1231791 玖、發明說明 【發明所屬之技術領域】 本發明有關諸如圓規和分規之類的帶有針的製圖用具 中之針蓋，是爲確保使用安全性而設置的。例如當圓規不 使用時，可將從針腳下端伸出的圓心針覆蓋，藉此消除圓 心針不慎刺到手之類的刺傷等危險。 【先前技術】 過去對於圓規等製圖用具，爲防止發生由於針造成的 事故而採取了種種的對策，例如，在實開平3-62897號之日 本公報等中記載的帶有針蓋的圓規已眾所周知。 在實開平3-62897號之日本公報中記載的圓規具有以下 結構：在帶有伸出的圓心針的針腳的該圓心針的周圍設計 了一個針蓋，該針蓋可在人爲的強制力作用下在與該圓心 針的軸平行的上下方向自如地滑動，並且在該針蓋的內表 面及前述針腳的表面上還分別設有長槽以及小凸起，該長 槽和小凸起具有分離阻止功能和導引功能，其中前述分離 阻止功能防止針蓋的脫落，前述導引功能將針蓋導引至覆 蓋圓心針的下死點位置以及使圓心露出針的上死點位置。 換句話說，當圓規在不使用時，使小凸起滑動到其與 長槽下端相卡合的針蓋的下死點位置，圓心針被覆蓋，從 而防止刺傷之類的事故。另一方面，在使用圓規時，使小 凸起滑動到其與長槽上端相卡合的針蓋的上死點位置，圓 心針可從針蓋下端的出入口伸出。 【發明內容】 1231791 然而，上述習知圓規之所以能在圓心覆蓋針的下死點 處和圓心露出針的上死點處將針蓋分別定位，靠的是環抱 針腳的橫截面呈大致C字形的針蓋的內表面相對於針腳的 外表面的摩擦力。 這樣，在過去，必須加大針蓋對針腳的表面摩擦而產 生的摩擦力，因此針蓋的滑動不順。所以要使針蓋滑動， 往往需要用一隻手緊緊握住針蓋，用另一隻手緊緊握住針 腳’否則容易出現針蓋不能滑動至上、下死點位置之類的 操作困難的問題，尤其是對於小學生來說不僅針蓋難以滑 動，而且還存在由於注意力集中在推動針蓋的滑行上而帶 來手被伸出的針刺傷的危險。 而且，習知的圓規由於靠表面摩擦來實現針蓋在下、 上死點處的定位，加之使針蓋將針覆蓋和使針露出的操作 ，如前述的那樣，只是與針的軸平行的上下方向的滑動， 所以在針蓋的前端部（針尖覆蓋部）必須設計出從仰視圖來看 呈大致U字形的供針出入的出入口。 所以當圓規不慎落地等時，由於衝擊導致針蓋鬆動， 致使本應收容在針蓋內的針從出入口伸出，伸手去撿時又 沒有注意到針已伸出，存在被刺傷等的危險，因此有必要 硏製使用時的安全對策。 本發明是鑒於以往的情況而進行的，其目的在於提供 改進了安全對策和使用性能的圓規和分規等製圖用具，可 簡單地由單手使針蓋在覆蓋針的下死點和露出針的上死點 間移動；而且在下、上死點處針蓋能被卡止地保持；甚至 1231791 萬一出現不慎用具落地等情況時，也能確實防止針突然露 出。 爲達到以上目的，本發明針對圓規和分規之類的帶有 針的製圖用具，在帶有前述針的針腳、和可往針腳方向擺 動且可上下滑動的針蓋之間設有卡止部，該卡止部係交替 地並且卡脫自如地卡止於：針蓋的將針覆蓋的下死點位置 和針蓋的使針露出的上死點位置這上下兩點。 另外，本發明針對圓規和分規之類的帶有針的製圖用 具，在帶有前述針的針腳、和覆蓋針的橫截面呈大致C字 形的針蓋之間設有保持部，該保持部將針蓋以其可往針腳 方向擺動且可上下滑動之方式保持，並且，在上述針腳和 針蓋之間設有下、上死點用卡止部，該下死點用卡止部的 作用在於：當針蓋滑動前進至覆蓋針的下死點位置後、按 壓針蓋的擺動中心的前半部側使其擺動時，用來將針蓋卡 脫自如地卡止；前述上死點用卡止部的作用在於：當按壓 針蓋的擺動中心的後半部側使其擺動後，使針蓋滑動後退 至露出針的上死點位置時，用來將針蓋卡脫自如地卡止。 此外，上述下、上死點用的兩卡止部，係由相互嵌合 的凸部和凹部構成，透過其中一方設在針蓋側，另一方設 在針腳側之針蓋的下死點位置和上死點位置，可使針蓋在 覆蓋針的下死點和露出針的上死點處，以凸部和凹部之卡 止鎖住狀態被牢固地保持。 再者，上述針蓋係由具有彈性與適宜剛性的材料製成 ，其橫截面形成大致的C字形，在擺動中心的前半部側的 1231791 兩側邊部設有下、上死點用卡止部，並且從該前半部側的 下端開始設有將兩側邊部左右分開的狹縫，目的在於確保 前述卡止部的卡止力的可靠性和長期的穩定性（提高耐久性) 【實施方式】 本發明的實用例將參閱圖予以說明。 作爲應用本發明的帶有針的製圖用具的一個典型例， 圖1顯示了一種圓規之前視圖，其由如下所周知的構件構 成：帶有針1的針腳2;書寫腳3 ;開合該針腳2和書寫腳 3的圓規頭部4 ;裝在該圓規頭部4的上表面中央部位的握 把5，並且在針腳2的伸出有針1的下端設有既能擺動又能 上下滑動的針蓋6。 另外，作爲圓規可以指多種類型的圓規，比如圖中所 示的書寫腳3上裝備有自動鉛筆3-1的自動鉛筆型、備有 用於安裝鉛筆的鉛筆保持件的鉛筆型、和備有用於安裝鉛 筆芯的鉛筆芯保持件的鉛筆芯型等。 在從伸出有針1的下端至針蓋6的上下滑動範圍內相 對應的針腳2的下端部分的橫截面形成如圖2所示的由寬 部2-1和窄部2-2構成的大致凸起的形狀，在寬部2-1的上 方部分的兩側面上，設有將針蓋6以其可上下滑動並且可 往針腳2方向擺動之方式保持的保持部7，同時在窄部2-2 下端的兩側面上設有針蓋滑行的下、上死點用卡止部8、9 〇 針蓋6依靠往針腳2方向擺動和上下滑動的雙重操作 1231791 ，來完成覆蓋針1和使其伸出的動作（參照圖4(a)、（c))，該 針蓋6選用具有良好彈性（復原能力）和適宜剛性（耐摩損性 和保持彈性的耐久強度）的合成樹脂材料，例如聚丙烯、聚 碳酸酯等熱塑性樹脂材料等成型材料成型，在指定的長度 範圍內的橫截面以大致的C字形形成，其前端（下端）具有封 閉型的針尖覆蓋部6-1。 透過使與針尖覆蓋部6-1相連接的針蓋6的前半部側 的兩側邊部6-2的厚度向內側增厚地形成，在該前端側內 部設有供針腳2的薄部2_2嵌入並滑行的窄槽10，該窄槽 10的內側尺寸相當於針腳2的窄部2-2的寬度，在該窄槽 10的兩內表面的下、上兩處設有下、上死點用卡止部8、9 〇 針蓋6的兩側邊部6-2的開放狀邊緣以在側視圖中以 與針尖覆蓋部6-1相連接的前端開始，沿縱向向後端延伸 的部分呈近似a字形地形成，然後朝向上邊部6-3的後端 設置呈大致彎曲狀的彎曲緣部6-21，在位於針蓋6的長度 方向中央部位的後方，連接前述彎曲緣部6-21和a字形緣 部6-20的夾角部位的兩側邊部6-2的內表面設有保持部7 ，該保持部7將針蓋6以其可上下滑動並且可往針腳2方 向擺動之方式保持。 圖中的11部分是一個狹縫，如圖所示的那樣，該狹縫 從針蓋6的具有針尖覆蓋部6-1的前端起，沿上邊部6-3的 橫向中央線設置於針蓋6的前半部側，透過設置此狹縫11 ，確保後面將要說明的針蓋6的下、上死點用卡止部8、9 1231791 的凹部8-1、9-1和凸部8-2、9-2之間的卡脫自如的卡止力 具有可靠性和長期的穩定性（提高耐久性）。 圖中的12表示設置於針蓋6的上邊部6-3的防滑部， 在將拇指的指腹置於該防滑部12，然後按壓針蓋6的前半 部側和後半部側以使其以擺動中心P爲支點往針腳2方向 擺動，或者使其上下滑動時，該防滑部12能夠使上述操作 順利進行（參照圖4)。 保持部7的作用是在保證針蓋6不從針腳2脫落的狀 態下，將針蓋6以其可上下滑動並且可往針腳2方向擺動 之方式保持，該保持部7由長槽7-1和凸部7-2構成，其中 前述長槽7-1設於針腳2的寬部2-1的後方部位，其長度對 應於針蓋6的上下滑動範圍；前述凸部7-2設於針蓋6的前 半部和後半部之間的前述的兩側邊部6-2的內表面，其外 徑和高度與長槽7-1的寬度和深度相對應，針蓋6的前半 部和後半部受壓後能以該凸部7-2爲中心往針腳2方向擺 動。 也就是說，當使針蓋6滑動前進至凸部7-2被卡止於 長槽7-1下端的下死點位置後，按壓針蓋6的前半部側而 使其以凸部7-2爲擺動中心P擺動，可將伸出針腳2下端 的針1覆蓋，並且，在這種狀態下，按壓針蓋6的擺動中 心P點的後半部側使其擺動，可使針1露出，並可使針蓋6 退至使針1完全露出的上死點位置。 下死點用卡止部8具有以下功能：在針蓋6被推至其 覆蓋針1的下死點位置後，按壓前述擺動中心P的前半部 11 1231791 側而使其擺動，使卡止部相互嵌合並卡止，從而牢固地鎖 住保持針蓋6。 該卡止部8由凹部8-1和凸部8-2構成，其中凹部8-1 設於針腳2的窄部2-2的前端的兩側面；凸部8-2設於針蓋 6上的窄槽10的後端的內側兩表面。當針蓋6從上死點位 置被向前推出後，通過按壓針蓋6的位於擺動中心P(凸部 7-2)的前半部側（上邊部6-3的前端側）而使其往針腳2方向 擺動，使凸部8-2與凹部8-1相互嵌合並卡止，將覆蓋針1 的針蓋6鎖住保持（圖4(c)的狀態）。 