing collar 55 against the limiting collar 56. Therefore, the abutment plate 52 is moved away from the upper end of the movable tube 48 and inclined rightwards and hence, a spring force cannot be applied from the left upright attitude maintaining means 44L to the handle post 21.
5 The right upright attitude maintaining means 44R
basically has the ;same structure as the left upright attitude maintaining means 44L, anal the detailed description thereof is omitted. The right upright attitude maintaining means 44R
exhibits a spring force for returning the handle post 21 to the 10 upright attitude in response to the rightward tilting movement of the handle post 21 from the upright attitude, but when the handle post 21 is tilted leftwards from the upright attitude, the spring force ~:annot be applied from the right upright attitude maintaining means 44R to the handle post 21.

15 Referring also to Figs . 8 and 9 , the rear frame 23 comprises a pair of frame plates 60, 60 parallel to each other, a tube 61 which has an ax=Ls parallel to rotational axes of the left and right front wheels WF~, and WFR and which has opposite outer ends protruding outwards from the frame plates 60, 60 and connects the frame plates 60, 60 to each other, and a pair of left and right pipe-shaped rear forks 62, 62 secured to the frame plates 60, 60 and the tube 61. When the vehicle body frame structure F1 is in t:he bicycle mode , as shown in Fig . 1, the rear forks 62, 62 are inc:Lined rearwards and downwards from the frame plates 60 , 60 and the tube; 61 to extend rearwards , and the rear wheel WR, which is a driven wheel, is pivotally supported at rear ends of the rear forks 62, 62.
A crankshaft 64 is rotatably carried in the tube 61 through a ball bearing 63 , and crank pedals 65 , 65 are fixed to opposite ends of the cranks:haf t 6 ~4 . Moreover , a driving sprocket 66 is fixed to the crankshaft 64 on the right of the tube 61, and an endless chain 68 i;s reevE:d around a follower sprocket 67 fixed to the rear whee:L WR and around the driving sprocket 66.
Therefore, the rear wheE:l WR is rotated by the depression of the crank pedals Ei 5 , 6 5 ,.
The saddle post 22 extends upwards from the rear frame 23 and is turnably connected at its lower end to the rear frame 23 through a pivot ( a bolt in this embodiment ) 69 which is mounted between both the frame p_Lates 60 , 60 and has an axis parallel to the crankshaft 64. A saddle 70 is mounted at an upper end of the saddle post 22.
The bottom pi~~e 24 connects the lower portion of the handle post 21 and the reeir frame 23 to each other. The bottom pipe 24 is turnably connected ~at its one end to a bracket 71 mounted at the lower portion of t:he handle post 21 through a pivot 72 having an axis parallel to the pivot 69, and is turnably connected at the other end to the rear frame 23 through a pivot (a bolt in this embodiment) 73 which is mounted between both the frame plates 6C~, 60 and has an axis parallel to the pivot 72.
The first link pipe 25 connects an intermediate portion in the upward and downward direction of the saddle post 22 and a lengthwise intermediate portion of the bottom pipe 24 to each other. The first link pipe 25 is connected at its one end to a bracket 74 secured the intermediate portion in the upward and downward direction of the saddle post 22 through a pivot ( a bolt in this embodiment) 75 having an axis parallel to the pivots 69, 72 and 73, and is connected at the other end to a bracket 76 secured to the lE:ngthw=Lse intermediate portion of the bottom pipe 24 through a pivot (a bolt in this embodiment) 77 having an axis parallel to the pivot 75.
The second link pipe 26 connects an intermediate portion in the upward and downward direction of the handle post 21 and a lengthwise intermediatE: portion of the first link pipe 25 to each other. The second link pipe 26 is connected at its one end to a bracket 78 secured to the intermediate portion in the upward and downward direcaion of the handle post 21 through a pivot 79 having an axis parallel to the pivots 69 , 72 , 73 , 75 and 77 , and is connected at the other end to a bracket 80 secured to the lengthwise intermediate portion of the first link pipe through a pivot ( a bolt in this embodiment ) 81 having an axis 20 parallel to the pivot 79.
The handle post 21,. the saddle post 22, the rear frame 23, the bottom pipe 24, the first link pipe 25 and the second link pipe 26 , whic:h are turnably connected to one another through the pivots 69, 72, 73, 75, 77, 79 and 81 and form the 25 vehicle body frame structure F1 in the above manner, comprise a link mechanism which is capable of switching over, from one to another, a bicycle mode in which the vehicle body frame structure F1 has been deployed, so that both the left and right front wheels WFL aIld WFR .and the rear wheel WR are grounded to provide a maximum wheel base , as shown in Fig . 1, and a cart mode in which the vehicle body frame structure F1 has been folded up, so that the rear wheel WR spaced apart from the ground surface is inserted between the left and right front wheels WFL and WFa which are in their grounded states, as shown in Fig.2.
To facilitatE: the operation of switching over the bicycle mode and the cart mode from one to the other, a grip 82 is provided at the upper end o:E the waddle post 22 to protrude rearwards of the saddle 70.
