14. May dao nhieu gau
a. Cong dung - phan loai:
* Cong dung:
May dao nhieu gau la loai may lam dat hoat dong lien tuc va co nang suat cao. Dung de dao ranh dat duong day dien ngam, duong ong dan nhien lieu, dan nuoc, cac giao thong hao trong quan su.
Trong thuy loi, dung de thi cong muong mang, nao vet bun khoi thong dong chay.
Trong linh vuc khai thac dung de khai thac dat va khoang san o cac mo lo thien.
* Phan loai:
May dao nhieu gau co the duoc phan loai theo cac cach sau:
+ Theo ket cau cua thiet bi cong tac:
- May dao nhieu gau he xich (gau duoc gan vao dai xich).
- May dao nhieu gau he ro-to (gau duoc gan vao vanh ro-to).
+ Theo phuong lam viec cua thiet bi cong tac:
- May dao doc (phuong lam viec cua thiet bi trung voi phuong di chuyen cua may).
- May dao ngang (phuong lam viec cua thiet bi vuong goc voi phuong di chuyen cua may).
+ Theo dung tich gau:
- Loai co nho (dung tich gau tu 0,050,1m3).
- Loai co vua (dung tich gau tu 0,050,45m3).
- Loai co lon (dung tich gau tu 0,454,5m3).
+ Theo cong dung:
- May chuyen khai thac dat, quang v.v...
- May chuyen dao duong hao, ranh, muong v.v...
Ngoai ra, con co the phan loai may theo he thong di chuyen, nguon dong luc v.v...
Uu diem (So voi may dao mot gau):
- Nang suat cao hon, thuong gap tu 1,52,5 lan khi chung co cung cong suat.
- Trong luong rieng (tinh tren mot don vi nang suat) nho hon. Voi hai may dao co cung nang suat, trong luong cua may dao nhieu gau nho hon may dao mot gau tu 1,52 lan.
- Nang luong tieu hao rieng (tinh tren mot don vi dung tich gau) nho hon.
Nhuoc diem:
- Thieu tinh van nang.
- Gia thanh che tao dat.
- Khoi luong cong viec cham soc, bao duong ky thuat lon v.v..
b. Cau tao va nguyen ly hoat dong
+ May dao doc nhieu gau he xich
Hinh 3-13. May dao nhieu gau dao doc he xich
1- Gau; 2- Xich; 3- Dia xich chu dong; 4- Pheu do vat lieu; 5- Bang tai; 6- Dong co; 8- Bo di chuyen xich.
Hinh 3-14. Cau tao cua gau
a- Kieu xa dat tu do; b- Xa cuong buc; 1- Dai gau; 2- Than gau; 3- Rang phu; 4- Rang phu chong ket; 5- Lo kep chan rang; 6- Rang chinh
May dao doc nhieu gau he xich duoc su dung de dao muong, ranh, giao thong hao 0,2 - 3,6 m, chieu sau ranh 0,5 - 8m. Cau tao cua may (hinh 3-13) gom: Cac gau 1 duoc gan tren xich keo gau 2, dia xich chu dong 3, pheu do vat lieu 4, bang tai 5, dong co 6, ban dieu khien 7, bo di chuyen xich 8. Gau la bo phan cong tac chu yeu cua may, duoc che tao tu thep tam co do day tuy thuoc vao dung tich gau (tu 6 den 10mm). Theo qua trinh do tai, co loai gau do tai cuong buc va gau do tai tu do. Hinh dang ket cau cua gau duoc the hien o hinh 3-14. Hinh 3-15. So do nguyen tac hoat dong cua may dao nhieu gau
1- Xich; 2- Gau; 3- Banh sao chu dong; 4- Bang tai; 5- Banh doi huong ; 6- Khung; 7- Co cau dieu chinh.
Nguyen ly lam viec cua may duoc mo ta qua so do 3-15 nhu sau: xich 1 tren co gan cac gau 2 se nhan duoc luc keo tu banh sao chu dong 3 de keo cac gau vao cat dat. Dat nam trong gau 2 se tiep tuc duoc do vao bang tai 4 de van chuyen sang phia suon ben cua may. Toan bo he thong cong tac duoc ga lap tren khung 6. Khi xich bi trung, dieu chinh do cang xich nho co cau dieu chinh 7. De tao do nghieng cua ranh dao va xe bac cho vach, tren may co lap cac thiet bi cong tac phu nhu truc vit hoac xich cat.
+ May dao doc nhieu gau he roto
Hinh 3-16. Cau tao chung cua may dao doc nhieu gau kieu ro to.
a- May co thiet bi cong tac kieu ro to; b- May lap bo phay dat; 1- Dong luc; 2- Bo truyen dong; 3- Co cau nang ha vanh gau; 4- Bang tai van chuyen dat; 5- Vanh gau; 6- Khung lap vanh gau; 7- Vanh chan.
Dac diem cua loai may nay la cac gau deu duoc lap chat tren vanh gau tron cung. So voi may kieu xich, may nay co toc do cat dat lon hon, nang suat cao hon, nang luong tieu ton nho hon. Nhuoc diem cua may la bo cong tac nang ne, cong kenh, duong kinh ro to kha lon (gap 1,5 lan chieu sau ranh dao), chieu sau dao bi han che (bang 1/2 so voi may dao he xich).
Hinh thuc cau tao cua may dao doc nhieu gau kieu ro to co hai loai chinh: loai dung ro to de dao dat va loai phay dat. Hinh dang chung cua hai loai may nay duoc the hien tren hinh 3-16
+ May dao ngang nhieu gau
Nguyen ly hoat dong cua may tuong tu nhu may he xich, dat duoc cac gau cat va dua len cao do vao bang tai, gau cua may la bo cong tac quan trong nhat.
Khi dao kenh muong va trong khai thac mo lo thien thuong dung cac loai may dao ngang ca he xich va ro to. Dac diem cua cac loai may nay la huong dao vuong goc voi huong di chuyen cua may. Nang suat cua may toi hang tram m3/h. Hinh 3-18 the hien so do cau tao cua may dao ngang ro to.
Hinh 3-18. May dao ngang nhieu gau kieu ro to
1- Ro to mang gau xuc; 2- Can; 3- Bang tai; 4- Xi lanh thuy luc; 5- Ca bin; 6- Cum bom; 7- Gia do; 8- Co cau di chuyen; 9- Co cau dan dong quay; 10- Co cau quay; 11- Toa quay; 12- May phat dien; 12- Bang tai xa dat; 14- Dong co va cum tang toi dan dong bang tai; 15- Xi lanh thuy luc dieu chinh do cao cua bang; 16- Dong co va tang dan dong bang tai; 17- Dong co dien; 18- Bang tai co gan tang cuong de chuyen dat voi do doc lon.
b- Cach tinh nang suat may xuc nhieu gau
Trong do: q- dung tich hinh hoc cua gau, lit;
n- so gau xa dat trong mot phut;
kd- he so day gau;
kx- he so toi xop cua dat;
ktg- he so su dung thoi gian.
Nang suat thuc te cua may duoc tinh theo cong thuc:
Trong do: B- Chieu rong ranh dao, m;
H- Chieu sau ranh dao, m;
V1- Van toc di chuyen may khi lam viec, m/s.
