M352497 八、新型說明： 【新型所屬之技術領域】 本案係關於-種㈣_車，騎疊購_具有輔雜及停車 置。 【先前技術】 根據本案㈣人之研發及實作經驗魏，欲將傳統的折疊式自行車於折疊 •後充當購物推車使用時，面臨以下各種問題。 _ -、傳統折_行車於車架主桿設關節結構，該關節結構以單—極抽做 I為㈣點’自行車以該轉折點對折後d字形，前後車身之間具有一夾角，前 後輪者地但科行，以致於自行車於折纽難以推動。 二、 折疊後的自行車於前行移動時，前輪會受把手之影響而偏擺，造成車 體移動時之阻礙。 早 三、 折養後的自行車於兩輪正轉之前行移動時，曲柄及腳踏並不會隨 ==兩輪為逆轉之後退移動時，曲柄及腳踏即隨之逆向轉動，進 構成卡擋阻礙，而使車體無法動彈。 干牙 齡四一種具有辅助輪的折#自行車，_體析纽將輔助輪著地，與 兩輪形成三點支擇，而可做為購物推車使用。但展開車體騎行時，若未將 輪離地，齡增加行進時之截及阻礙，造成行車安全問題。 五、折#後的自行車貨架或置物籃會 車體前傾），產生與地面傾斜之狀況，導致貨物放置於1上^輪較短而使 【新型内容】 本案主要概前技射所述的問題提編方案。關於㈣ 後退移動時曲柄腳踏與車身卡播阻礙的問題，已於一前案 幽纖「自嫩卿」）巾__，綠衛第 5 M352497 另外，關於車體折疊後兩輪非平行，以及車體折叠後 本案創作人業已提出解決方案，並另案申請(新 ^擺^等問題， 「折疊式購物自行車」）。 中月案或第97207035號 本案之目的其係以簡單而容易操作的方案控制—辅助 易完成輔助輪之起落及麟等動作 ，Μ者可輕 、他 該辅助輪必需於離地狀態時自行車妒可 被騎行，以避免輔助輪影響行車安全性。 早《了 本案之目祕提錄助輪及停車柱 功能，而糊方便性。 方案捕助輪可兼具停車柱的 本案之目_提出漏槪停紐之複合轉，其具树賴作之優點， 而方便使用。 ” 〃本案之目的係提出該自行車之貨架與車架間具有一調整機構，俾以活動調 -郎該貨架之安裝角度，使貨物能於自行車及購物車使用轉換狀態時，仍能 放置。 本案達成上述目的之主要技術包括： 。於自行車之車架主軸設-輔助輪，該輔助輪著地時干涉該自行車之曲柄的 嚤迴轉空間’該獅輪離地咖脫離賴柄的迴轉空間，據此，在輔助輪著地的 情況下該自行車無法被騎行，以避免輔助輪影響行車安全性。 【實施方式】 為便於說明本案於上述新型内容一攔中所表示的中心思想 ，茲以具體實施 例表達。實施例中各種不同物件及其變形量或位移量係按適於例舉說明之比 例，而非按實際元件的比例予以繪製，合先敘明。 第一圖表示一折叠式自行車，該車體之型式僅便於說明本案而已，本案主 要技術可實現於各式車體，並不限於圖例所示之型式。 本案主要技術涉及一設於車架主軸10之輔助輪3〇。如第一圖至第五圖，包 6 M3 52497 括-上座31、-支標桿32、至少一滚輪33以及一彈菁34。該上座^直有一上固 定部川及-下固定部315，該上固定部311用以固定於自行車之車架主抽此 後端。該下固定部315以-旋轉接點321連接該支樓桿32的頂端，該支樓桿没的 底端設上述之滾輪33。該上座31以及該支撐桿32各具有一彈菁接點训322， .用以連接上述之彈簧34。該下固定部315的左右邊各具有_侧限位部扣。 • 該支擇桿32以其旋轉接點321而使其可於-第-位置及—第二位置定止，並 •且可於該第-位置及第二位置間移動。所述的帛一位置係指該支樓桿32以該滾 -輪33支立於地面，第二位置係指該支撐桿32使該滾輪於離開地面。該支樓桿於 #於第-位置及第二位i時分職上述的侧限位部312所擔止。該支揮桿32於第一 位置及第二位置時，上述的二彈簧接點316,322及旋轉接點功呈三角形之三頂 點對應，使該彈簧34之拉力作用於該支樓桿32及該上細，使支撑桿％抵止於 該側限位部312,323而被定位。 »亥上固疋部311及該下固定部315呈-預定角度之幫折狀，當該支撑桿32在 第一位置(亦即滾輪33支立於地面)時，受該下固定部315的導引作用，使該支揮 桿32往遠離該車架主轴1〇之方向傾斜，進而干涉該自行車曲柄13的迴轉空間， 籲使該曲柄13無法順利轉動。當支撑桿&在第二位置(亦即滾輪π離開地面時）， 該支標桿32即脫離該自行車曲枘13的迴轉空間，使曲柄13得以轉動。將自行車 折疊做為祕推車時，舰該支撐桿32在I位置，雜33著軸前輪15及後 輪16形成三點支撐。欲騎用自行車時，則必需使該支撐桿32在第二位置，滾輪 33離地，否則曲柄即無法迴轉，故此一方案即可故可完全避免輔助輪30影響行 車安全性的問題。以足部施力於該支撐桿32即可控制該支撐桿32於第一位置及 第二位置切換，方法簡單且省力。 該上座31具有一用以輔助該支撐桿32定位於該第一位置或該第二位置之支 撐桿定位結構。 7 M352497 . 該支樓桿定位結構如第二圖及第三圖，該下固定部315具有-可對該支樓桿 32構成移動頓點的凸點結構317，關助該支律糊在第—位置及第二位置^ 位。使用者以足部控綱支揮桿32通過該凸點結構317時必需略微的加大施力^ 如第六圖及第七圖，該支懈32的底端設-轉連接一滾輪 柱61 ’該轉軸60轉動預定角度，可控繼滚輪柱61著地或離地，而做為折義車 •的輔助輪或自行車的停車柱。其中，該支撐桿32以及該滾輪柱61的相對^面 -上刀別具有弧形之凹槽325以及至少一插銷62，該凹槽325的至少一端部設一定 .位孔326，該轉軸60上套設一彈簧327。向夕卜施力拉開支樓桿泣並轉動時^該^ 籲銷62可沿凹槽325移動’且該插銷62可插入該定位孔326巾將該支揮桿迫固 定。例如本案實施例亦可以二個插梢62三個定位孔326的方式以增進定位效果， 保持轉抽60穩定不晃動，即可減少轴心磨耗。 ' 如第人®及第九®，該支撐桿32的底端設_雜60 ’轉細)連接-滾輪 柱61及一知車柱63 ’該轉軸60轉動預定角度’可控制該滾輪柱61或該停車柱63 著地。該支撐桿32以及該滾輪柱61的相對接觸面上分別具有一弧形之凹槽325 以及-插銷62，該凹槽325的至少-端部設一定位孔326，該轉軸6〇上套設一彈 _簧327。向外施力拉開支撐桿32並轉動時，|亥插鎖62可沿凹槽325移動，且該插 銷62可插入該定位孔326中，將該支撐桿32固定。 上述的凹槽325可依需要而製設各種圓周角度之弧形，以便支擇桿32轉動各 種預期的角度，使滾輪柱61及停車柱63著地而發揮功能。 上述支撐桿32係一板狀結構，其可以上部的弧形口 328焊接在車體的五通管 下緣。該支摔桿32的下端緣較自行車之齒細0的下緣輪廓更低位。在滾輪柱扪 未著地的情況下而發生車體前傾時，該支_32的底齡無面碰觸而避免齒 盤80與地面撞擊，因此該支撐桿32具有保護齒盤8〇的作用。上述支撐桿％亦可 傾斜的焊接在車體的五通管，停車柱61支立於地面時，支撐桿32干涉該自行車 8 M352497 曲柄彻迴轉㈣’蝴瓣車姉地，始可翻自行車，細嫩修 如第十圖所示’由於自行轉放時為保持穩定，停車時車體係略為傾斜， 因此滾輪33之純需略高於地面’以利車__邊傾斜，但當自行車折疊 成購物車使㈣，雜33需抵地面，造縣身會麵相斜，原本平行於 地面之自行車貨架顺置物籃會因車體角度之改變而產生傾斜之狀況，導致貨 物放置於其上不穩當。因此，本創作之貨架7〇係以兩支架71可轉動裝設於車體 -輪軸處’域娜〇前端與蝴如座管或後上又)間設有—調整機構了2，該調整 機構72可活動調節該貨架70前端與車架之間距，例如其可為一活動螺桿乃，一 > 細接，藉㈣獻糊魏貨架顺 端與車架之間距，以使該貨架70可產生角度變化，以便於將貨架7〇調整至與地 面水平(上述貨架也可與置物籃結合實施）。 該調整機構72亦可如第十一圖及第十二圖所示，貨架7〇設一調整架74，該 調整架74的後端741連接於該貨架7〇的後柳，並且以該連接處為圓心而可轉 $該調整架74，而改變該調整架74與該嫌⑽夾角角度。該調整架74的前端 叹-可轉動的調整框75 ’該調整框75具有一第一框體751及一第二框體752，該 .第一框體752的長度大於該第一框體751，該調整框75係以一轉動插轴脱連接 於調整架74，並且可以轉動切換，使第―框體751或第二框體了财^該第一 框體751及該第二框體752中具有複數個調整孔76。