When the veh_LCle body frame structure F1 is in the cart mode, the cart mode can be maintained, if the steering shaft 27 and the saddle post 22 are fastened by a fastening means 83 such as a rubber band and. a string member, as shown by a dashed line in Fig.2. When the vehicle body frame structure F1 is in the bicycle mode, i:he bicycle mode of the vehicle body frame structure F1 can bE; maini~ained by a lock means 84.
The lock means 84 is provided between the saddle post 22 and the rear frame ~:3 amon.g the handle post 21, the saddle post 22 , the rear frame :~3 , thc: bottom pipe 24 , the first link pipe and the second link pipe 26 which form the vehicle body frame structure F1.
25 The lock means 84 includes a resilient member 85 which is made of an elastic material such as a rubber and which is fixed to the rear frame 23 and sandwiched between the saddle post 22 and the rE:ar frame 23 in such a manner to exhibit a resilient force opposing a riding load applied from the saddle post 22 when the vehicle body frame structure F1 is in the bicycle mode , and an engage member 86 which is mounted to the rear frame 23 to releasably engage the saddle post 22 to maintain the relative positions of the; saddle post 22 and the rear frame 23.
Referring also to I?ig.l0, a support plate 87 is secured between both the frame plates 60, 60 in the rear frame 23 to oppose the rear surface of the saddle post 22 , when the vehicle body frame structure F1 has been brought into the bicycle mode .
The resilient membE:r 85 is secured to the support plate 87 , so that its abutment :~urfacE: 85a recessed in an arcuate shape in correspondence to the rear surface of the pipe-shaped saddle post 22 faces toward the saddle post 22. Thus, when the vehicle body frame structure F1 hays been brought into the bicycle mode, the resilient member 85 is'. sandwiched between the support plate 87 secured to the rear frame 23 and the saddle post 22 and exhibits the resilient force opposing the riding load applied from the saddle post 22. Moreover, the resilient force exhibited by the resilient member 85 is applied to the saddle post 22 in a direction to turn the saddle post 22 forwards about the axis of the pivot 69 and also applied to the rear frame 23 in a direction to turn tree rear frame 23 rearwards about the axis of the pivot '73. The resilient force exhibited by the resilient member 8~~ is applied to the saddle post 22 and the rear frame 23 to provide the cart mode.
The engage member 86 is turnably support at its base portion by a shaft 88 which is provided to extend between both the frame plates 60 , 60 and has an axis parallel to the crankshaft 5 64. The engage member 86 has a hook-shaped engage claw 86a provided at its ti.p end. On the other hand, a substantially U-shaped locking maember 91 is secured to the saddle post 22, so that the engage claw 86a can be brought into engagement with the locking member 91. V~hen the vehicle body frame structure 10 F1 is in the bicyclE: mode, the relative positions of the saddle post 22 and the rear frame 23 are maintained by bringing the engage claw 86a into engagement with the locking member 91, while compressing the resilient member 85.
A torsion spring 89 is mounted between the engage member 15 86 and a receiving plate 90 secured to an inner surface of one of the frame plate: 60 , 60 to surround the shaft 88 , so that the engage member 86 is biased and turned by a spring force of the torsion spring 89 in a direction to bring the engage claw 86a into engagement with the locking member 91.

20 Further, an operating portion 86b is integrally provided at the base portion of the engage member 86 to protrude outwards in a radial direction of the shaft 86 . Thus , the engage member 86 can be operated _Ln a direction to disengage the engage claw 86a from the locking membe=r 91 by putting an operator' s finger onto the operating portion 86b to operate the latter.
The operation of the first embodiment will be described below. If the vehicle body frame structure F1 is deployed into the bicycle mode , as shoran in Fig . 1, the tricycle used also as a cart can be used as a bicycle . In this case , when the vehicle body frame structure F1 has been deployed into the bicycle mode, the locking means fs4 is provided between the saddle post 22 and the rear frame 23 among the handle post 21, the saddle post 22 , the rear frame 23 , the bottom pipe 24 , the first lynk pipe 25 and the second link pipe 26 which form the vehicle body frame structure F1, and the relative positions of the saddle post 22 and the rear frame 23 arE: maintained by the locking means 84 , whereby the bicycle mode of the vehicle body frame structure F1 is maintained.
Moreover, the locking means 84 includes the resilient member 85 which is sandwiched between the saddle post 22 and the rear frame 23 arid exhibits the resilient force opposing the riding load. Even if the fabricating accuracy and assembling accuracy for the h~indle post 21, the saddle post 22 , the rear frame 23, the bottom pipe 24, the first link pipe 25 and the second link pipe 26 are somewhat poor, it is possible to absorb the fabricating and assembling errors of the handle post 21, the saddle post 22 , the rear frame 23 , the bottom pipe 24 , the first link pipe 25 and the; second link pipe 26 by the resilient member 85 to prevent the looseness from occurring among the handle post 21, the waddle post 22 , the rear frame 23 , the bottom pipe 24, the first link pipe 25 and the second link pipe 26, thereby enhancing the riding comfort. In addition, it is possible to enhance the. cushion property by exhibiting the resilient force opposing the riding load by the resilient member 85, thereby furthE:r enhancing the riding comport.
