機械設計課程設計-二級斜齒圓柱齒輪減速器設計F=3800 V=1.8 D=320

1、機械設計課程設計任務書全套圖紙加V信153893706或扣 3346389411學號 姓名 設計題號 設計題目:皮帶運輸機傳動裝置 機械運動簡圖:1- 電動機 2聯軸器 3-圓柱齒輪減速器 4-運輸帶 5滾筒運輸帶牽引力F（牛頓）3800每日工作時數t（小時）8運輸帶速度V（米/秒）1.8傳送帶工件年限（年）15滾筒直徑D（毫米）320注：傳送帶不逆轉，工作載荷平穩(wěn)，允許輸送帶速度誤差為±5。設計工作量：一 繪制減速器裝配圖1張二 繪制減速器零件圖2張，三 編寫設計說明書份一 傳動方案分析該方案的優(yōu)缺點：1-電動機 2聯軸器 3-圓柱齒輪減速器 4-運輸帶 5滾筒 該工作機運動較平穩(wěn)

2、，并且該工作機功率不是很大、載荷變化不大，采用二級圓柱齒輪減速器這種簡單傳動結構，能使傳動效率高，結構緊湊。采用閉式齒輪傳動能有效防塵，保證潤齒輪潤滑的良好。二級圓柱齒輪減速，是減速器中應用最廣泛的一種。齒輪相對于軸承不對稱，要求軸具有較大的剛度。高速級齒輪常布置在遠離扭矩輸入端的一邊，以減小因彎曲變形所引起的載荷沿齒寬分布不均現象。 總體來講，該傳動方案滿足工作機的性能要求，適應工作條件、工作可靠，此外還結構簡單、尺寸緊湊、成本低傳動效率高。二.原動機選擇與計算（Y系列三相交流異步電動機）已知傳送帶工作拉力F=3800N，輸送帶轂輪轉速 V1.8m/s，鼓輪直徑D=320mm=0.32m。2

3、.1類型：Y系列三相異步電動機；2.2功率選擇：工作帶所需轉速：工作機所需輸入功率：;電機所需功率：;其中，為滾筒工作效率，0.96 聯軸器效率，0.99 為圓柱齒輪效率，0.97 為軸承效率，0.995所以 7.84 KW2.3電機轉速選擇輸送機工作轉速電機同步轉速選：1000；2.4電機型號確定所以查表選電機型號為：Y160L-6 電機參數：額定功率：11Kw滿載轉速：970三. 傳動裝置的運動和動力參數的選擇和計算3.1 總傳動比和各級傳動比分配： 其中：為高速級傳動比，為低速級傳動比，且，?。?；3.2 各軸傳動裝置的運動和動力參數1）高速軸：； ；2） 中間軸：； ；3） 低速軸：；

4、；四 高速級齒輪傳動設計(斜齒傳動）4.1選精度等級、材料及齒數1為提高傳動平穩(wěn)性及強度，選用斜齒圓柱齒輪小齒輪材料：45鋼調質 HBS1=280接觸疲勞強度極限MPa （由1P207圖10-21d）彎曲疲勞強度極限 Mpa （由1P204圖10-20c）大齒輪材料：45號鋼正火 HBS2=240接觸疲勞強度極限 MPa （由1P206圖10-21c） 彎曲疲勞強度極限 Mpa （由1P204圖10-20b）3精度等級選用7級精度4初選小齒輪齒數24大齒輪齒數Z2 = Z1= 24×3.6=86取865初選螺旋角4.2 按齒面接觸強度設計 計算公式： mm （由1P216式10-21

5、） 1 確定公式內的各計算參數數值初選載荷系數小齒輪傳遞的轉矩 N·mm齒寬系數 （由1P201表10-7） 材料的彈性影響系數 Mpa1/2 （由1P198表10-6）區(qū)域系數 （由1P215圖10-30）， （由1P214圖10-26） 應力循環(huán)次數接觸疲勞壽命系數 （由1P203圖10-19）接觸疲勞許用應力取安全系數.0 取 2 計算（1）試算小齒輪分度圓直徑=58.9mm（2）計算圓周速度 m/s（3）計算齒寬b及模數mnt mmb/h=10.994計算縱向重合度 =2.0933（5） 計算載荷系數 使用系數 <由1 P190表10-2> 根據電動機驅動得 動載