該貨架7〇的前端具有一可彈 性移動的彈扣件77，該彈扣件77可彈扣人其中—調整孔76，例如，當自行車折 •a·成購物車使用時’因滾輪33抵觸於地面，造成車身往前方傾斜，此時即令該 彈扣件77彈扣入下位位置的調整孔76中，拉高該調整架74的前端’而使其與地 面保持水平。 復如第-圖，折疊式自行車於前又及後叉之預定位置分別設有—磁性元件 121,122 ’以便鱗體折疊時’二磁性元件121，彳22以磁力吸附，自行車折疊後 9 M352497 ，呈左右平行相對的錢輪之射具有相對連接的定位職，賭止車 前輪偏擺’而利於車體移動。另，一轉折結構14使車把手可以向車架前桿的方 向折。’因此，在車把手桿以及車架前桿的相對位置各設有一磁性元件 123,124 ’以便於吸附定位折合的車把手。 "雜本案是社述實蘭做說明，但精於此技藝者能在不讎本案精神與 範缚下做各種不fg]形式的改變。以上所舉實施例侧以綱本案而已非用以 限制本案之補。舉凡不違本案精神所從事的種種修改或變化，俱屬本案申請 -專利範圍。 •【圖式簡單說明】 第圖為自行車之平面外觀圖，表示本案之辅助輪呈離地狀態。 第二圖為本雜助輪第—實施例之域分解圖。 •第二圖為本案輔助輪第一實施例之組合外觀圖。 第四圖為自行車摺疊成購物推車之側視圖，辅助輪呈著地狀態。 第五圖為自行車之平面圖’表示本案辅助輪呈著地狀態。 第六圖為本案辅助輪複合停車柱之第二實施例平面示意圖。 鲁第七圖為本案_輪複合停車柱之第二實施例剖面示意圖。 .第八®為本案_輪複合停車柱之第三實施例平面示意圖。 第九圖為本案輔助輪複合停車柱之第三實施例剖面示意圖。 第十圖為自行車摺疊成購物推車之側視圖，並表示貨架調整之示意圖。 第十-圖為配合難購物推車之貨架實關分解圖。 第十一圖為配合摺疊購物推車之貨架實施例組合圖。 M352497 【主要元件符號說明】 10-車架主轴 311-上固定部 328-弧形口 74-調整架 121-磁性元件 312-側限位部 33-滾輪 741-後端 122-磁性元件 315-下固定部 34·彈簧 75_調整框 123-磁性元件 316-彈簧接點 60-轉軸 751-第一框體 124-磁性元件 317-凸點結構 61-滾輪柱 752-第二框體 13-曲柄 32_支撐桿 62-插梢 753-轉動枢軸 14-轉折結構 321-旋轉接點 63-停車柱 76-調整孔 15-前輪 322-彈簧接點 70-貨架 77-彈扣件 16-後輪 325-凹槽 701-後端 80-齒盤 30-輔助輪 326-定位孔 72-調整機構 31-上座 327-彈簧 73-螺桿 11M352497 VIII, new description: [New technology field] This case is related to - species (four) _ car, riding the purchase _ with auxiliary and parking. [Prior Art] According to the research and development experience of the case (4), the following problems are encountered when the conventional folding bicycle is used for folding and later serving as a shopping cart. _ -, traditional folding _ driving on the main frame of the frame set joint structure, the joint structure is made of single-pole pumping I (four) point 'bike with the turning point folded in a d-shape, the front and rear body has an angle between the front and rear wheels The land is so fast that it is difficult to promote bicycles. 2. When the folded bicycle moves forward, the front wheel will be deflected by the handle, which will hinder the movement of the car body. In the morning, when the bicycle after the recuperation moves before the two rounds of normal rotation, the crank and the pedal will not reverse with the == two rounds, and the crank and the pedal will reversely rotate, and the card will be inserted. Blocking the obstacles, so that the car body can not move. Dry teeth Age four types of bicycles with auxiliary wheels. The _ body analysis button will assist the wheel to land, and form a three-point selection with the two wheels, which can be used as a shopping cart. However, when the vehicle body is being ridden, if the wheel is not removed from the ground, the age is increased and the obstacle is hindered, resulting in driving safety problems. 5. After the bicycle ################################################################################################ Question proposal. (4) The problem of the crank pedal and the body jam is hindered when moving backwards. It has been in the case of a sneak peek "self-endering". __, Green Guard 5 M352497 In addition, the two wheels are non-parallel after folding. After the folding of the car body, the creator of the case has proposed a solution, and applied for another case (new folding pendulum, etc., "folding shopping bicycle"). The purpose of this case is the simple and easy-to-operate control of the mid-month case or the 97270035. It is easy to complete the movement of the auxiliary wheel and the action of the lining. The latter can be light, and the auxiliary wheel must be in the state of leaving the