此時，透過按壓處於從針腳2上浮起而與其分離狀態 的針蓋6的後半部側（上邊部6-3的後端側）而使其往針腳2 方向擺動，可解除該卡止狀態（圖4(b)的狀態）。 上死點用卡止部9具有以下功能：在按壓前述擺動中 心P的後半部側使其擺動而解除下死點用卡止部8對於針 蓋6的卡止狀態後、將針蓋滑動後退至針1完全露出的上 死點位置時，使其互相嵌合並卡止，從而將針1牢固地鎖 住保持在上死點位置。 卡止部9由凹部9-1和凸部9-2構成，其中凹部9-1設 於針腳2的窄部2-2的前端的兩側面；凸部9-2設於針蓋6 上的窄槽10的前端的兩內表面，透過將針蓋6從下死點位 置滑動後退，使凸部9-2與凹部9-1相互嵌合並卡止而將針 蓋6鎖住保持於上死點位置（圖4(a)的狀態）。 此時，透過使針蓋6從上死點位置滑動前進至下死點 位置，可解除該卡止狀態（圖4(a)的由實線位置滑動至2點 12 1231791 鏈線位置的狀態）。。 下面，簡單地說明具有前述結構的本實施例中詳細說 明的圓規的使用方法。 圓規使用完畢後，用食指、中指和無名指將針腳2抓 住，將拇指的指腹置於針蓋6的上邊部6-3的防滑部12(圖 4(a)的由實線位置滑動至2點鏈線位置的狀態）。然後在該 狀態下將針蓋6滑動前進至下死點位置（圖4(a)的實線所示 狀態），再以擺動中心P(凸部7-2)爲支點，按壓針蓋6的前 半部側而使其往針腳2方向擺動（圖4(b)的2點鏈線的狀態) 〇 這樣，針蓋6的下死點用卡止部8的凸部8-2嵌入針腳 2的下死點用卡止部8的凹部8-1並卡止，藉此覆蓋針1的 針蓋6由於凸部8-2被卡止在凹部8-1裏而被牢固地保持。 另一方面，在使用該圓規時，如前述的那樣，握住針 腳2，將拇指的指腹置於從針腳2上浮起的針蓋6的上邊部 6-3的後半部側，使其以擺動中心P(凸部7-2)爲支點往針腳 2方向擺動（從圖4(c)的狀態變爲（b)的狀態）。 這樣，針蓋6的下死點用卡止部8的凸部8-2從針腳2 的下死點用卡止部8的凹部8-1中脫出，從而解除針蓋6的 該卡止狀態（圖4(b)的由2點鏈線狀態變爲實線狀態）。 接下來，在將拇指置於針蓋6的上邊部6-3的狀態下 使將針蓋6推至上死點位置（從圖4(b)的狀態變爲（a)的狀態） 〇 這樣，針蓋6的上死點用卡止部9的凸部9-2嵌入針腳 13 1231791 2的上死點用卡止部9的凹部9-1並卡止，藉此，針蓋6由 於凸部8-2被卡止在凹部8-1裏而被牢固地保持，並且將針 1在針露出的使用狀態下保持。 另外，作爲參考，本發明也可設計成圖5所示的那樣 ;在針蓋6前端的針尖覆蓋部6-1上開設一個大致呈倒置 的U形的視窗13，在這種情況下，最好使其這樣形成：當 針蓋6被推至使針1伸出的上死點位置時，窗口 13可以同 針蓋6的窄槽10 —樣地與針腳2的窄部2-2相嵌合並且使 該窄部2-2的下端面與帶有針1的針腳2的下端面相平齊。 與上述實施例中詳細說明的圓規不同，圖6顯示了本 發明的製圖用具在分規中的應用例。由於其基本結構和前 述結構相同，並且同樣的構件使用了相同的符號，在此不 再詳述。 將本發明的帶有針的圓規或分規之類的製圖用具以前 述構造形成，可產生以下效果：本發明中，由於將伸出針 腳下端的針覆蓋和露出的操作是透過以擺動中心P爲支點 往針腳方向的擺動和往上下的滑動這樣的雙重結構來完成 的，因而不必像過去那樣一定要在針蓋前端部的針尖覆蓋 部上設置供針出入的出入口。 即使用具不慎落地等時的衝擊使針蓋產生後退等運動 ，也不存在針從針蓋中突然露出的危險。 另外，在覆蓋針的針蓋的下死點位置和使針露出的上 死點位置，針蓋是透過這樣的結構對針腳進行保持的：使 針蓋和針腳在下、上死點位置處相互嵌合地在其間設有上 1231791 、下死點用卡止機構，因而針蓋對針腳的環抱狀態自然並 且良好。 換言之，由於本實施例不採用習知方法中造成上下滑 動不順之摩擦面結構·，即，不採用靠摩擦力來將針蓋保持 於其上、下死點位置之方法，而是將針蓋組裝到針腳上， 所以無須大的力氣，單手操作就可使針蓋滑至將針覆蓋的 下死點位置和使針露出的下死點位置。 由此可見，本發明能夠提高圓規或分規之類的帶有針 的製圖用具的安全性和使用性，成年人自不必說，就連小 學生等兒童也能簡單且容易地使針蓋滑動而將針覆蓋或使 其露出，而且即使發生用具不慎落地等的意外情況，也可 確保針不會從針蓋中突然露出。 【圖式簡單說明】 (一）圖式部分 圖1顯示本發明的製圖用具的一個實施例的圓規前視 圖·· U)表示針露出的使用狀態；（b)表示針被覆蓋的收容狀 態。 圖2顯示重要部位的放大的剖面圖： U)表示圖1所示的（a)-(a)的剖面圖； (b)表示圖1所示的（b)-(b)的剖面圖。 圖3顯示針蓋單元的仰視圖。 圖4用局部的放大的縱剖面圖說明針蓋的運動： (a)表示針蓋從露出針的上死點位置滑動前進的情況； 15 1231791 (b)表示針蓋滑動至覆蓋針的下死點位置後，按壓其後 半部側使其以擺動中心爲支點往針腳方向擺動的情況； (C)表示針被覆蓋時的情況。 圖5顯示另一實施例，其針蓋前端的覆蓋針的部位開 設有小窗： (a) 表示針蓋從露出針的上死點位置滑動前進的情況； (b) 表不（a)圖中（b)-(b)的剖面放大圖， (c) 表示針蓋滑動至覆蓋針的下死點位置後，按壓其後 半部側而使其以擺動中心爲支點往針腳方向擺動，從而將 針覆蓋的情況。 圖6顯示應用本發明的製圖用具的另一實施例中的分 規的前視圖。 (二）元件代表符號 1 針 2 針腳 3 書寫腳 4 圓規頭部 5 握把 6 針蓋 6-1針尖覆蓋部6-2兩側邊部6_3上邊部 7 保持部 7-1長槽7-2凸部 8 下、上死點用卡止部8-1凹部8-2凸部 9 卡止部 9-1凹部9-2凸部 161231791 发明 Description of the invention [Technical field to which the invention belongs] The present invention relates to a needle cover in a drawing tool with a needle, such as a compass and a division gauge, and is provided to ensure safety in use. For example, when the compass is not in use, it can be covered by the center pin protruding from the lower end of the pin, thereby eliminating the danger of stabbing, such as accidentally sticking the center pin to your hand. [Prior art] In the past, various countermeasures have been taken for drawing tools such as compasses to prevent accidents caused by needles. For example, the compasses with needle caps described in Japanese Gazette No. 3-62897 and the like are well known. . The compass described in the Japanese Gazette No. 3-62897 has the following structure: a needle cover is designed around the center needle with a protruding center needle, and the needle cover can be under artificial force Under the action, it slides freely in the up-and-down direction parallel to the axis of the circular center pin, and a long groove and a small protrusion are also provided on the inner surface of the needle cover and the surface of the stitch, respectively. The long groove and small protrusion have A separation prevention function and a guide function, wherein