The left and right parallel link arrangements 37L and 37R
are formed between the handle post 21 and the left and right leg members 29L anti 29R a.nd hence, the leg members 29L and 29R
are inclined leftwards and rightwards in response to the leftward and rightward inclination of the handle post 21, whereby the left an~i right front wheels WFL and WFR can be inclined.
Thus , a banking travel of the tricycle is feasible , i . a . , the tricycle can be al~Lowed t:o travel with the vehicle body frame structure F1 inclined leftwards or rightwards, leading to an enhanced steering travelability.
Moreover, thc~ left and right upper links 38L and 38R in the parallel link arrangernents 37L and 37R are formed integrally with each other, and the left and right lower links 39L, 39L
and 39R, 39R in the parallel link arrangements 37L and 37R are also formed integrally with each other. Therefore, it is possible to reduce the number of parts forming the left and right parallel link arran.gement:s 37L and 37R as much as possible and to reduce the number of assembling steps.
Further, in the left parallel link arrangement 37L, the left upright attitude maintaining means 44L is provided between the handle post 21 and the left lower links 39L and 39L for exhibiting the spring force for returning the handle post 21 to the upright attitude in response to the leftward inclination of the handle post .>.1 from the upright attitude, but for avoiding exhibiting a spring force, when the handle post 21 is inclined rightwards from the upright attitude. In the right parallel link arrangement ?.7R, the right upright attitude maintaining means 44R is provided between the handle post 21 and the right lower links 39R anal 39R for exhibiting the spring force for returning the handle post 21 to the upright attitude in response to the rightward inclination of the handle post 21 from the upright attitude, but fo~_~ avoiding exhibiting a spring force, when the handle post 21 i,s inclined leftwards from the upright attitude. Therefore, whE:n the vehicle body frame structure F1 has been inclined either leftwards or rightwards, the spring force for returninct the handle post 21 to the upright attitude is applied to the vehicle body frame structure F1. Thus , when the tricycle is at stop in a non-ridden state, the vehicle body frame structure F1 can bE: brought into the upright attitude, whereby a driver car. ride on the tricycle without anxiety. When the tricycle is switched over from the turning traveling state with the vehicle body frame structure F1 inclined to a straight traveling state, the vehicle body frame structure F1 is restored to the upright attitude, whereby the steerability can be further enhanced.
Particularly, the left and right cylindrical leg members 29L and 29R are pivotally supported at their upper and lower ends by the left and x~igh.t upper and lower links 38L, 38R and 39L, 39R, and the left and right front wheels WFL and WFR disposed immediately below the left and right leg members 29L and 29R
are supported by the left: and right front wheel support members 30L and 30R rotatably carried on the left and right leg members 29L and 29R. Therefore, the left and right front wheels WFL and WFR do not overhang sideways of the leg members 29L and 29R, and hence, the support rigidity of the left and right front wheels WFL and WFR is enhanced effectively in cooperation with the firm supporting of the upper and lower opposite ends of the leg members 29L and 29R and as a result, the stability of the banking travel can be enhanced.
In addition, since: the left and right front wheels WFL
and WFR do not overhang sideways of the leg members 29L and 29R, a reduction in inertia moment of the steering system is provided, whereby the steering car. be carried out lightly.
Further, the steering operatively-connecting means for operatively connecting t:he steering shaft 27 and the left and right front wheel support members 30L and 30R to each other, i.e., the pit-man ,arm 31, the knuckle arm 32, the tie rod 33 and the ball joint 34 are disposed below the handle post 21 and the left and right leg members 29L and 29R. Therefore, wide spaces, which are free from the interference of the steering operatively-connecting means , can be ensured in front and above the handle post 21 and the left and right leg members 29L and 29R, whereby it is easy to place the carrier 36 and the like.
Moreover, the: ball joint is not used in order to support the left and right front wheels WFL and WFR, as described above, and hence, it is ea:~y to ensure the support rigidity of the front wheels WFL and WFR and to provide a reduction in cost.
When the tricycle used also as the cart is used as a two-wheel cart, the relative position locking state of the 5 saddle post 22 and the rear frame 23 by the locking means 84 may be released in the state in which the vehicle body frame structure F1 is in the bicycle mode, and the grip 82 may be grasped to fold up the vehicle body frame structure F1.
In this case, the resilient member 85 of the locking means 10 84 exhibits the spring force for biasing the saddle post 22 and the rear frame 23 _Ln the direction to provide the cart mode, as described above and her,~ce, when the engage member 86 has been turned by the operating portion 86b to release the maintaining of the relative positions of the saddle post 22 and the rear 15 frame 23 , the saddle post; 22 and the rear frame 23 are biased in the direction to provide the cart mode by the resilient force of the resilient mernber 85 , thereby facilitating the operation for switching over the tricycle from the bicycle mode to the cart mode.