6、系數 <由1 P192表10-8> 根據v=1.43m/s、 7級精度1.1 按齒面接觸強度計算時的齒向載荷分布系數 <由1P194表10-4> 根據小齒輪相對支承為非對稱布置、7級精度、=1.0、 mm，得 =1.42 按齒根彎曲強度計算時的齒向載荷分布系數<由1P195圖10-13> 根據b/h=10.99、 齒向載荷分配系數、<由1P193表10-3> 假設，根據7級精度，軟齒面?zhèn)鲃?，?=2.73（6） 按實際的載荷系數修正所算得的分度圓直徑 <由1P200式(10-10a)> mm（7） 計算模數4.3按齒根彎曲強度設計 &

7、lt;由1P198式(10-5)>1 確定計算參數（1）計算載荷系數K （2）螺旋角影響系數 <由1P215圖10-28> 根據縱向重合系數，得0.92（3）彎曲疲勞系數KFN<由1P202圖10-18> 得 （4）計算彎曲疲勞許用應力 取彎曲疲勞安全系數S=1.2 <由1P202式(10-12)>得（5）計算當量齒數ZV取27取94（6）查取齒型系數YF 應力校正系數YS<由1P197表10-5> 得 （7）計算大小齒輪的 并加以比較比較<所以大齒輪的數值大，故取0.014269。2 計算=1.96mm取24.4 分析對比計算結果對

8、比計算結果，取=2.0已可滿足齒根彎曲強度。但為了同時滿足接觸疲勞強度，需按接觸疲勞強度算得的d170.43mm來計算應有的 取35 取126需滿足、互質4.5 幾何尺寸計算1 計算中心距阿a將a圓整為165mm2 按圓整后的中心距修正螺旋角3 計算大小齒輪的分度圓直徑d1、d2 71.74mm258.26mm 4計算齒寬度 B=mm 取B1=75mm，B270mm五 低速級齒輪傳動設計(斜齒傳動）5.1選精度等級、材料及齒數1為提高傳動平穩(wěn)性及強度，選用斜齒圓柱齒輪小齒輪材料：45鋼調質 HBS1=280接觸疲勞強度極限MPa （由1P207圖10-21d）彎曲疲勞強度極限 Mpa （由1P

9、204圖10-20c）大齒輪材料：45號鋼正火 HBS2=240接觸疲勞強度極限 MPa （由1P206圖10-21c） 彎曲疲勞強度極限 Mpa （由1P204圖10-20b）3精度等級選用7級精度4初選小齒輪齒數23大齒輪齒數Z2 = Z1= 23×2.51=57.66取585初選螺旋角5.2 按齒面接觸強度設計 計算公式： mm （由1P216式10-21） 3 確定公式內的各計算參數數值初選載荷系數小齒輪傳遞的轉矩 N·mm齒寬系數 （由1P201表10-7） 材料的彈性影響系數 Mpa1/2 （由1P198表10-6）區(qū)域系數 （由1P215圖10-30）， （由

10、1P214圖10-26） 應力循環(huán)次數接觸疲勞壽命系數 （由1P203圖10-19）接觸疲勞許用應力取安全系數.0 取 4 計算（1）試算小齒輪分度圓直徑=91.63mm（2）計算圓周速度 m/s（3）計算齒寬b及模數mnt mmb/h=10.544計算縱向重合度 =2.093（5） 計算載荷系數 使用系數 <由1 P190表10-2> 根據電動機驅動得 動載系數 <由1 P192表10-8> 根據v=1.29m/s、 7級精度1.1 按齒面接觸強度計算時的齒向載荷分布系數 <由1P194表10-4> 根據小齒輪相對支承為非對稱布置、7級精度、=1.0、 m

11、m，得 =1.429 按齒根彎曲強度計算時的齒向載荷分布系數<由1P195圖10-13> 根據b/h=10.54、 齒向載荷分配系數、<由1P193表10-3> 假設，根據7級精度，軟齒面?zhèn)鲃樱?=2.75（6） 按實際的載荷系數修正所算得的分度圓直徑 <由1P200式(10-10a)> mm（7） 計算模數5.3按齒根彎曲強度設計 <由1P198式(10-5)>1 確定計算參數（1）計算載荷系數K （2）螺旋角影響系數 <由1P215圖10-28> 根據縱向重合系數，得0.92（3）彎曲疲勞系數KFN<由1P202圖10-1