the separation prevention function prevents the needle cap from falling off, and the foregoing guide function guides the needle cap to a position where the bottom dead center of the center needle is covered and where the center of the needle is exposed from the top dead center of the needle. In other words, when the compass is not in use, the small protrusion is slid to the bottom dead center position of the needle cover that engages with the lower end of the long groove, and the center needle is covered to prevent accidents such as stabbing. On the other hand, when using a compass, slide the small protrusion to the top dead center position of the needle cover that engages with the upper end of the long groove, and the center needle can protrude from the entrance and exit of the lower end of the needle cover. [Summary of the Invention] 1231791 However, the reason why the above-mentioned conventional compasses can respectively position the needle caps at the center of the bottom dead point of the needle and where the center of the needle exposes the top dead point of the needle is that the cross section of the embracing pins is roughly C-shaped. Friction of the inner surface of the needle cap relative to the outer surface of the stitch. Thus, in the past, it was necessary to increase the frictional force generated by the needle cap rubbing against the surface of the stitches, so the sliding of the needle cap was not smooth. Therefore, to make the needle cover slide, it is often necessary to hold the needle cover tightly with one hand and hold the needle tightly with the other hand, otherwise it is easy to cause problems such as the needle cover not sliding to the upper and lower dead points. Especially for elementary school students, not only the needle cover is difficult to slide, but also the danger of needle sticking out of the hand due to the focus on pushing the needle cover to slide. Moreover, the conventional compasses rely on surface friction to realize the positioning of the needle cap at the bottom and top dead points, and the operations of covering the needle with the needle cap and exposing the needle, as described above, are only up and down parallel to the axis of the needle. Sliding in the direction, the front end portion (needle tip covering portion) of the needle cover must be designed with a substantially U-shaped entrance and exit for needle entry and exit from the bottom view. Therefore, when the compass is accidentally dropped on the ground, the needle cap is loose due to the impact, which causes the needle that should be contained in the needle cap to protrude from the entrance and exit. When you reach out to pick it up, you do not notice that the needle has extended, and there is a danger of stabbing, etc. Therefore, it is necessary to control the safety measures during use. The present invention has been made in view of the past situation, and an object thereof is to provide a drawing tool such as a compass and a division rule, which improves safety measures and usability, and the needle cap can be simply covered by one hand with the lower dead point of the needle and exposed. It can move between the top dead center; and the needle cover can be locked at the bottom and top dead center; even in the case of accidental landing of equipment, it can definitely prevent the needle from suddenly exposing. In order to achieve the above object, the present invention is directed to drawing tools with needles, such as compasses and dividers, provided with a locking portion between a pin with the aforementioned needle and a needle cover that can swing in the direction of the needle and can slide up and down. The locking