Tension rod mechanism

A tension mechanism for joining a first outer shaft and a second inner shaft of a tension rod, the first outer shaft having an inner surface and the second inner shaft having an inner surface and an end surface, the second inner shaft being slidably received within the first outer shaft, such that the tension rod is adjustable in length, the tension rod having a longitudinal axis, the tension mechanism comprising:

• a partially threaded rod having a threaded portion and a first end extending from the threaded portion and adapted to be fixed to the second inner shaft and a second end opposite thereto, the second end of the partially threaded rod having a tapered body with a first transverse dimension at a first point along the longitudinal axis and a second transverse dimension at a second point along the longitudinal axis, the second point being closer to the second end than to the first end, and the second transverse dimension being greater than the first transverse dimension;
• a nut threadedly engaged with the threaded portion of the partially threaded rod;
• a wedge having an inner surface and an outer surface, the inner surface being in facing sliding engagement with the tapered body between the nut and the second end of the partially threaded rod, the wedge including a longitudinally extending slot,
• the nut for being rotationally fixed to the first outer shaft so that upon rotation of the second inner shaft with respect to the first outer shaft, the threaded portion of the partially threaded rod rotates with the second inner shaft such that the nut is moved along the longitudinal axis by the partially threaded portion toward the second end of the partially threaded rod,
• the wedge being in abutting engagement with the nut so upon a movement of the nut along the partially threaded rod, the wedge moves with the nut,
• the wedge being configured so that, upon the inner surface of the wedge contacting the tapered body as the wedge moves along the longitudinal axis from the first point to the second point, the wedge expands radially outwardly and the outer surface of the wedge makes contact with the inner surface of the first outer shaft, preventing relative movement between the first outer shaft and the second inner shaft to lock the position of the first outer shaft with respect to the second inner shaft.