1313651 九、發明說明： 【發明所屬之技術領域】 行車之 本發明係'與自行車有關，特別是有關於一種自 單向傳動機構。 5 15 【先前技術】 如第七圖所示之-種自行車車輪之棘輪裝置(7〇)，复 =含有「内輪(72)、一棘輪(74)與二棘爪(76)，其中内輪(乃)固 定於自行車後車輪之—輪軸⑽），並可與輪軸_同步旋轉 輪(74)套設内輪(72)，且棘輪(74)的外周面複於 ⑽）’用以供自行車之—鏈條裝設，而棘輪剛内周:; 有複錄齒(744)，各棘齒(744)之間具有一齒槽(746);各棘爪⑽ 連接於内輪(72)，並嵌入棘輪(74)之齒槽(746)中。 當自行車騎士利用雙腳踩動自行車之二踏板時，連接於各 踏板之-曲柄會經由鏈條帶動棘輪(74)以逆時鐘方向旋轉，棘 輪(74)將透過齒槽(746)推抵二棘爪(76)，使二棘爪(76)推動内輪 ⑽’讓内輪(72)與輪軸(8G)_起旋轉，用以驅使自行車前進， 而當自行車下坡行駛時，若停止踩動踏板，輪軸_會超越棘 輪(74) ’使二棘爪(76)滑過棘輪(74)内周面的棘齒(744)齒背，使 自行車後車輪達到自由空轉的目的。 然而，上述棘輪裝置(7〇)係利用齒槽(746)推抵棘爪(76) 的尖端’用以驅使自行車前進，但是齒槽(746)與棘爪⑽ 之間係僅有點與點的接觸，使得棘爪(7 6)所傳遞的力量相當 有限□此自行車可士必須施予較大的踩動力量，才能驅使 自行車前進。 20 1313651 【發明内容】 本發明之主要目的在於提供一種自行車之單向傳動機 構，其可有效傳遞自行車騎士踩動的力量。 5 10 15 為達成上述目的，本發明所提供之自行車之單向傳動 機構包含有-傳詩、件、—雜件 該傳動件具有-軸孔：該魅彼目η:後致展柱， -導引部，其中該等容:、有稷數谷置槽與複數第 置槽係以該驅動件之車' 繞於該驅動件之周緣，各該容置槽的槽面呈傾斜狀，' = 該容置槽的一側邊至該傳動件的距離小 ^ 一側邊至該傳動件的距離， μ合置彳曰的另 槽；該彈性件設於該驅動件/甘4 — ¥引部對應各該容置 該第二導引部對應各該第一導弓二有二導引部’各 地容置於各該容置槽，盆，各该滾柱分別可滾動 位部分別與各該第二導;;=別具有-定位部，該二定 細主可於各該容置槽t;c部結合’使各 導引部而於-第-位置鱼_4各^—導引部與各該第二 柱滾動至該第-位置時，位置之間滾動；當各該滾 件之内周面及各該容置槽的样外周面分別與該傳動 置時，各該滾柱的外滾柱滾動至該第二位 該容置槽之槽面鬆離，使 /·件之内周面，而與各 在本發明一較佳實施例空轉。 該彈性件之第二導引部八，5亥驅動件之第—導引部與 乃為凹槽，且該驅動件之凹槽周 20 1313651 壁與該純叙㈣辣狀1 ㈣分別為凸柱，該二凸挺亦分別至錐狀，2=二 別插設於該二凹射，並可相互齡，使 ^ ，凸柱而沿著該二凹槽在該第一 凌:= 滾動。 中一位置之間 藉此，本發明 動件與該驅動件之間的接:動 1Q :=面的接觸，使得本發明可有效傳遞:= 【實施方式】 兹配合圖式列舉以下較佳實施例 構及功效進行詳細說明；复 明之結 15 麓-图心―，、情關式先間要說明如下： 弟圖係本毛明—較佳實施例之立 第二圖係本發明—_ 刀解圖， 圖； X Μ貫施綱提供之縣件的後視 f三=係本發明—較佳實施例之讀Μ合圖； ΐ:Ξ::ίΓΓ較佳實施例之部分級合剖視圖； 弟圖糸柄明—較佳實施例組合後之部分後 以及 第六圖係一放大圖’主要顯示本發明-較佳實施例所 提供之雜在容賴巾滚動之狀態。幸乂仏補所 請爹閱第-圖，係本發明一較佳實施例所提供之自行 6 20 1313651 車之單向傳動機構(10)，其包含有一傳動件(20)、—驅動件 (3〇):—彈性件(40)、-定位環(50)與七個滾柱(60): 該傳動件(20)中央具有一貫穿前後兩側之軸孔(2亥 •傳動件(2_相面係與該自行車後車輪之—餘結合，= • 3 5亥傳動件(20)可與該輪轂同步轉動。 請配合參閱第二圖，該驅動件(3〇)具有一軸部(3ι),該 φ 軸部(31)穿設於該傳動件(20)之轴孔(22)中，其—端具有複 數向外大出之鏈輪齒(32)，該等鏈輪齒(32)係以該軸部(31) 之軸向為圓心環繞於該軸部(31)，用以供自行車之—鏈條裝 10設；該軸部(31)的另一端具有一嵌槽(33)，該轴部(31)於= 等鏈輪齒(32)與該嵌槽(33)之間設有七個容置槽(34)與一環 垣(35)，各該容置槽(34)係以該軸部(31)之軸向為圓心環繞 於該轴部（31)之周緣，各該容置槽（34)具有—第一側邊 (342)、一第二側邊(344)與一連接該第一側邊(342)與該第二 .I5侧邊(344)之槽面(346) ’其中該槽面(346)呈傾斜狀，使各該 脅 第一側邊(342)至該傳動件(20)之内周面的距離$ 1)小於各 該第二側邊(344)至該傳動件(2〇)之内周面的距離(L2)，如第 六圖所示；該環垣(35)鄰接於該等容置槽(34)，並位於該軸 部(31)靠近該等鏈輪齒(32)的位置，該環垣(35)相對該等容 2〇置槽（34)之一側面具有七個第一導引部(36)，如第二圖所 示’各該第一導引部(36)係為凹槽，每一個第一導引部(36) 對應每一個容置槽(34)，使各該第一導引部(36)之前端(362) 與各該容置槽(34)之第一側邊(342)位於同一側，而各該第 一導引部(36)之後端(364)則與各該容置槽(34)之第二側邊 7 1313651 (344)位=同-側’另外，各該第—導引部⑽的周壁呈錐 狀如第二圖所不，各該第一導引部⑽周壁之錐角介於 30度〜40度之間，在本實施例中為％度。 • 該彈性件⑼)係為—碟形彈簧，其周緣具有七個第二導 _ 5引4(42)’各遠第二導引部⑽為凹槽，各該第二導引部(42) 的前後兩端(422)(424)分別對應各該第一導引部(36)的前後 •，端(362)(364)。各該第二導引部(42)之懸亦呈錐狀，如 第二圖所示，各該第二導引部(42)周壁之錐角在本實施例中 亦為35度。 1〇 該定位環(50)嵌設於該驅動件(30)之嵌槽(33)中，並抵 接於該彈性件(40)，用以將彈性件(4〇)固定於該驅動件(3〇)。 请配合參閱第五圖，各該滾柱(6〇)容置於該驅動件(3〇) 之各該容置槽(34)中，並可沿著該槽面（346)於各該第一側 邊(342)與各該第二側邊(344)之間滾動。各該滾柱(6〇)的兩 書15端分別具有一定位部(62) ’各該定位部（62)係為錐狀之凸 ' 柱，如第三圖所示，各該定位部(62)的錐角在本實施例中為 35度。該二定位部(62)分別插設於各該第一導引部(36)與各 5亥第二導引部(42)中，並可受該彈性件(4〇)的彈力作用，除 了使各該滾柱(60)的外周面可分別與各該第一導引部（36) 20與各该第二導引部(42)的周壁嗜合之外，亦可使各該滾柱 (60)在各該第一導引部(36)與各該第二導引部(42)之間有活 動的空間。藉此，當各該滾柱(60)沿著各該容置槽(3句之槽 面(346)滾動時，將會利用該二定位部(62)沿著各該第一導 弓ί部(36)與各該第二導引部(42)而於一第一位置(ρι)與一第 1313651 二位置(P2)之間滾動，如第六圖所示，當各該滾柱(6〇)位於 該第一位置(P1)時，各該滾柱(60)的外周面分別與該傳動件 (20)之内周面及各該容置槽(34)之槽面(346)嚙合，當各該滾 • 柱(6〇)位於該第一位置(P2)時，各該滾柱(6〇)的外周面係與 5該傳動件(2〇)之内周面嚙合，而與各該容置槽(34)之槽面 (346)鬆離。 ^ 經由上述結構，請配合參閱第六圖，當自行車騎士 踩動該自行車之二曲柄，使該二曲柄經由該鏈條帶動該 驅動件（30)轉動時，各該滾柱(6〇)會朝各該第一導引部 ίο (36)與各該第一導引部(42)的前端（362)(422)滾動，由於 各§亥容置槽（34)的第一侧邊(342)至該傳動件（2〇)之内周 面的距離(L1)小於各該容置槽（34)的第二側邊(344)至該 傳動件(20)之内周面的距離(L2)，且各該第一導引部（36) 與各§玄第一導引部（42)的前端（362)(422)與各該容置槽 .15 (34)的第一側邊(342)位於同—側，使各該滾柱(6〇)滾動至 • 該第一位置(pl)時，各該滾柱(60)的外周面會分別與該傳 動件（20)之内周面與各該容置槽（34)之槽面（346)嚙合，使 該驅動件（30)可利用各該滾柱（60)帶動該傳動件（20)轉 動，用以驅使該自行車前進。當該自行車行駛至下坡時， 20若自行車騎士停止踩動二踏板，使該驅動件（30)停止不 動，該傳動件(20)會持續轉動並藉由摩擦力帶動各該滾柱 (60)朝各該第一導引部（36)與各該第二導引部（42)的後端 (364)(424)滾動，當各該滾柱（6〇)之定位部（62)滾動至該 驅動件（30)之第一導引部（26)與該彈性件（4〇)之第二導引 9 1313651 部㈣的後端(3導24)時，各該滚柱 位置㈣’此時，各該滾柱_之相面與該傳^2弟〇): =周面^相互#，而與各該容置槽(34)之槽面⑽)鬆 離二使各遠滾柱(60)與各該容置槽(34)之槽面(346)之間會產 ’如此—來’各該滾柱(6G)會受到該傳動件(2〇) 、夺、、灵轉動而處於自由空轉之狀態。 ⑽藉^1纟發明之單向傳動機構⑽利用該傳動件 :驅動件(3〇)與各該滾柱(6〇)之間的接觸，以驅使 該:動:自由空轉’而且’該傳動件⑽、 總，你〜）一各5亥滾柱（6〇)之間都是整個面與面的接 旦於仃車騎士在踩動踏板的時候，可有效傳遞力 里w輪而較為輕鬆地驅使自行車前進。 1313651 【圖式簡單說明】 第一圖係本發明一較估 〜一 奴佳實把例之立體分解圖。 第一圖係本發明—輕供垂 平又仏μ她例所提供之驅動件的後視 圖。 第三圖係本發明—私； 卜 車乂佳實如例之立體組合圖。 第四圖係本發明— α竿以土戶、施例之部分組合剖視圖。 第五圖係本Ίχ明一^ ^ Vs I Ζ Α /Λ 半以土男、靶例紐合後之部分後視圖。 " 大圖，主要顯示本發明一較佳實施例所 提供之滾柱在容置槽中滾動之狀態。 第七圖係習用自行車車輪之棘輪裝置的示意圖。 151313651 IX. Description of the invention: [Technical field to which the invention pertains] The present invention relates to bicycles, and more particularly to a self-directional transmission mechanism. 5 15 [Prior Art] As shown in Figure 7, the ratchet device (7〇) of the bicycle wheel, complex = contains "internal wheel (72), a ratchet (74) and two pawls (76), of which the inner wheel ( Is fixed to the rear wheel of the bicycle - the axle (10), and can be fitted with the inner wheel (72) with the axle _ synchronous rotating wheel (74), and the outer peripheral surface of the ratchet (74) is used for the bicycle (10)) The chain is installed, and the ratchet is just inside:: there is a recording tooth (744) with a tooth groove (746) between each ratchet (744); each pawl (10) is connected to the inner wheel (72) and is embedded with a ratchet ( 74) in the slot (746). When the bicyclist uses the two feet to pedal the pedal of the bicycle, the crank connected to each pedal will rotate the ratchet (74) in the counterclockwise direction via the chain, and the ratchet (74) will Pushing the two pawls (76) through the slots (746), causing the two pawls (76) to push the inner wheel (10) to rotate the inner wheel (72) and the axle (8G) to drive the bicycle forward, and when the bicycle is under When driving on a slope, if the pedal is stopped, the axle _ will overtake the ratchet (74) 'slide the two pawls (76) over the back of the ratchet (744) of the inner circumferential surface of the ratchet (74), so that the rear wheel of the bicycle is free. The purpose of the rotation. However, the above ratchet device (7〇) uses the tooth groove (746) to push against the tip end of the pawl (76) to drive the bicycle forward, but only between the tooth groove (746) and the pawl (10) A little bit of contact with the point, the force transmitted by the pawl (76) is quite limited. The bicycle must be given a large amount of stepping power to drive the bicycle forward. 20 1313651 [Summary] The main purpose of the present invention The invention provides a one-way transmission mechanism for a bicycle, which can effectively transmit the force of the bicycle rider. 