portions are alternately and freely locked at two upper and lower points: the bottom dead center position of the needle cover covering the needle and the top dead center position of the needle cover exposing the needle. In addition, the present invention is directed to drawing tools with needles such as compasses and dividers. A holding portion is provided between the needle with the aforementioned needle and a needle cover having a substantially C-shaped cross section covering the needle. The needle cover is held in such a way that it can swing in the direction of the stitches and can slide up and down, and a locking part for the lower and upper dead point is provided between the stitch and the needle cover, and the role of the locking part for the lower dead point is to : When the needle cover slides to the bottom dead center position of the needle and presses the front half of the swing center of the needle cover to make it swing, it is used to freely lock the needle cover; the above top dead center is locked with The function of the portion is to lock the needle cover freely when the rear half of the swing center of the needle cover is pressed to swing, and then the needle cover is slid back to the top dead center position where the needle is exposed. In addition, the two locking portions for the lower and upper dead points are composed of convex and concave portions that are fitted to each other. One of the locking portions is provided on the needle cover side and the other is provided on the needle cover. With the top dead center position, the needle cover can be firmly held at the bottom dead center where the needle is covered and the top dead center where the needle is exposed. In addition, the needle cover is made of a material with elasticity and suitable rigidity, and its cross section is formed into a substantially C-shape. The sides of the front half of the center of the swing are 1231791, and the bottom and top dead points are locked with locks. And from the lower end of the front half side, slits are formed to separate the sides of the two sides from left to right, the purpose is to ensure the reliability of the locking force of the aforementioned locking portion and long-term stability (improved durability) [Implementation Mode] A practical example of the present invention will be described with reference to the drawings. As a typical example of a drawing tool with a needle to which the present invention is applied, FIG. 1 shows a front view of a compass, which is composed of a well-known member: a pin 2 with a needle 1; a writing pin 3; and opening and closing the pin 2 and compass head 4 of writing foot 3; a grip 5 mounted on the center of the upper surface of the compass head 4, and a lower end of the needle 1 protruding from the needle 2 is provided with a swinging and sliding up and down Needle cover 6. In addition, the compass can refer to various types of compasses, such as a mechanical pencil type equipped with a mechanical pencil 3-1 on the writing foot 3 shown in the figure, a pencil type provided with a pencil holder for mounting a pencil, and The lead type of the lead holder for the lead, etc. The cross section of the lower end portion of the corresponding pin 2 in the range of sliding up and down from the lower end of the needle 1 to the needle cover 6 is formed by a wide portion 2-1 and a narrow portion 2-2 as shown in FIG. 2. The generally convex shape is provided on both sides of the upper part of the wide part 2-1 with holding parts 7 for holding the needle cover 6 in such a manner that it can slide up and down and swing in the direction of the pin 2. 