34
UpperTensionDevice
Howitworks
TheTensionDiscsandCheckSpringareassembledonthe
UpperTensionBarwhichpassesthroughtheuppertension
plateandispinnedagainsttheTensionRegulatorSpring.
TheTensionRegulatorPinpassesthroughabushingattached
totheuppertensionplateandpressesagainsttheTension
RegulatorSpring.
AsthepressurefromtheTensionRegulatorPinonthe
TensionRegulatorSpringincreases,theTensionDiscsare
squeezedtogethertighter.
TheSeparatingDiscbetweenTensionDiscsallowstheuseof
2threads(oneoneitherside)fortwinneedlesewing.
TosoftenthesharptugsoftheThreadTake‐upLeveronthe
thread,theupperthreadtensiondeviceisequippedwitha
CheckSpring,whichconsiderablyreducesthedangerofthe
threadbreaking.
ThenumberedTensionRegulatorDial(‐0to9+)
hasaspiralrampwheretheTensionRegulator
Pinrides.
Asthedialisturnedfrom(0)towards(9),the
ramppushestheTensionRegulatorPinwhich
pushesontheUpperTensionSpring,this
squeezestheTensionDiscstogether.
WhenThePresserFootLeverisraised,itpushes
theReleasePinout.TheReleasePinpusheson
theUpperTensionBarandreleasesthespring
tensionontheTensionDiscs,allowingthetop
threadtopullfreelythroughtheTensionDiscs
forthreadingthemachineorremovingthe
materialbeingsewn.