5 10 15 In order to achieve the above object, the one-way transmission mechanism of the bicycle provided by the invention comprises: a poem, a piece, a miscellaneous The transmission member has a shaft hole: the charm η: a rear exhibition column, a guiding portion, wherein the equal volume: a plurality of valleys and a plurality of first slots are used for the driving member of the vehicle Around the circumference of the driving member, the groove surface of each of the accommodating grooves is inclined, '= the distance from one side of the accommodating groove to the transmission member is small ^ the distance from one side to the transmission member, The other slot is placed; the elastic member is disposed on the driving member/甘4 Corresponding to each of the second guiding portions, the first guiding bows and the two guiding portions are respectively disposed in the respective receiving slots, the basins, and the rollers are respectively rotatable and respectively The second guide;; = has a positioning portion, the two fixed thin masters can be used in each of the receiving slots t; the c portion is combined with 'the respective guiding portions and the - the first position fish_4 each guide When the second column and each of the second columns are rolled to the first position, the position is rolled; when the inner circumferential surface of each of the rolling elements and the outer circumferential surface of each of the receiving grooves are respectively coupled to the driving, each of the rollers The outer roller rolls to the second groove of the accommodating groove to loosen the inner peripheral surface of the member, and idly rotates with each of the preferred embodiments of the present invention. The second guiding portion of the elastic member, the first guiding portion of the 5 hai driving member is a groove, and the wall of the groove 20 1313651 of the driving member is convex with the pure (four) spicy shape 1 (four) The column, the two protrusions are also tapered to the shape, 2 = two are inserted in the two concave, and can be mutually aged, so that the ^, the column and the two grooves along the first groove: = rolling. Between the one position, the connection between the moving member and the driving member of the present invention: the contact of the moving 1Q:= surface, so that the present invention can be effectively transmitted: = [Embodiment] The structure and function are described in detail; the knot of the rehearsal 15 麓-图心-, and the relationship between the first and the second are as follows: The younger picture is the same as the first embodiment of the preferred embodiment of the present invention - _ knife solution The rear view of the county article provided by the X Μ 施 = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =糸 明 — — — 较佳 — — — — — — — 较佳 较佳 较佳 较佳 较佳 较佳 较佳 较佳 较佳 较佳 较佳 较佳 较佳 较佳 较佳 较佳 较佳 较佳 较佳 较佳 较佳 较佳 较佳 较佳 较佳 较佳 较佳Fortunately, please refer to the first drawing, which is a one-way transmission mechanism (10) of a self-propelled 6 20 1313651 vehicle according to a preferred embodiment of the present invention, which comprises a transmission member (20) and a driving member ( 3〇):—elastic member (40), positioning ring (50) and seven rollers (60): The transmission member (20) has a shaft hole extending through the front and rear sides (2 hai transmission