2-2 Both sides of the lower end are provided with needle cap sliding bottom and top dead point locking portions 8, 90. The needle cap 6 relies on the double operation of swinging and sliding up and down in the direction of pin 2, 1231791 to cover the needle 1 and To make it extend (refer to Figure 4 (a), (c)), the needle cap 6 is made of synthetic resin material with good elasticity (recovery ability) and suitable rigidity (abrasion resistance and durable strength to maintain elasticity). For example, molding materials such as thermoplastic resin materials such as polypropylene and polycarbonate are molded, and the cross section within a specified length range is formed in a substantially C-shape, and the front end (lower end) has a closed needle tip covering portion 6-1. The side portions 6-2 on the front half side of the needle cover 6 connected to the needle tip covering portion 6-1 are formed thicker inward, and a thin portion 2_2 for the needle 2 is provided inside the front end side. The narrow groove 10 inserted and sliding, the inside dimension of the narrow groove 10 is equivalent to the width of the narrow part 2-2 of the pin 2, and the bottom and upper dead points are provided at the lower and upper two places of the two inner surfaces of the narrow groove 10. With the locking portions 8 and 90, the open edges of both sides 6-2 of the needle cover 6 start at the front end connected to the needle tip covering portion 6-1 in a side view, and the portion extending in the longitudinal direction toward the rear end is shown. It is formed in an approximately a-shape, and then a curved edge portion 6-21 having a substantially curved shape is provided toward the rear end of the upper edge portion 6-3. The curved edge portion 6 is located behind the central portion of the needle cap 6 in the longitudinal direction, and connects the curved edge portion 6- The inner surface of both sides 6-2 of the angled portion of the 21 and a-shaped edge portions 6-20 is provided with a holding portion 7 which can slide the needle cover 6 up and down and swing toward the pin 2 Way to keep. Part 11 in the figure is a slit. As shown in the figure, the slit is provided on the needle cap 6 from the front end of the needle cap 6 with the needle tip covering portion 6-1 and along the lateral centerline of the upper portion 6-3. This slit 11 is provided on the front half side of 6 to secure the recessed portions 8-1, 9-1 and convex portions 8-2 of the lower and top dead center locking portions 8 and 9 1231791 of the needle cover 6 to be described later. The free-running locking force between 9 and 9-2 has reliability and long-term stability (improved durability). Reference numeral 12 in the figure indicates a non-slip portion provided on the upper side portion 6-3 of the needle cover 6. After the thumb abdomen is placed on the non-slip portion 12, the front half side and the rear half side of the needle cover 6 are pressed so that When the swing center P is a fulcrum swinging in the direction of the stitch 2 or it is slid up and down, the non-slip portion 12 can smoothly perform the above operation (see FIG. 4). The role of the holding portion 7 is to keep the needle cover 6 in a state that the needle cover 6 can slide up and down and swing in the direction of the needle 2 while ensuring that the needle cover 6 does not fall off from the pin 2. The holding portion 7 is formed by a long groove 7-1. And the convex part 7-2, wherein the long groove 7-1 is provided at the rear part of the wide part 2-1 of the stitch 2, and its length corresponds to the vertical sliding range of the needle cover 6; the convex part 7-2 is provided in the needle The outer surface and height of the inner surface of the