Tension device for producing an initial tension on a wire cable
An initial tension device has a wire cable for connecting a drive unit and a movable member, a tension case fixed to an immovable member, a regular retainer engageable with an outer cable of the wire cable, and a slot formed in the tension case to extend in the longitudinal direction of the wire cable. The regular retainer engaged with the outer cable moves together with the outer cable by the tension applied to the wire cable through the length defined by the slot. The regular retainer is engaged with the outer cable in the state where a maximum tension is applied to the wire cable.
1. A device which applies an initial tension to a wire cable which transmits driving power of a drive unit to a movable member, comprising:
a tension case adapted to be fixed to a vehicle body, said tension case having an elongated space along a longitudinal direction of the wire cable;
an insertion part connected to an end part of an outer cable of the wire cable and inserted into the elongated space;
a first retainer having an inside part engageable with the insertion part in a plane transverse to the longitudinal direction of the wire cable, first slots above the inside part and second slots above the first slots; and
a two-stage slot formed in the tension case and extending in the longitudinal direction of the wire cable, said two-stage slot having a wide slot and a narrow slot corresponding in width with a width of a portion of the first retainer disposed between the second slots;
wherein the wide slot and the narrow slot are coplanar so that a front end of the narrow slot communicates with the wide slot;
wherein in a first position of said first retainer said first retainer is held out of engagement with the insertion part and the first slots are engaged with edges of the wide slot so as to permit the wire cable to be tensioned to a selected tension;
wherein the first retainer is moved from the first position to a second position by moving said first retainer down in said wide slot into engagement with the insertion part and moving, said first retainer in the tension case parallel to the longitudinal direction of the wire cable to engage the second slots with edges of the narrow slot.
2. The device according to claim 1 , wherein said first retainer is engaged with the insertion part when the wire cable is at the selected tension.
3. The device according to claim 1 , wherein said first retainer comprises an inclined projection engaged with the edges of the wide slot to keep the first retainer at the first position where the first retainer is disengaged from the insertion part.
4. The device according to claim 1 , further comprising a clearance provided in the tension case, and a second retainer inserted into the clearance.
5. The device according to claim 4 , wherein said second retainer is engaged with a rear end part of the insertion part when said second retainer is inserted into the clearance.
6. The device according to claim 1 , wherein upper edges of the first slots are formed by projections which permit the first retainer to be moved down into engagement with the insertion part.