bicycle. Can be riding to avoid the auxiliary wheel affecting driving safety. Early "The secret of this case is to mention the function of the wheel and the parking column, and the convenience of the paste. The scheme catching wheel can be combined with the parking column. The purpose of this case is to make a composite transfer of the leaky stop, which has the advantages of the tree and is convenient to use. The purpose of this case is to propose that there is an adjustment mechanism between the shelf and the frame of the bicycle, and the installation angle of the shelf can be used to enable the goods to be placed when the bicycle and the shopping cart are used in the transition state. The main techniques for achieving the above objectives include: • The auxiliary frame of the bicycle frame is provided with an auxiliary wheel that interferes with the cranking space of the crank of the bicycle when the auxiliary wheel touches the ground. Therefore, the bicycle cannot be ridden in the case where the auxiliary wheel touches the ground, so as to prevent the auxiliary wheel from affecting the driving safety. [Embodiment] In order to facilitate the description of the central idea expressed in the above-mentioned novel content, the specific implementation is implemented. The various figures and their deformations or displacements in the embodiments are drawn according to the proportions which are suitable for the description, rather than the proportions of the actual components. The first figure shows a folding bicycle. The type of the car body is only convenient for explaining the case. The main technology of the case can be realized in various car bodies, and is not limited to the type shown in the legend. The technique relates to an auxiliary wheel 3〇 provided on the frame main shaft 10. As shown in the first to fifth figures, the package 6 M3 52497 includes a top seat 31, a support rod 32, at least one roller 33, and an elastic cue 34. The upper seat has an upper fixing portion and a lower fixing portion 315 for fixing the rear end of the bicycle frame. The lower fixing portion 315 connects the branch rod 32 with the rotating joint 321 . The top end of the branch pole is provided with the above-mentioned roller 33. The upper seat 31 and the support rod 32 each have an elastic engagement train 322 for connecting the spring 34. The lower fixing portion 315 Each of the left and right sides has a _ side limit portion buckle. The check rod 32 is rotatably coupled to the first position and the second position, and is configurable at the first position and The second position is moved. The first position means that the branch bar 32 is supported by the roller-wheel 33, and the second position means that the support bar 32 causes the roller to leave the ground. When the #-position and the second position i are divided into the above-described side limit portion 312, the above-mentioned swing bar 32 is in the first position and the second position, The two spring contacts 316, 322 and the rotating contact work have three vertices corresponding to the triangle, so that the pulling force of the spring 34 acts on the branch bar 32 and the upper portion, so that the support rod % is resisted by the side limiting portion 312, 323 Positioning: The upper solid portion 311 and the lower fixing portion 315 are in the shape of a predetermined angle, and when the support rod 32 is in the first position (that is, the roller 33 