aforementioned two-side edge portion 6-2 between the front half and the rear half of the cover 6 correspond to the width and depth of the long groove 7-1. The front half and the rear half of the needle cover 6 After the part is pressed, the convex part 7-2 can be swung in the direction of the stitch 2 with the center. That is, after the needle cover 6 is slid forward to the bottom dead center position of the convex portion 7-2 being locked at the lower end of the long groove 7-1, the front half side of the needle cover 6 is pressed to make the convex portion 7- 2 is the swing center P, which can cover the needle 1 protruding from the lower end of the pin 2 and, in this state, press the rear half of the swing center P of the needle cover 6 to swing, so that the needle 1 can be exposed, And the needle cover 6 can be retracted to the top dead center position where the needle 1 is fully exposed. The bottom dead center locking portion 8 has the following function: After the needle cover 6 is pushed to the bottom dead center position covering the needle 1, the front half 11 1231791 side of the aforementioned swing center P is swung to make the locking portion They are fitted to each other and locked, so that the holding needle cover 6 is firmly locked. The locking portion 8 is composed of a concave portion 8-1 and a convex portion 8-2. The concave portion 8-1 is provided on both sides of the front end of the narrow portion 2-2 of the pin 2. The convex portion 8-2 is provided on the needle cover 6. The narrow groove 10 has two inner surfaces at the rear end. After the needle cover 6 is pushed forward from the top dead center position, the needle cover 6 is pushed toward the front half side (the front end side of the upper portion 6-3) of the swing center P (the convex portion 7-2). The pin 2 is swung in the direction so that the convex portion 8-2 and the concave portion 8-1 are fitted and locked with each other, and the needle cover 6 covering the needle 1 is locked and held (the state of FIG. 4 (c)). At this time, the latched state can be released by pressing the rear half side of the needle cover 6 (the rear end side of the upper portion 6-3) which is floating and separated from the pin 2 to the direction of the pin 2 ( Figure 4 (b)). The top dead center locking portion 9 has a function of pressing the rear half side of the swing center P to swing to release the locking state of the bottom dead center locking portion 8 to the needle cover 6, and sliding the needle cover back. When the top dead center position of the needle 1 is completely exposed, they are fitted and locked with each other, so that the needle 1 is firmly locked and held at the top dead center position. The locking portion 9 is composed of a concave portion 9-1 and a convex portion 9-2. The concave portion 9-1 is provided on both sides of the front end of the narrow portion 2-2 of the pin 2. The convex portion 9-2 is provided on the needle cover 6. The two inner surfaces of the front end of the narrow slot 10 slide the needle cover 6 back from the bottom dead center position, so that the convex portion 9-2 and the concave portion 9-1 are fitted and locked with each other, and the needle cover 6 is locked and held at the top. Point position (state of Fig. 4 (a)). At this time, by sliding the needle cover 6 from the top dead center position to the bottom dead center position, the locked state can be released (the state of sliding from the solid line position to the chain point position at 12: 1231791 in Figure 4 (a)). . . Hereinafter, a method of using the compass detailed in this embodiment having the aforementioned structure will be briefly described. After using the