20 In the sate in which the vehicle body frame F1 has been folded up into the cart mode, the rear wheel WR is spaced apart from the ground surf: ace anal inserted between the left and right front wheels WFL and WFR which are in the grounded states and hence, the tricycle: used also as the cart can be used as the 25 two-wheel cart. In this case, the rear wheel WR spaced apart from the ground surface cannot be driven from the ground surface with the movement of cart, and hence, the crank pedals 65, 65 cannot be rotated. Therefore, the cart can be moved freely ion the forward and rE;arward directions without being obstructed by the crank pedals 65, 65.
Figs.ll to .L5 show a second embodiment of the present invention.
Referring first to~ Figs . 11 and 12 , a handle post 21 and a left leg member 29L are connected to each other through a pipe-shaped left Upper 7_ink 95L and a pipe-shaped left lower link 96L to form a left parallel link arrangement 94L, and the handle post 21 and a right leg member 29R are connected to each other through a pipe-shaped right upper link 95R and a pipe-shaped right :Lower .Link 96R to form a right parallel link arrangement 94R. The left and right parallel link arrangements 94L and 94R are formed laterally symmetrically with respect to the handle post 21.
A pair of upper support plates 97 are secured to an upper portion of the handle post 21 and extend laterally with the handle post 21 sanclwiche~i therebetween from the front and the rear, and a pair oj= lowe:r support plates 98 are secured to a lower portion of the handlle post 21 and extend laterally with the handle post 21 sandwiched therebetween from the front and the rear. Upper brackets 99L and 99R are secured to the left and right leg members 29L and 29R in correspondence to the upper support plates 97, and lower brackets 100L and 1008 are also secured to the le:Et and. right leg members 29L and 29R in correspondence to the lower support plates 98.
The left an~i right: upper links 95L and 95R are turnably connected at their inner ends to opposite ends of the upper support plates 97 through connecting pins 101, 101 having axes extending on the :Longitudinal direction of the vehicle body frame structure F1, respectively, and at their outer ends to the upper brackets 99L and 99R through connecting pins 102 , 102 having axes parallel to the connecting pins 101, respectively.
The left and right lower links 96L and 96R are turnably connected at their inner ends to opposite ends of the lower support plates 98 through connecting pins 103 , 103 having axes parallel to the connecting pins 101, 102 , respectively, and at their outer ends to the lower brackets 100L and 1008 through connecting pins 104 , 104 having axes parallel to the connecting pins 103, respectively.
In such parallel link arrangements 94L and 94R, the left and right upper linka 95L and 95R are independent from each other, and the left and right lower links 96L and 96R are independent from each other. Therefore, in this structure as it is, the parallel link arrangements 94L and 94R permit the upward and downward movement of the handle post 21 relative to the leg members 29L and 29R.
Therefore, th.e left and right lower links 96L and 96R are provided with connE:cting frames 105L and 1058, respectively, and the connecting ,members 106 , 106 are turnably connected at their opposite ends to the connecting frames 105L and 1058, respectively.
Referring a~_so to Figs . 13 and 14 , the connecting frame 105L provided on the lE:ft lower link 96L is formed into a substantially triangular shape by a rising pipe 107L integrally connected to the inner end of the left lower link 96L and extending upwards, and a connecting pipe 108L connecting an intermediate portion of the left lower link 96L and an upper portion of the ris_Lng pipe 107L to each other. The connecting frame 1058 provided on the right lower link 96R is formed into a substantially i~riangular shape by a rising pipe 1078 integrally connected to 'the inner end of the right lower link 96R and extending upwards" and a connecting pipe 1088 connecting an intermediate portion of the right lower link 96R and an upper portion of the rising pipe 1078 to each other.
The connecting members 106, 106 are each formed of a band-shaped flat p:Late, and are disposed at a location where they sandwich the handle post 21 from the front and the rear.
The connecting members 106 , 106 are turnably connected at their opposite ends to upper portions of the rising pipes 107L and 1078 of the connecting frames 105L and 1058 through connecting shafts 109, 109, respectively.
Such a simple structure in which the connecting members 106 , 106 are merely turnably connected at their opposite ends to the connecting i=rame 105L provided on the left lower link 96L and to the connecting i_rame 1058 provided on the right lower link 96R, ensures tlhat the handle post 21 cannot be permitted by the parallel link arrangements 94L and 94R to be moved upwards and downwards relative to the leg members 29L and 29R, and can withstand a load applied thereto, whereby the function of the left and right parallel link arrangements 94L and 94R can be maintained.
More specifically, as shown in Fig. l5, the leg members 29L and 29R are inclined leftwards or rightwards with the leftward or rightward inclination of the handle post 21, whereby the vehicle body :Frame structure F1 can be inclined either leftwards or righi~wards to enable a banking travel of the tricycle, leading to an enhanced steering travelability.