12、8> 得 （4）計算彎曲疲勞許用應力 取彎曲疲勞安全系數S=1.2 <由1P202式(10-12)>得（5）計算當量齒數ZV取26取63（6）查取齒型系數YF 應力校正系數YS<由1P197表10-5> 得 （7）計算大小齒輪的 并加以比較比較<所以大齒輪的數值大，故取0.013823。2 計算=2.99mm取35.4 分析對比計算結果對比計算結果，取=3.0已可滿足齒根彎曲強度。但為了同時滿足接觸疲勞強度，需按接觸疲勞強度算得的d191.63mm來計算應有的 取36 取91需滿足、互質5.5 幾何尺寸計算1 計算中心距阿a將a圓整為195mm2 按圓整后的

13、中心距修正螺旋角3 計算大小齒輪的分度圓直徑d1、d2 110.55mm279.45mm 4計算齒寬度 B=mm 取B1=110mm，B2105mm六、軸的設計6.1高速軸的設計1）.已知輸入軸上的功率P 、轉速n 和轉矩T高速軸：； ；材料：選用45號鋼調質處理。查課本第230頁表14-2取 C=108。2） 確定軸的最小直徑，因此根據聯軸器選擇（后面將有計算），取選用HL2型彈性套柱聯軸器。半聯徑d1=30mm,故取 d1-2=30mm,半聯軸器長度L=55mm，半聯軸器與軸配合的轂孔長度L53mm軸配合的轂孔長度L 53mm3）結構設計擬定軸上零件的裝配方案采用圖示的裝配方案4）根據軸向

14、定位的要求確定軸的各段直徑和長度（1）為使聯軸器軸向定位，在外伸端設置軸肩，則第二段軸徑。查手冊85頁表7-2，此尺寸符合軸承蓋和密封圈標準值，因此取。（2）設計軸段，為使軸承裝拆方便，查手冊62頁，表6-1，取，采用軸肩膀給軸承定位。選軸承7208，根據軸承孔徑，所以mm，長度略比軸承寬度短，取為mm.（3）齒輪分度圓直徑為71.74mm，齒輪寬度為110mm,因此,mm（4）軸承由軸肩膀定位， 取,mm，。5)校核該軸：L1=122.5 L2=183 L3=68作用在齒輪上的圓周力為：徑向力：軸向力：求垂直面的支反力：求垂直彎矩，并繪制垂直彎矩圖：求水平面的支承力：NN求并繪制水平面彎矩圖

15、：求合成彎矩圖：求危險截面當量彎矩：從圖可見，m-m處截面最危險，其合成彎矩為：（取折合系數）所以該軸是安全的。6.2 中間軸的設計：材料：選用45號鋼調質處理。查課本第230頁表14-2取C=110。根據課本第230頁式14-2得：，最小軸徑段安裝軸承，在此選擇7208軸承，因此，裝配低速級小齒輪，且取，軸長比齒寬略短取L3-2=107。段主要是定位高速級大齒輪，所以取mm，軸長比齒寬略短取L4-5=68mm。段軸肩定位齒輪，所以取mm，L4-5=7.5mm。6.3低速軸的設計：低速軸：； ；確定各軸段直徑1）計算最小軸段直徑。因為軸主要承受轉矩作用，所以按扭轉強度計算：考慮到該軸段上開有鍵

16、槽，因此根據聯軸器選擇（后面將有計算），取選用HL4型彈性套柱聯軸器，公稱直徑為1250N*m。半聯徑d=60mm,故取 d1-2=60mm,半聯軸器長度L=142mm，半聯軸器與軸配合的轂孔長度L 140mm.2）為使聯軸器軸向定位，在外伸端設置軸肩，則第二段軸徑。查手冊85頁表7-2，此尺寸符合軸承蓋和密封圈標準值，因此取。3）設計軸段，為使軸承裝拆方便，查手冊62頁，表6-1，取，采用軸肩膀給軸承定位。選軸承7214，根據軸承孔徑，所以mm，長度略比軸承寬度短，取為mm.4）齒輪孔徑為80mm，齒輪寬度為105mm,因此,mm5）軸承由軸肩膀定位， 取,mm。6），齒輪同軸肩定位，,。（