compass, grasp pin 2 with your index finger, middle finger, and ring finger, and place the abdomen of your thumb on the anti-slip part 12 of the upper part 6-3 of the needle cover 6 (slide from the solid line position to 2 point chain line position). Then in this state, slide the needle cover 6 to the bottom dead center position (the state shown by the solid line in FIG. 4 (a)), and then use the swing center P (the convex portion 7-2) as the fulcrum to press the needle cover 6 The front half is swung in the direction of pin 2 (the state of the two-point chain line in FIG. 4 (b)). In this way, the convex portion 8-2 of the lower dead point locking portion 8 of the needle cover 6 is fitted into the pin 2 The concave portion 8-1 of the bottom dead center locking portion 8 is locked and locked, whereby the needle cover 6 covering the needle 1 is firmly held by the convex portion 8-2 being locked in the concave portion 8-1. On the other hand, when using the compass, as described above, hold pin 2 and place the thumb's abdomen on the rear half of the upper part 6-3 of the needle cap 6 floating from pin 2 so that The swing center P (the convex portion 7-2) is a fulcrum swinging in the direction of the pin 2 (from the state of FIG. 4 (c) to the state of (b)). In this way, the convex portion 8-2 of the bottom dead center locking portion 8 of the needle cover 6 is released from the concave portion 8-1 of the bottom dead center locking portion 8 of the pin 2, and the locking of the needle cover 6 is released. State (from the 2-point chain line state to the solid line state in Figure 4 (b)). Next, with the thumb on the upper part 6-3 of the needle cover 6, the needle cover 6 is pushed to the top dead center position (from the state of FIG. 4 (b) to the state of (a)). Thus, The convex portion 9-2 of the top dead center locking portion 9 of the needle cover 6 is fitted into the concave portion 9-1 of the top dead center locking portion 9 of the pin 13 1231791 2 and locked, whereby the needle cover 6 is caused by the convex portion 8-2 is locked in the recessed portion 8-1 and held firmly, and the needle 1 is held in the use state where the needle is exposed. In addition, for reference, the present invention can also be designed as shown in FIG. 5; a substantially inverted U-shaped window 13 is opened on the needle tip covering portion 6-1 at the front end of the needle cover 6. In this case, the most So that it is formed as follows: When the needle cover 6 is pushed to the top dead center position where the needle 1 is extended, the window 13 can be fitted with the narrow groove 10 of the needle cover 6 in the same way as the narrow part 2-2 of the needle 2 Close and make the lower end surface of the narrow part 2-2 flush with the lower end surface of the stitch 2 with the needle 1. Unlike the compasses described in detail in the above embodiment, Fig. 6 shows an example of application of the drawing tool of the present invention to the divisional rule. Since its basic structure is the same as the aforementioned structure, and the same components use the same symbols, they will not be described in detail here. Forming a drawing tool such as a compass with a needle or a divider according to the present invention with the aforementioned structure can produce the following effects: In the present invention, since the operation of covering and exposing the needle protruding from the lower end of the stitch is performed by using the swing center P as The fulcrum swings in the direction of the stitches and slides up and down to complete the double structure. Therefore, it is not necessary to provide an entrance for the needle to enter and exit the needle