In the left p~~rallel link arrangement 94L, a left upright attitude maintaining means 110L is provided between the handle post 21 and one of the left upper and lower links 95L and 96L, a . g . , the lef t lower link 9 6L . In the right parallel link arrangement 94R, a right upright attitude maintaining means 1108 is provided between the handle post 21 and one of the right upper and lower links 952 and 96R, e.g. , the right lower link 96R.
The left upright attitude maintaining means 110L includes a guide tube 111 wh~_ch is secured to the handle post 21 and has an axis extending in a lateral direction and which is closed at its opposite ends by end wall members 112L and 1128, respectively, a guide rod 113 which is secured at their opposite ends to the end wall members 112L and 1128 and concentrically disposed within the guide tube 111, a movable tube 114L which is accommodated witlhin the guide tube 111 for sliding movement along the guide rod 113, a spring 115 for exhibiting a spring force in a direction to move the movable tube 114L toward the end wall member 112L , an abutment arm 117L provided on the movable tube 114L to protrude downwards from a slit 116L provided in 5 a left lower sidewall of the guide tube 111, and a roller 119L
which is rotatabl~~ carried at an upper end of the connecting frame 105L through a support shaft 118L having an axis parallel to the connecting pins 101 to 104 and which is capable of being put into abutment against the abutment arm 117L from the outside 10 in an axial direct: ion of. the guide tube 111.
The right ~ipright attitude maintaining means 1108 includes the guide tube :111, the guide rod 113 and the spring 115 commonly included in the left upright attitude maintaining means 110L, and further includes a movable tube 1148 15 accommodated within the guide tube 111 for sliding movement along the guide rod 113, an abutment arm 1178 provided on the movable tube 1148 to protrude downwards from a slit 1168 provided in a right lower s~_dewall of the guide tube 111, and a roller 1198 which is rotata.bly ca:cried at an upper end of the connecting 20 frame 1058 through a support shaft 1188 having an axis parallel to the support shaft 118L .and which is capable of being put into abutment against the abutment arm 1178 from the outside in the axial direction of the guide tube 111.
Collars 120L and 1208 are secured to the movable tubes 25 114L and 1148 with i~heir outer peripheries in sliding contact with an inner surface of the guide tube 111, and the spring 115 , which is a coil spring, is mounted under compression between both the collars 1.20L and 1208 to surround the guide rod 113.
When the vehicle body frame structure F1 has been inclined leftwards, as shoran in Fig.l5, the abutment arm 117L and the movable tube 114L in the left upright attitude maintaining means 110L are pushed rightwards by the roller 119L, while compressing the spring 115. During this time, in the right upright attitude maintaining means 1108, the movable tube 1148 is in abutment against the end wal_1 member 112L, and the roller 1198 is spaced apart from the abutment arm 1178. Therefore, the spring force for returning the handlE; post 21 to the upright attitude is applied from the lE:ft upright attitude maintaining means 110L
to the handle post .21 through the guide tube 111, and the right upright attitude ma.intair.~ing means 1108 cannot exert the spring force to the handle post 21 . On the other hand, when the handle post 21 has been inclined rightwards from the upright attitude, the spring force foo returning the handle post 21 to the upright attitude is applied from the right upright attitude maintaining means 1108 to the handle post 21 through the guide tube 111, and the left upright attitude maintaining means 110L cannot exert the spring force to the handle post 21.
Even in the second Embodiment, an effect similar to that in the first embodiment can be provided.
Figs. l6 and .L7 show a third embodiment of the present invention.
A vehicle body framE~ structure F2 in a tricycle used also as a cart is comprised of a handle post 21 (see the first and second embodiment~~ ; and 'which is not shown in Figs . 16 and 17 ) , a saddle post 22 , ~i rear frame 121, a bottom pipe 24 and a link pipe 122. The vehicle body frame structure; F2 is capable of being switched over betwE:en a bicycle mode in which it has been deployed, as shown in Fig.l6, and a cart mode in which it has been folded up, a~; shown in Fig. l7.
The rear frame 121 is comprised of the following members connected integral:Ly with one another: a tube 61 which rotatably supports crank ped<ils 65, 65, a first pipe frame 123 extending in a forward lower inclined manner from the tube 61 in the bicycle mode, a second piF>e frame 124 extending in a forward upper inclined manner from the tube 61 in the bicycle mode, a rear fork 62 which extends in a rearward lower inclined manner from the tube 61 in the bicyc.Le mode and on a rear end of which a rear wheel WR is supported by a shaft , and a reinforcing pipe 125 which connects an upper end of the second pipe frame 124 and an intermediate: portion of the rear fork 62 to each other.
The bottom pipe 24 is turnably connected at its one end to a bracket 71 mounted at a lower portion of the handle post 21 through a pivot 72 having an axis parallel to a rotational axis of the rear wheel WR, and a lower end of the saddle post 22, the other end of the bottom pipe 24 and a tip end of the first pipe frame 124 in the rear frame 121 are connected together through a pivot l2fi para:Llel to the pivot 72.