parts (2) The _phase system is combined with the rear wheel of the bicycle, and the • 3 5 hai transmission member (20) can rotate synchronously with the hub. Please refer to the second figure, the driving member (3 〇) has a shaft portion (3 ι) The φ shaft portion (31) is disposed in the shaft hole (22) of the transmission member (20), and has a plurality of sprocket teeth (32) that are outwardly enlarged, and the sprocket teeth (32) The shaft portion (31) is surrounded by the axial direction of the shaft portion (31) for the bicycle-chain assembly 10; the other end of the shaft portion (31) has a recessed groove (33) The shaft portion (31) is provided with seven accommodating grooves (34) and a ring cymbal (35) between the sprocket teeth (32) and the recessed groove (33), and each of the accommodating grooves (34) Surrounding the circumference of the shaft portion (31) with the axial direction of the shaft portion (31) as a center, each of the accommodating grooves (34) has - first a side edge (342), a second side edge (344) and a groove surface (346) connecting the first side edge (342) and the second .I5 side edge (344), wherein the groove surface (346) Tilting such that the distance (1) of each of the first side edges (342) of the flank to the inner circumferential surface of the transmission member (20) is smaller than each of the second side edges (344) to the transmission member (2〇) The distance (L2) of the inner circumferential surface is as shown in the sixth figure; the ring cymbal (35) is adjacent to the accommodating grooves (34), and is located at the shaft portion (31) adjacent to the sprocket teeth (32) a position, the ring cymbal (35) has seven first guiding portions (36) on one side of the one of the equal volume 2 grooving grooves (34), as shown in the second figure, each of the first guiding portions ( 36) is a groove, each of the first guiding portions (36) corresponding to each of the accommodating grooves (34), so that the front end (362) of each of the first guiding portions (36) and each of the accommodating grooves ( 34) The first side edge (342) is located on the same side, and each of the first guiding portion (36) rear end (364) and each of the receiving groove (34) second side edge 7 1313651 (344) In addition, the peripheral wall of each of the first guiding portions (10) has a tapered shape as shown in the second figure, and the peripheral wall of each of the first guiding portions (10) has a taper angle of between 30 degrees and 40 degrees. in In this embodiment, the degree is %. • The elastic member (9) is a disc spring having seven second guides 5 (42)' each of the distal second guides (10) as grooves, each of which The front and rear ends (422) (424) of the second guiding portion (42) respectively correspond to the front and rear ends (362) (364) of the first guiding portion (36). The suspension of each of the second guiding portions (42) is also tapered. As shown in the second figure, the taper angle of the peripheral wall of each of the second guiding portions (42) is also 35 degrees in this embodiment. The positioning ring (50) is embedded in the slot (33) of the driving member (30) and abuts against the elastic member (40) for fixing the elastic member (4〇) to the driving