tip covering part at the front end of the needle cover as in the past. There is no danger that the needle may suddenly come out of the needle cover even if the impact caused by accidental dropping of the device causes the needle cover to move backwards. In addition, at the bottom dead center position of the needle cover covering the needle and the top dead center position at which the needle is exposed, the needle cover holds the stitches through a structure such that the needle cover and the needles are embedded with each other at the bottom and top dead center positions. The ground is provided with a locking mechanism for the upper 1231791 and the lower dead point in between, so the state of the needle cap embracing the pins is natural and good. In other words, since the present embodiment does not use the friction surface structure that causes the vertical sliding irregularity in the conventional method, that is, does not adopt the method of holding the needle cover at its upper and lower dead point positions by friction, but the needle cover Assembled on the pins, so no great effort is needed, and the needle cover can be slid to the bottom dead center position where the needle is covered and the bottom dead center position where the needle is exposed with one hand operation. It can be seen that the present invention can improve the safety and usability of drawing tools with needles, such as compasses and dividers. Needless to say, adults can easily and easily slide the needle caps even children such as elementary school students. Covering or exposing the needle, and ensuring that the needle does not suddenly come out of the needle cover, even if accidents such as accidental dropping of the appliance occur. [Brief description of the drawings] (I) Schematic part Fig. 1 shows a compass front view of an embodiment of the drawing tool of the present invention. U) shows the use state where the needle is exposed; (b) shows the storage state where the needle is covered. FIG. 2 shows an enlarged sectional view of an important part: U) shows a sectional view of (a)-(a) shown in FIG. 1; (b) shows a sectional view of (b)-(b) shown in FIG. 1. Figure 3 shows a bottom view of the needle cover unit. Figure 4 illustrates the movement of the needle cap with a partially enlarged longitudinal sectional view: (a) shows the state where the needle cap slides from the top dead center position where the needle is exposed; 15 1231791 (b) shows the needle cap slides to cover the bottom of the needle After the point position is pressed, the rear half side is pressed to swing toward the stitches with the swing center as a fulcrum; (C) shows the situation when the needles are covered. Fig. 5 shows another embodiment, a small window is provided on the front end of the needle cover covering the needle: (a) shows the situation where the needle cover slides forward from the top dead center position exposing the needle; (b) shows (a) the figure (B)-(b) is an enlarged sectional view. (C) shows that the needle cover slides to the bottom dead center position of the needle, and then presses the rear half of the needle cover to swing it toward the stitches with the swing center as the fulcrum. Needle-covered condition. Fig. 6 shows a front view of a division in another embodiment of a drawing implement to which the present invention is applied. (II) Symbols for components 1 Pin 2 Pin 3 Writing pin 4 Compass head 5 Grip 6 Needle cover 6-1 Needle tip covering part 6-2 Side parts 6_3 Upper part 7 Holding part 7-1 Long groove 7-2 Convex part 8 Locking part for lower and top dead center 8-1 Concave part 8-2 Convex part 9 Locking part 9-1 Concave part 9-2 Convex part 16