The link pipe 122 connects an intermediate portion in the upward and downward direction of the handle post 21 and a lengthwise intermE:diate portion of the saddle post 22 to each other. The link pipe 122 is connected at its one end to a bracket 127 secured to the intermediate portion in the upward and downward direction of the handle post 21 through a pivot 128 having an axis parallel to the pivots 73 and 126, and at the other end to a bracket 129 secured to the lengthwise intermediate portion of ithe saddle post 22 through a pivot 130 having an axis parallel to the pivot 128.
The handle post 21, the saddle post 22, the rear frame 121, the bottom pipe 24 and the link pipe 122 , which are turnably connected to one another through the pivots 72, 126, 128 and 130 to form the vehicle body frame structure F2, comprise a link mechanism which is capable of switching over, from one to another, the bicycle mode in which the vehicle frame body structure FZ has been deployed, so that both of left and right front wheels WFL and. WFR and the rear wheel WR have been grounded to provide the maximum wheel base , as shown in Fig . 16 , and the cart mode in which i:he vehicle frame body structure F2 has been folded up, so that the rear wheel WR spaced apart from the ground surface has been inserted between the left and right front wheels WFL and WFR which are in their grounded states , as shown in Fig. l7.
When the vehicle frame body structure Fz is in the bicycle mode, the bicycle mode of the vehicle frame body structure FZ
can be maintained by loclking means 131 and 132.

The locking means 131 is provided between the saddle post 22 and the rear frame 121 among the handle post 21, the saddle post 22, the rear frame 121, the bottom pipe 24 and the link pipe 122 which form the vehicle body frame structure F2.
The locking means 131 includes a resilient member 133 which is made of a~z elasi~ic material , a . g . , a rubber and which is fixed to the rear frame 121 in such a manner that it is sandwiched between the saddle post 22 and the rear frame 121, when the vehicle body frame structure FZ is in the bicycle mode, and an engage membE;r 135 which is mounted to the rear frame 121 to maintain the re:lativE: positions of the saddle post 22 and the rear frame 121 so as to releasably engage a locking member 134 mounted on thE: saddle post 22.
The resilient member 133 is secured to upper ends of the second pipe frame ;portion 124 and the reinforcing pipe 125 in the rear frame 121, and is sandwiched between the saddle post 22 and the rear frame 121 to exhibit a resilient force opposing a riding load applied from the saddle post 22 , when the vehicle body frame structure FZ is in the bicycle mode.
The locking means 132 is provided between the bottom pipe 24 and the saddle post 22 among the handle post 21, the saddle post 22, the rear :Frame 121, the bottom pipe 24 and the link pipe 122 which form the vehicle body frame structure F2.
The locking means 132 includes a resilient member 136 which is made of an elastic material , a . g . , a rubber and which is fixed to the bottom pipe 24 in such a manner that it is sandwiched between the bottom frame 24 and the saddle post 22 , when the vehicle body frame structure Fz is in the bicycle mode, and an engage member 138 which is mounted to the saddle post 22 to maintain the relative positions of the saddle post 22 and 5 the bottom pipe 24 so as to releasably engage the bottom pipe 24. A support arm 137 is integrally connected to the bottom pipe 24 in such a manner that a tip end thereof is opposed to a front surface of the saddle post 22 in the bicycle mode, and the resilient membE:r 136 is fixed to the tip end of the support 10 arm 137 in such a manner that it engages the front surface of the saddle post 22 . Thus , when the vehicle body frame structure FZ is in the bicycle mode, the resilient member 136 is sandwiched between the support arm 7L37 and the saddle post 22 to exhibit the resilient force opposing the riding load.
15 The engage mE;mber 7.38 is mounted to the saddle post 22, so that it engages 'the tip end of the support arm 137 , when the vehicle body frame structure F2 is in the bicycle mode.
In the first and second embodiments , the handle post 21, the saddle post 22 , the rear frame 23 , the bottom pipe 24 , the 20 first link pipe 25 and t:he second link pipe 26 are turnably connected together through the seven pivots 69, 72, 73, 75, 77, 79 and 81 to form t:he vehicle body frame structure F1, and on the other hand, in the third embodiment, the handle post 21, the saddle post 22 , the rE:ar frame 121, the bottom pipe 24 and 25 the link pipe 122 are turnably connected together through the four pivots 72, 126, 128 and 130 to form the vehicle body frame structure F2, whereby thE: arrangement of the vehicle body frame structure FZ can t>e simplified.
Figs. l8 to :?0 show a fourth embodiment of the present invention.
The attitude; of a vehicle body frame structure FZ when in a bicycle mode i=o maintained by first and second locking means 141 and 142. The ~=first .Locking means 141 is provided between a saddle post 22 and a rear frame 121 of the components of a vehicle body frame structure F2, and the second locking means 142 is provided between a bottom pipe 24 and the saddle post 22.
