Umthamo webhakede isilinganiso sevolumu ephezulu yezinto ezingahlaliswa ngaphakathi kwebhakede le-backhoe excavator.Umthamo webhakede ungalinganiswa ngomthamo wokushaywa noma umthamo onqwabelene njengoba kuchazwe ngezansi:
Umthamo wokushaywa uchazwa ngokuthi: Umthamo wevolumu yebhakede ngemva kokuba lishaywe endizeni yokuteleka.Indiza yesiteleka idlula emaphethelweni angemuva aphezulu ebhakedeni kanye nonqenqema lokusika njengoba kuboniswe ku-Fig. 7.1 (a).Lo mthamo we-struck ungalinganiswa ngokuqondile ngemodeli ye-3D ye-backhoe ye-excavator yebhakede.
Ngakolunye uhlangothi ukubalwa komthamo onqwabelene kwenziwa ngokulandela amazinga.Emhlabeni jikelele izindinganiso ezimbili ezisetshenziswayo ukunquma umthamo oyinqwaba, yilezi: (i) SAE J296: “Isilinganiso sevolumu yebhakede elincane ne-backhoe”, indinganiso yaseMelika (Mehta Gaurav K., 2006), (Komatsu, 2006) (ii) CECE ( I-Committee of European Construction Equipment) izinga laseYurophu (Mehta Gaurav K., 2006), (Komatsu, 2006).
Umthamo onqwabelene uchazwa ngokuthi: Isamba somthamo we-strike kanye nevolumu yezinto ezithe xaxa ezinqwabelene ebhakedeni nge-engeli engu-1:1 yokuphumula (ngokuvumelana ne-SAE) noma nge-engeli engu-1:2 yokuphumula (ngokuvumelana ne-CECE), njengoba kuboniswe kumfanekiso 7.1 (b).Lokhu akusho neze ukuthi igeja kufanele liphathe ibhakede liqondiswe kulesi simo sengqondo, noma ukuthi yonke into ngokwemvelo izoba ne-engeli engu-1:1 noma engu-1:2 yokuphumula.
Njengoba kubonakala ku-Fig. 7.1 umthamo we-Vh onqwabelene unganikezwa ngokuthi:
Vh=Vs+Ve ….(7.1)
Lapho, i-Vs iwumthamo we-strike, futhi i-Ve iwumthamo wezinto ezibonakalayo oweqile obuthelwe ku-1:1 noma ku-engeli engu-1:2 yokuphumula njengoba kuboniswe ku-Fig. 7.1 (b).
Okokuqala, kusukela ku-Fig. 7.2 umthamo we-struct Vs uzokwethulwa, bese kusetshenziswa izindlela ezimbili ze-SAE ne-CECE, izibalo ezimbili zevolumu yezinto ezidlulele noma umthamo we-Ve zizokwethulwa ku-Fig. 7.2.Ekugcineni umthamo webhakede onqwabelene ungatholwa kuzibalo (7.1).
Umdwebo 7.2 Isilinganiso somthamo webhakede (a) Ngokwe-SAE (b) Ngokwe-CECE
- Incazelo yamagama asetshenziswe ku-Fig. 7.2 imi kanje:
- LB: Ukuvuleka kwebhakede, kukalwa ukusuka onqenqemeni kuya ekugcineni kwepuleti elingemuva lesisekelo sebhakede.
- I-Wc: Ububanzi bokusika, obukalwa phezu kwamazinyo noma izinqamuli eziseceleni (qaphela ukuthi imodeli ye-3D yebhakede ehlongozwayo kule thesis eyomsebenzi wokwakha olula kuphela, ngakho abasiki baseceleni abanamathiselwe kumodeli yethu).
- I-WB: Ububanzi bebhakede, likalwa phezu kwezinhlangothi zebhakede odebeni olungezansi ngaphandle kwamazinyo abasiki bezinhlangothi abanamathiselwe (ngakho lokhu ngeke futhi kube ipharamitha ebalulekile engu-108 yemodeli yebhakede ehlongozwayo ye-3D njengoba ingenazo izisiki eziseceleni).
- I-Wf: Ngaphambili kobubanzi obungaphakathi, kukalwa ngonqenqema olusikiwe noma izivikeli eziseceleni.
- I-Wr: Ngaphakathi ububanzi bangemuva, kukalwa engxenyeni encane engemuva kwebhakede.
- I-PArea: Indawo yephrofayili eseceleni yebhakede, eboshwe i-contour yangaphakathi kanye nendiza eshayayo yebhakede.
Umdwebo 7.3 ubonisa imingcele ebalulekile yokubala umthamo webhakede wemodeli ye-3D ehlongozwayo yebhakede.Isibalo esenziwe sisekelwe ezingeni le-SAE njengoba leli zinga lamukeleka emhlabeni wonke futhi lisetshenziswa.