Tension head for modular steel strapping machine

A self-actuating tension head for of a strapping machine for feeding a steel strapping material around a load, tensioning the strapping material and sealing the strapping material to itself, the tension head, comprising:

• a body defining a strap path therethrough;
• a drive wheel defining an axis of rotation;
• a tension wheel defining an axis of rotation, the drive wheel axis of rotation being a fixed distance from the tension wheel axis of rotation, the drive wheel and tension wheel being operably engaged with one another;
• a pinch wheel defining an axis of rotation, the strap path extending between the tension wheel and the pinch wheel;
• a first link operably connecting the drive wheel and the tension wheel, the first link defining a first pivot arm, the first link being pivotable about the drive wheel axis of rotation;
• and
• a second link operably connecting the tension wheel and the pinch wheel, the second link defining a second pivot arm, the second link being pivotable about the pinch wheel axis of rotation, the second link being movable along the second pivot arm to move the tension wheel into and out of engagement with the pinch wheel, the first and second pivot arms defining an energizing angle therebetween,
• wherein the energizing angle decreases as the tension wheel is moved into engagement with the pinch wheel and the energizing angle increases when a gap is opened between the tension wheel and the pinch wheel.