The first lo<:king nneans 141 includes a resilient member 133 which is made ~~f an elastic material, e.g., a rubber and which is fixed to i~he rear frame 121 in such a manner that it is sandwiched between the saddle post 22 and the rear frame 121, when the vehicle body frame structure FZ is in the bicycle mode, a lever 143 turnabl.y mounted to the saddle post 22, a hook 145 which is secured to the rear frame 121 to maintain the relative positions of the saddle post 22 and the rear frame 121 so as to releasably engac3e a locking pin 144 mounted at one end of the lever 143, and a torsion spring 146 mounted between the lever 143 and the saddle post 22 to exhibit a spring force for biasing the lever 143 in a direction to bring the locking pin 144 of the lever 143 into engagement with the hook 145.
The resilient member 133 is secured to the upper ends of the second pipe frame 124 and the reinforcing pipe 125 in the rear frame 121, and is :sandwiched between the saddle post 22 and the rear framE; 121 t:o exhibit a resilient force opposing a riding load applied from the saddle post 22 when the vehicle body frame structure FZ is in the bicycle mode.
The second locking means 142 includes a resilient member 136 fixed to a tip e;nd of a support arm 137 integrally connected to the bottom pipe: 24, and an operating lever 148 turnably mounted to the saddle post 22 , so that it can be brought into engagement with a l~~cking pin 147 fixedly mounted on the support arm 137. When the vehicle body frame structure Fz is in the bicycle mode, the :resilient member 136 is sandwiched between the bottom frame ~!4 and the saddle post 22 by bringing the operating lever 1413 into engagement with the locking pin 147 , whereby the relative positions of the saddle post 22 and the bottom pipe 24 are maintained.
The operating lever 148 is integrally provided with the following portions as shown in Fig.20: a flat plate portion 148a having a support bone 150 which is provided therein and through which a support shaft 149 for turnably mounting the operating lever 148 to the saddle post 22 is inserted, an engage portion 148b which protrudes from an outer edge of the flat plate portion 148a toward the support arm 137 , so that it can be brought into engagement with the locking pin 147, a first operating portion 148c which protrudes from the outer edge of the flat plate portion 148a in a d.irecti.on opposite from the engage portion 148b to turn the op~srating lever 148 in a clockwise direction as viewed in Fig. l9 by applying a force from the above to bring the engage portion 148b into engagement with the locking pin 147, and a second operating portion 148d which protrudes from the outer edge of the flat plate portion 148a in the direction opposite from the engage portion 148b to turn the operating lever 148 in a counterclockwise direction as viewed in Fig. l9 by applying a force from the above to release the engagement of the engage pori:ion 1~48b with the locking pin 147.
The operating lever 148 can be turned in the clockwise direction as viewed in Fig. l9 from an opened position Po via a tight position PT to a locked position PL. The engage portion 148b is formed into an arcuate shape such that the distance from an axis of the supF~ort shaft 149 is gradually decreased as the operating lever 148 is turned in the counterclockwise direction as viewed in Fig. 19" so that the engagement of the engage portion 148b with the locking pi.n 147 is started in response to the turning movement of the operating lever 148 from the opened position Po to the tight position PT, and the locking pin 147 is pulled nearer to ~~radually compress the resilient member 136 , as the operating lever 1.48 is turned about the support shaft 149 in the clockwise. direction as viewed in Fig. 19 from the tight position PT to the locked position PL.
When an operating force has been applied to the first operating portion 7.48c to turn the operating lever 148 to the locked position PL, the locking pin 147 and the engage portion 148b are brought into friction engagement with each other by the large resilient forcc: exhibited by the resilient member 136 and thus, the operating' lever 148 is stopped at the locked position PL, unless the: operating force is applied to the operating lever 1 ~~ 8 .
An elongated. bore 151 having an arcuate shape about the axis of the support shaft 149 is provided in the flat plate portion 148a of th.e operating lever 148. On the other hand, a connecting rod 1!i2 is turnably connected at its upper end to the other end of the lever 143 in the first lock means 141 and extends downwards , with .a lower end of the connecting rod 152 being engaged in t:he elongated bore 151. The length of the connecting rod 152 is set , so that when the operating lever 148 of the second lock means 142 is in the locked position PL when the first lock means 141 is in the locked state, a lower end of the connecting z~od 152 is in a position corresponding to an upper end of the el.ongatE:d bore 151, so that the unlocking of the first lock means 141 .LS impossible, and when the operating lever 148 of the second lock means 142 is in the tight position PT with the first lack means 141 being in the locked state, the lower end of the connecting rod 152 is in a position corresponding to a :Lower E:nd of the elongated bore 151, so that the unlocking of the first lock means 141 is possible, and further, when the operating lever 148 of the second lock means 142 has been turned to the opened position Po, the lever 143 is pushed upwards against the spring force of the torsion spring 146 to forcibly un:Lock tlhe first lock means 141.