17、4）校核該軸：求作用力、力矩和和力矩、危險截面的當量彎矩。作用在齒輪上的圓周力： 徑向力：軸向力：由減速器圖可知，可知：L1=222mm L2=169.5mm L3=89.5mm求水平面的支承力。計算、繪制水平面彎矩圖。求垂直面的支反力：計算垂直彎矩：合成彎矩。扭轉切應力是脈動循環(huán)變應力，則折合系數，則 軸的計算應力： 軸的材料為45鋼，調質處理，由（2）表15-1查得：，因此 ，故安全。（5）精確校核軸的疲勞強度判斷危險截面,從應力集中對軸疲勞強度的影響，截面7應力集中最嚴重，因此需校核截面7兩側校核危險截面左側：抗彎截面系數：抗扭截面系數：彎矩及彎曲應力： 扭矩及扭轉切應力： 軸的材料為4

18、5鋼，調質處理，由（2）表15-1查得：，應力集中系數：，查附表3-2得：， 由附表3-1得軸的敏性系數為： ， 故有效應力集中系數：由附圖3-2得尺寸系數：由附圖3-3得扭轉尺寸系數：查附圖3-4表面質量系數為：軸未經表面強化處理，則：綜合系數值： 3 8碳鋼的特性系數： ，?。? ，?。簞t計算安全系數，得： 軸左截面安全 3校核危險截面右側 抗彎截面系數： 抗扭截面系數： 彎矩及彎曲應力： 扭矩及扭轉切應力： 過盈配合處的值，由附表3-8用插入法求出，并取 ，于是得：， 軸按磨削加工，由附圖3-4得表面質量系數為： 故得綜合系數為： 所以軸在危險截面右側的安全系數為： 故該軸在危險截面的右

19、側的強度也是足夠的。七、軸承的校核7.1 低速軸軸承校核由于低速軸受力最大，傳遞轉矩最大，本文只校核低速軸軸承7214的校核求兩軸承受到的徑向載荷徑向力，查1表15-1，得Y=1.4，e=0.4，派生力，軸向力，右側軸承壓緊由于，所以軸向力為，當量載荷由于，所以，。由于為一般載荷，所以載荷系數為，故當量載荷為，軸承壽命的校核故軸承壽命滿足要求。八 鍵的設計與校核:8.1高速軸鍵的校核根據，故軸段上采用鍵：, 采用A型普通鍵:綜合考慮取=45得查課本155頁表10-10所選鍵為：安全合格。8.2 中間軸鍵的校核：只校核大齒輪處的鍵，因為小齒輪處比大齒輪處長，而鍵的其它參數相同，大齒輪的合格，小齒

20、輪處也合格。因為d=45裝齒輪查課本153頁表10-9選鍵為查課本155頁表10-10得因為L1=70mm初選鍵長為63mm,校核所以所選鍵為: 安全合格。6.3低速軸齒輪處的鍵校核：因為d=80裝聯軸器查課本153頁表10-9選鍵為查課本155頁表10-10得因為L1=70初選鍵長為,校核所以所選鍵為: 安全合格。6.4低速軸聯軸器處的鍵校核：因為d=50裝聯軸器查課本153頁表10-9選鍵為查課本155頁表10-10得因為L1=100初選鍵長為,校核所以所選鍵為: 安全合格。九.低速軸聯軸器的選擇：9.1輸入軸聯軸器計算聯軸器所需的轉矩： 查課本269表17-1取 查手冊94頁表8-7選用

21、型號為HL2的彈性柱銷聯軸器。9.2輸出軸聯軸器計算聯軸器所需的轉矩： 查課本269表17-1取 查手冊94頁表8-7選用型號為HL4的彈性柱銷聯軸器。十. 潤滑方式的確定因為傳動裝置屬于輕型的，且傳速較低，所以其速度遠遠小于，所以采用油潤滑，箱體內選用SH0357-92中的50號潤滑，裝至規(guī)定高度。十一 減速器機體結構尺寸如下名稱符號計算公式結果箱座厚度10箱蓋厚度10箱蓋凸緣厚度20箱座凸緣厚度20箱座底凸緣厚度20地腳螺釘直徑M16地腳螺釘數目查手冊4軸承旁聯結螺栓直徑M8蓋與座聯結螺栓直徑=（0.5 0.6）M12軸承端蓋螺釘直徑=（0.40.5）M8視孔蓋螺釘直徑=（0.30.4）M

