Mitre joint support
A support for a mitre joint uses two wedging mechanisms disposed at a characteristic angle. Each wedging mechanism is arranged to locate inside a hollow rail, such as within an extruded hollow beam. The wedging mechanism can be operated from outside the joint in order to clamp the mechanism in position. The mechanism has a self centering capability to assist in accurately locating the rails relative to each other.
1. A support for a mitre joint, the support having a central region, the support having a first arm extending away from the central region in a first direction and a second arm extending away from the central region in a second direction, the second direction being angled with respect to the first direction by a given angle;
each of the first arm and the second arm having:
(d) a fixed portion oriented generally in the respective first or second direction; the fixed portion having an outer surface, and having an inner surface opposed to the outer surface and inclined relative to the respective first or second direction at an inclination angle;
(e) a moveable portion arranged to move generally in the respective first or second direction, the moveable portion having an outer surface opposed to an inner surface, the inner surface being inclined relative to the outer surface at the inclination angle; and
(f) an adjustment mechanism arranged to move the moveable portion;
wherein the inner surface of the moveable portion is arranged to abut the inner surface of the fixed portion, with the outer surface of the moveable portion being generally aligned in the respective first or second direction;
the support having a first continuous outer surface incorporating the outer surface of the fixed portion of the first arm, and a second continuous outer surface incorporating the outer surface of the second arm;
the central region having a first pressing face, the first pressing face extending between the first continuous outer surface and the second continuous outer surface, the first pressing face being angled with respect to the first direction by a pressing angle which is less than the given angle.
2. A support for a mitre joint as claimed in claim 1 , wherein the central region has a second pressing face, the second pressing face extending between the inner surfaces of the respective fixed portions of the first and second arms.
3. A support for a mitre joint as claimed in claim 2 , wherein the first pressing face is parallel to the second pressing face.
4. A support for a mitre joint as claimed in claim 1 , wherein the pressing angle is 50% of the given angle.
5. A support for a mitre joint as claimed in claim 4 , wherein the central region has a second pressing face, the second pressing face extending between the inner surfaces of the respective fixed portions of the first and second arms.
6. A support for a mitre joint as claimed in claim 5 , wherein the first pressing face is parallel to the second pressing face.
7. A support for a mitre joint as claimed in claim 1 , wherein the given angle is 90°.
8. A support for a mitre joint as claimed in claim 7 , wherein the pressing angle is 45°.
9. A support for a mitre joint as claimed in claim 1 , wherein the adjustment mechanism is a linear actuator.
10. A support for a mitre joint as claimed in claim 9 , wherein the linear actuator is a lead screw having a head located within the central region of the support.
11. A support for a mitre joint as claimed in claim 10 , wherein the central region has a second pressing face, the second pressing face extending between the inner surfaces of the respective fixed portions of the first and second arms, and the lead screw extends through the second pressing face.