is supported on the ground), the lower fixing portion is received. The guiding action of the 315 is such that the swinging lever 32 is inclined away from the main shaft of the frame, thereby interfering with the rotating space of the bicycle crank 13, so that the crank 13 cannot be smoothly rotated. When the supporting rod & When the two positions (i.e., when the roller π leaves the ground), the branch lever 32 is disengaged from the swing space of the bicycle crank 13, so that the crank 13 is rotated. When the bicycle is folded into a secret cart, the support rod 32 is at the I position, and the front axle 15 and the rear wheel 16 of the miscellaneous 33 form a three-point support. When the bicycle is to be used, the support bar 32 must be in the second position, and the roller 33 is off the ground, otherwise the crank cannot be rotated. Therefore, the solution can completely avoid the problem that the auxiliary wheel 30 affects the safety of the vehicle. The support rod 32 can be controlled by the foot to apply the support rod 32 to switch between the first position and the second position, and the method is simple and labor-saving. The upper seat 31 has a support rod positioning structure for assisting the support rod 32 to be positioned in the first position or the second position. 7 M352497 . The positioning structure of the supporting pole is as shown in the second figure and the third figure. The lower fixing portion 315 has a bump structure 317 which can constitute a moving point of the branch pole 32, and the supporting rule is in the first - position and second position ^ bit. When the user passes the bump structure 32 through the bump structure 32, the user must slightly increase the force. For example, the sixth figure and the seventh figure, the bottom end of the lever 32 is connected-rotated to a roller column 61. 'The rotating shaft 60 is rotated by a predetermined angle, and can be controlled to follow the roller column 61 to the ground or off the ground, and serve as an auxiliary wheel of the falsification vehicle or a parking column of the bicycle. The support rod 32 and the opposite surface of the roller post 61 have an arc-shaped recess 325 and at least one latch 62. At least one end of the recess 325 is provided with a certain hole 326. A spring 327 is sleeved on the sleeve. When the spurs are swaying and rotating, the yoke 62 can be moved along the recess 325 and the latch 62 can be inserted into the locating hole 326 to force the sling to be fixed. For example, in the embodiment of the present invention, the two positioning holes 326 of the two insertion holes 62 can be used to improve the positioning effect, and the rotation of the rotary pump 60 can be stabilized without shaking, thereby reducing the shaft center wear. 'As for the first person and the ninth, the bottom end of the support rod 32 is set to _ 60's finer) connection-roller column 61 and a knowing column 63 'the rotation shaft 60 is rotated by a predetermined angle' to control the roller column 61 Or the parking column 63 is on the ground. The support rod 32 and the opposite contact surface of the roller column 61 respectively have an arc-shaped recess 325 and a latch 62. At least one end of the recess 325 is provided with a positioning hole 326, and the rotating shaft 6 is sleeved. A bullet _ spring 327. When the support rod 32 is pulled outwardly and rotated, the latch 62 can be moved along the recess 325, and the