22、6定位銷直徑=（0.70.8）8，至外箱壁的距離查手冊表112271919，至凸緣邊緣距離查手冊表1123027外箱壁至軸承端面距離=+（510）30大齒輪頂圓與內箱壁距離>1.226齒輪端面與內箱壁距離>12.5箱蓋，箱座肋厚88軸承端蓋外徑+（55.5）106（1軸）116（2軸）166（3軸）參考文獻：1濮良貴 紀名綱 主編 機械設計第七版 高等教很出版社 20002王昆 何小柏 汪信遠 主編 機械設計課程設計高等教育出版社 1995 3 機械設計手冊編輯委員會.機械設計手冊（1-2）第三版M.北京：機械工業(yè)出版社，2004Two-way conveyorDocument T

23、ype and Number:United States Patent 5000657 Link to this page: Abstract:A two-way conveyor having an accumulating station for accumulating a plurality of sheets. A mechanism for determining in which direction the sheets are to be moved is also provided as well as a mechanism for moving the sheets in

24、 one direction or the other. A thickness detecting mechanism is also provided to determine the thickness of the stack and the stack is moved in one direction or the other depending on its thickness. Gates are provided for preventing the movement of the stack in either direction which comprises gates

25、 at the forward and rearward edge of the stack and a closing mechanism is provided for closing the gate to prevent movement of the stack in either direction. Gate opening mechanisms are provided for opening one of said gates to permit movement of the stack in the desired direction. The gates are pre

26、ferably pivotal gates located at the forward and rearward portions of the stack. Inventors:Gunther Jr., William H. (Mystic, CT) Application Number:07/299666 Filing Date:01/23/1989 Publication Date:03/19/1991 Export Citation:Click for automatic bibliography generation Assignee:GUNTHER INTERNATIONAL L

27、TD (US) US Patent References:2641974June, 1953Sperling et al.414/790.3Apparatus for cutting and stacking sheets3182537May, 1965Grody414/790.3Paper cutting machine with counter controlled stacking means3830144August, 1974Kuckhermann et al.414/790.7APPARATUS FOR FORMING AND CONVEYING STACKS OF FLAT WO

28、RKPIECES4363584December, 1982Kokubo414/789.9Paper sheet accumulator assembly and bank note dispenser provided therewithPrimary Examiner:Spar, Robert J. Assistant Examiner:Krizek, Janice Attorney, Agent or Firm:Stoll, Previto & Hoffman Claims:The embodiment of the invention in which as exclusive

29、property or privilege is claimed are claimed as follows:1. A two-way sheet-directing mechanism comprising means at an accumulating station for accumulating sheets, means for determining in which direction the sheets are to move and for moving the sheets in one direction or the other, said accumulati

30、ng station being adapted to receive a plurality of sheets in a stack, said direction-determining means comprising means to determine the thickness of the stack and wherein the stack is moved in one direction or the other depending on the thickness of the stack, said accumulating station comprising g

31、ate means for preventing the movement of the stack in either direction, and said gate means comprising gates at the forward and rearward edge of the stack wherein means are provided for closing the gates to prevent movement of the stack in either direction. 2. A mechanism as claimed in claim 1 where

32、in means are provided for opening one of said gates to permit movement of the stack in the desired direction. 3. A mechanism as claimed in claim 2 wherein said gates are pivotal gates located at the forward and rearward portions of the stack. 4. A mechanism as claimed in claim 3 wherein pusher means

33、 are adapted to push the stack in one direction or the other. 5. A mechanism as claimed in claim 4 wherein a pair of pusher means are provided which, upon activation, push the stack in one direction or the other. 6. A mechanism as claimed in claim 5 wherein said pusher means are mounted on separate

34、drive mechanisms and the activation of said drive mechanism permits the stack to move in one direction or the other. 7. A mechanism as claimed in claim 6 wherein said drive mechanism comprises a chain mechanism. 8. A mechanism as claimed in claim 7 wherein a main drive mechanism is provided and wher

35、ein the pusher drive mechanism is in relationship to said main drive mechanism. 9. A mechanism as claimed in claim 8 wherein each directional drive mechanism is selectively engaged by the main mechanism in order to move the stack in one direction or the other. Description:BACKGROUND The present inve

36、ntion relates to a two-way conveyor and, more particularly, to a two-way conveyor mechanism which permits stacks to be moved either in one direction or in the opposite direction depending upon the size of the stack. During certain automatic operations where stacks of sheets are processed and inserte

37、d into envelopes, depending upon its thickness, the stack is either placed on an envelope blank which is folded around the stack to form an envelope or the stack is inserted (stuffed) into a pre-formed envelope. Heretofore, when envelopes of different sizes are necessary because stacks of different