member. (3〇). Please refer to the fifth figure, each of the rollers (6 〇) is accommodated in each of the accommodating grooves (34) of the driving member (3 〇), and along the groove surface (346) A side edge (342) rolls between each of the second side edges (344). The two ends 15 of each of the rollers (6 〇) respectively have a positioning portion (62) 'each of the positioning portions (62) is a tapered convex column, as shown in the third figure, each of the positioning portions ( The taper angle of 62) is 35 degrees in this embodiment. The two positioning portions (62) are respectively inserted into each of the first guiding portion (36) and each of the second guiding portions (42), and can be subjected to the elastic force of the elastic member (4〇), except The outer peripheral surface of each of the rollers (60) may be associated with each of the first guiding portions (36) 20 and the peripheral wall of each of the second guiding portions (42), and each of the rollers may be (60) There is a space between each of the first guiding portion (36) and each of the second guiding portions (42). Thereby, when each of the rollers (60) rolls along each of the accommodating grooves (the three-slot groove surface (346), the two positioning portions (62) are used along the first guiding bow portions. (36) rolling with each of the second guiding portions (42) between a first position (ρι) and a 1313711 two position (P2), as shown in the sixth figure, when each of the rollers (6)位于) when the first position (P1) is located, the outer circumferential surfaces of the rollers (60) respectively mesh with the inner circumferential surface of the transmission member (20) and the groove surface (346) of each of the accommodating grooves (34) When each of the rollers (6 〇) is located at the first position (P2), the outer peripheral surface of each of the rollers (6 〇) meshes with the inner peripheral surface of the transmission member (2 〇), and The groove surface (346) of each of the accommodating grooves (34) is loose. ^ With the above structure, please refer to the sixth figure, when the bicycle rider steps on the two cranks of the bicycle, so that the two cranks drive the drive through the chain. When the member (30) is rotated, each of the rollers (6〇) will roll toward the first guiding portion ίο (36) and the front end (362) (422) of each of the first guiding portions (42) due to The distance (L1) between the first side edge (342) of each of the hurong slots (34) to the inner circumferential surface of the transmission member (2〇) is small a distance (L2) from a second side edge (344) of each of the receiving slots (34) to an inner circumferential surface of the transmission member (20), and each of the first guiding portions (36) and each of the § Xuandi A front end (362) (422) of a guiding portion (42) is located on the same side as a first side edge (342) of each of the receiving slots .15 (34), so that each roller (6〇) is rolled to In the first position (pl), the outer circumferential surface of each of the rollers (60) is respectively engaged with the inner circumferential surface of the transmission member (20) and the groove surface (346) of each of the accommodating grooves (34). The driving member (30) can use the rollers (60) to drive the transmission member (20) to rotate to drive the bicycle forward. When the bicycle travels downhill, 20 if the bicycle rider stops stepping on the two pedals The driving member (30) is stopped, and the transmission member (20) continuously rotates and drives each roller (60) toward each of the first guiding portions (36) and the second guiding portion by frictional force. The rear end (364) (424) of the lead portion (42) rolls, and when the positioning portion (62) of each of the rollers (6) rolls to the first guiding portion (26) of the driving member (30) When the second guide 9 1313651 of the elastic member (4〇) is at the rear end (3 guide 24) of the portion (4), each of the rollers Position (4) 'At this time, each of the rollers _ the opposite side and the pass ^ 2 sister 〇): = circumferential surface ^ mutual #, and the groove surface (10) of each of the accommodating grooves (34) loosen two Between the distal roller (60) and the groove surface (346) of each of the accommodating grooves (34), the roller (6G) will be subjected to the transmission member (2 〇), The spirit turns and is in a state of free idling. (10) The one-way transmission mechanism (10) of the invention utilizes the transmission member: contact between the driving member (3〇) and each of the rollers (6〇) to drive the movement: freely idling and 'the transmission Pieces (10), total, you ~) a 5 hp roller (6 〇) between the entire face and the face of the 仃 仃 仃 仃 骑士 骑士 骑士 骑士 骑士 骑士 骑士 骑士 骑士 骑士 骑士 骑士 骑士 骑士 骑士 骑士 骑士 骑士 骑士 骑士 骑士 骑士 骑士 骑士 骑士 骑士 骑士 骑士 骑士 骑士The ground drives the bicycle forward. 1313651 [Simple description of the drawing] The first figure is an estimated version of the present invention. The first figure is a rear view of the drive member provided by her example. The third figure is a three-dimensional combination diagram of the present invention-private; The fourth figure is a cross-sectional view of a partial combination of α竿 in the case of a household and a case. The fifth picture is a partial rear view of the original ^ ^ Vs I Ζ Α / Λ half of the male and the target. " Larger view, mainly showing the state in which the roller provided by a preferred embodiment of the present invention rolls in the accommodating groove. The seventh figure is a schematic view of a ratchet device for a bicycle wheel. 15
【主要元件符號說明】 單向傳動機構(10) 驅動件(30) 嵌槽(33) 第二側邊(344) 傳動件(20) 軸部(31) 容置槽(34) 軸孔(22) 鏈輪齒(32) 第一側邊(342) 第一側邊至该傳動件之内周面的距離(L1) 第一側邊至δ玄傳動件之内周面的距離(匕2) 環垣(35) 第一導引部(36) 後端(364) 彈性件(4〇) 前端(422) 後端(424) 滾柱(60) 定位部(62) 第二位置(P2)間距(d) 槽面（346) 前端(362) 第二導引部(42) 定位環(50) 第一位置(P1) 20[Main component symbol description] One-way transmission mechanism (10) Drive member (30) Insert groove (33) Second side (344) Transmission member (20) Shaft portion (31) accommodating groove (34) Shaft hole (22 Sprocket (32) First side (342) Distance from the first side to the inner circumference of the transmission (L1) Distance from the first side to the inner circumference of the δ mysterious member (匕2)垣 (35) First guide (36) Rear end (364) Elastic member (4〇) Front end (422) Rear end (424) Roller (60) Positioning part (62) Second position (P2) spacing (d) Groove surface (346) Front end (362) Second guide (42) Positioning ring (50) First position (P1) 20