latch 62 can be inserted into the positioning hole 326 to fix the support rod 32. The groove 325 can be formed with various circumferential angles as needed to support the rod 32 to rotate at various desired angles, so that the roller column 61 and the parking column 63 can function to land. The support rod 32 is a plate-like structure which can be welded to the lower edge of the five-way pipe of the vehicle body by an upper curved opening 328. The lower end edge of the strut 32 is lower than the lower edge contour of the tooth 0 of the bicycle. When the vehicle body is tilted forward without the ground of the roller column, the bottom of the branch _32 has no surface contact and the toothed disc 80 is prevented from colliding with the ground, so the support rod 32 has the protection of the toothed disc 8〇. effect. The support rod % can also be obliquely welded to the five-way pipe of the vehicle body. When the parking column 61 stands on the ground, the support rod 32 interferes with the bicycle. 8 M352497 crank is rotated (four) 'butterfly rut, and the bicycle can be turned over. The delicate repair is as shown in the tenth figure. 'Because it is stable when it is transferred by itself, the car system is slightly inclined when parking, so the pure need of the roller 33 is slightly higher than the ground' to lean on the side of the car, but when the bicycle is folded into a shopping The car makes (4), the miscellaneous 33 needs to reach the ground, and the county body meets obliquely. The bicycle racks that are parallel to the ground will be tilted due to the change of the car body angle, resulting in the cargo being placed on it. Therefore, the shelf 7 of the present invention is provided with two brackets 71 rotatably mounted at the vehicle body-axle at the front end of the body and the butterfly body or the rear upper and lower sides. 72 can adjust the distance between the front end of the shelf 70 and the frame, for example, it can be an active screw, a small connection, and (4) the distance between the shelf and the frame of the shelf, so that the shelf 70 can be produced. The angle is varied to facilitate adjustment of the shelf 7 to the ground level (the shelf can also be implemented in conjunction with the storage basket). The adjustment mechanism 72 can also be arranged as shown in the eleventh and twelfth drawings. The shelf 7 is provided with an adjustment frame 74. The rear end 741 of the adjustment frame 74 is connected to the rear cane of the shelf 7 and is connected by the connection. At the center of the circle, the adjustment frame 74 can be turned, and the angle between the adjustment frame 74 and the suspect (10) is changed. The first frame 751 and the second frame 752 have a length greater than the first frame 751. The first frame 752 has a length greater than the first frame 751. The adjusting frame 75 is disconnected from the adjusting frame 74 by a rotating plug shaft, and can be rotated and switched, so that the first frame body 751 or the second frame body can be used for the first frame body 751 and the second frame body 752. There are a plurality of adjustment holes 76 in the middle. The front end of the shelf 7 has an elastically movable elastic fastener 77, which can be used to buckle the person-adjusting hole 76, for example, when the bicycle is folded into a shopping cart, On the ground, the vehicle body is tilted forward. At this time, the elastic fastener 77 is snapped into