38、thicknesses are to be inserted therein, it was necessary to either determine what the size of the envelope would be and thereafter place the stack for a particular size envelope into a particular machine for stuffing purposes or to place the stack in a different machine to be stuffed into an envelop

39、e. As will be appreciated, these are time consuming operations and not well suited to high speed stuffing. Alternately, it was sometimes necessary to manually take a particular stack from the stacking machine and place it in the proper enveloping machine. OBJECT OF INVENTION The present invention ov

40、ercomes these problems and has for one of its objects the provision of a mechanism which will automatically move the stack either to an envelope folding mechanism or to a stuffing mechanism. Another object of the present invention is to provide a two-way diverter mechanism in a single module which w

41、ill automatically move the stack in one direction to an envelope stuffing mechanism or in the opposite direction to an envelope folding mechanism. BRIEF DESCRIPTION OF INVENTION The improved diverter mechanism comprises a stacking area in which sheets accumulate. A pair of diverter sprocket wheels w

42、ith pushers attached hereto are provided. The pushers are mounted on separate conveyor chains which move in opposite directions. If the stack of sheets is to be moved in the usual forward direction, the main conveyor chain, through its pushers, moves the stack in the forward direction. If the stack

43、is to be moved in the opposite direction, diverter sprocket means are activated to move a diverter conveyor and pushers to strike one edge of the stack and move the stack along the conveyor in the opposite direction. DESCRIPTION OF CONVEYOR FIG. 1 is a schematic view of a mechanism with which the tw

44、o-way conveyor mechanism of the present invention may be used. FIG. 2 shows a schematic view of the mechanism for moving the stack in opposite directions. DESCRIPTION OF INVENTION Referring to the drawings and more particularly to FIG. 1, the sheets are stacked in a stack S in a stacking area A. The

45、 mechanism feed sheets of paper P one-by-one to the stacking area A from a feeder assembly F. The sheets are scanned by a laser scanner L which activates a computer to determine how many sheets P are to be in the stack S before they are moved out of the stacking area A. When the laser scanner L coun

46、ts the correct number of sheets p to be stacked in the stack S in stacking area A, they are moved to an enveloping station. In one direction, the stack S of sheets p are fed to an envelope mechanism C which folds the envelope around the stack S as is fully described in my U.S. Pat. Nos. 4,694,631 an

47、d 4,694,632. In the opposite direction, the stack is moved to an envelope stuffing station E where the stack of sheets S is stuffed into a larger envelope D. The sheets P are fed by the feeder F to the stacking area A which comprises a stacking plate 1 of side guides 2A and 2B at each end thereof pi

48、votally mounted around pivot 3 for upward movement. Both side guides 2A and 2B are lowered during the feeding operation in order to permit the sheets P to be stacked in stack S on stacking plate 1 in a uniform manner. After the sheets S are fed and they are to be moved in either direction to be enve

49、loped, either one of the side guides 2A or 2B are pivoted upwardly to permit the stack S of sheets p to be moved in either direction. As the sheets p are stacked on a stacking plate 1, the side guides 2A and 2B are in their downward position as shown in FIG. 2. In this position, the sheets P accumul

50、ate in the stack S until the necessary predetermined number of sheets P are accumulated thereon. When this occurs, either the front guide 2A or the rear guide 2B is pivoted upwardly and the stack S of sheets P is free to move in one direction or another. If the stack is not too thick and an envelope

51、 can be wrapped around it, the front guide 2A pivots upwardly and the stack moves in one direction to have an envelope wrapped around it. However, if the stack is much larger and too thick to have an envelope folded around it, when the sheets reach the desired thickness, the rear guide 2B is pivoted

52、 upwardly thereby permitting the stack S to move in the opposite direction to be thereafter moved to the envelope module E so that they can be stuffed into a larger envelope D. The moving means for moving the stack comprise a main conveyor chain 4 having a plurality of pushers 5 thereon and a divert

53、er chain 7 provided with pushers 6. The main conveyor chain 4 is provided with and is operated by a main conveyor drive roller (not shown) which is wrapped around a main idler roller 8. Pushers 5 are triangular in shape and each has a forward face 10 which is adapted to strike the rear edge of the stack S of sheets P to move it forward. The main conveyor chain 4 moves in a forward direction only. The pushers 5 thereon are attached to it s