According to the fourth embodiment , the first lock means 141 provided between the saddle post 22 and the rear frame 121 of the components of thE: vehicle body frame structure Fz and the second lock means 142 provided between the bottom pipe 24 5 and the saddle post: 22 arcs operatively connected to each other, so that the locked stat<~ of the first lock means 141 can be maintained in response to the locking operation of the second lock means 142, and the first lock means 141 can be unlocked in response to the unlocking operation of the second lock means 10 142.
Therefore, i.t is necessary to maintain the relative positions of the saddle post 22 and the rear frame 121 as well as between the bottom pipe 24 and the saddle post 22 in the bicycle mode, due t:o the 'vehicle body frame structure F2 being 15 of a simple arrangement comprising the handle post 21, the saddle post 22 , the rear frame 121, the bottom pipe 24 and the link pipe 122 which ~~re turnably connected together through four pivots 72, 126, 12~~ and 130, as described above. However, in response to the locking operation of the second lock means 142 20 of the first and se~~ond lock means 141 and 142, the first lock means 141 is also ma=Lntained in the locked state, and in response to the unlocking operation of the second lock means 142, the first lock means 141. is unlocked, whereby the locking operation and the unlocking operation can be facilitated extremely.
25 Although the embodiments of the present invention have been described in detail, :it will be understood that the present invention is not ~_imited to the above-described embodiments, and various modi:Eications in design may be made without departing from thE: spirit and scope of the invention defined in claims.
For example , the present invention has been described as applied to the tricycle used also as the cart in each of the embodiments, but the present invention is applicable to a tricycle which is not used as a cart.
The present invention is also applicable not only to a tricycle driven by a human power, but also to a tricycle including a power source, or a tricycle including a power source assisted by a human power.

Claims

1. A tricycle including a pair of left and right front steerable wheels supported at a front portion of a vehicle body frame structure , and a single rear drivable wheel supported at a rear portion of the vehicle body frame structure, wherein said tricycle comprises a cylindrical handle post which is fixedly mounted at a front end of said vehicle body frame structure and which turnably supports a steering shaft connected to a steering handlebar, left and right upper links which are integrally connected to each other and pivotally supported at an upper end of said handle post , left and right lower links which are integrally connected to each other and pivotally supported at a lower end of said handle post, a cylindrical left leg member which is pivotally supported at upper and lower opposite ends thereof to outer ends of said left upper and lower links, a cylindrical right leg member which is pivotally supported at upper and lower opposite ends thereof to outer ends of said right upper and lower links, a left front wheel support member rotatably supported on said left leg member, a right front wheel support member rotatably supported on said right leg member, said left front wheel being supported on said left front wheel support member and disposed immediately below said left leg member, said right front wheel being supported on said right front wheel support member and disposed immediately below said right leg member, and a steering operatively-connecting means being disposed below said handle post and both said leg members for operatively connecting said steering shaft and said left and right front wheel support members to each other.

2 . A tricycle including a pair of left and right front steerable wheels supported at a front portion of a vehicle body frame structure, and a single rear drivable wheel supported at a rear portion of the vehicle body frame structure, wherein said tricycle comprises a cylindrical handle post which is fixedly mounted at a front end of said vehicle body frame structure and which turnably supports a steering shaft connected to a steering handlebar, left and right upper links which are independent from each other and pivotally supported at an upper end of said handle post , left and right lower links which are independent from each other and pivotally supported at a lower end of said handle post , a cylindrical left leg member which is pivotally supported at upper and lower opposite ends thereof to outer ends of said left upper and lower links , a cylindrical right leg member which is pivotally supported at upper and lower opposite ends thereof to outer ends of said right upper and lower links, a left front wheel support member turnably supported on said left leg member, a right front wheel support member turnably supported on said right leg member, left and right connecting frames which are fixedly mounted on at least ones of : said left and right upper links; and said left ands right lower links, respectively, a connecting member which is turnably connected at opposite ends thereof to said connecting frames , said left front wheel being supported on said left front wheel support member and disposed immediately below said left leg member, said right front wheel being supported on said right front wheel support member and disposed immediately below said right leg member, and a steering operatively-connecting means being disposed below said handle post and both said leg members for operatively connecting said steering shaft and said left and right front wheel support members to each other .

3 . A tricycle according to claim 1 or 2 , further including a left upright attitude maintaining means which is provided between said handle post and one of said left upper and lower links for exhibiting a spring force for returning said handle post to upright attitude thereof in response to said handle post inclining leftwards from the upright attitude, but for avoiding exhibiting a spring force, when said handle post is inclined rightwards from the upright attitude, and a right upright attitude maintaining means which is provided between said handle post and one of the right upper and lower links for exhibiting a spring force for returning said handle post to upright attitude thereof in response to said handle post inclining rightwards from the upright attitude, but for avoiding exhibiting a spring force, when said handle post is inclined leftwards from the upright attitude, and a spring force for biasing said handle post in the direction toward the upright attitude being applied to said left and right upright attitude maintaining means even in the upright state of said handle post .