the adjustment hole 76 of the lower position, and the front end of the adjustment frame 74 is raised to keep it level with the ground. As shown in the first figure, the folding bicycle is provided with a magnetic element 121, 122 ' at a predetermined position on the front and the rear fork, respectively, so that when the scale is folded, the two magnetic elements 121, 22 are magnetically attracted, and the bicycle is folded after 9 M352497. The parallel and opposite shots of the money wheel have a relatively connected positioning position, and the front wheel yaw is swayed to facilitate the movement of the vehicle body. In addition, a turning structure 14 allows the handlebar to be folded toward the front of the frame. Thus, a magnetic element 123, 124' is provided at each of the relative positions of the handlebars of the vehicle and the front of the frame to facilitate the positioning of the folded handlebars. "Miscellaneous case is the statement of the social statement, but the skilled person can do all kinds of changes without the spirit and the norm of the case. The above-mentioned embodiments are not intended to limit the case in this case. All kinds of modifications or changes that are not in violation of the spirit of the case are the scope of the application - patent scope. • [Simple description of the diagram] The figure is a plan view of the bicycle, indicating that the auxiliary wheel of the case is off the ground. The second figure is a domain exploded view of the first embodiment of the hybrid wheel. • The second figure is a combined appearance of the first embodiment of the auxiliary wheel of the present case. The fourth picture shows a side view of the bicycle folded into a shopping cart, and the auxiliary wheel is in a ground state. The fifth picture shows the plan of the bicycle, which indicates that the auxiliary wheel of the case is in a ground state. The sixth figure is a plan view of the second embodiment of the auxiliary wheel composite parking column of the present invention. The seventh figure of Lu is a schematic cross-sectional view of the second embodiment of the present invention. The eighth embodiment is a plan view of a third embodiment of the present invention. The ninth drawing is a schematic cross-sectional view of a third embodiment of the auxiliary wheel composite parking column of the present invention. The tenth figure is a side view of the bicycle folded into a shopping cart, and shows a schematic diagram of the shelf adjustment. The tenth-figure is an exploded view of the real estate of the difficult shopping cart. The eleventh figure is a combination diagram of a shelf embodiment of a folding shopping cart. M352497 [Description of main component symbols] 10-frame spindle 311-upper fixing part 328-arc port 74-adjusting frame 121-magnetic element 312-side limiting part 33-roller 741-back end 122-magnetic element 315-lower Fixing portion 34·spring 75_adjusting frame 123-magnetic member 316-spring contact 60-rotating shaft 751-first frame 124-magnetic member 317-bump structure 61-roller column 752-second frame 13-crank 32 _ support rod 62-tip 753-rotation pivot 14-turning structure 321-rotating joint 63-parking column 76-adjusting hole 15-front wheel 322-spring contact 70-shelf 77-elastic fastener 16-rear wheel 325- Groove 701 - rear end 80 - toothed disc 30 - auxiliary wheel 326 - positioning hole 72 - adjustment mechanism 31 - upper seat 327 - spring 73 - screw 11