1. Field of the Invention
THIS INVENTION relates to dowel sleeves.
In particular, the invention relates, but is not limited to, dowel sleeves for the construction of concrete slabs; and to parts or components for the dowel sleeves.
Throughout the specification, the term “construction plate” shall be used to include key joint plates, contraction plates and expansion plates for the construction of concrete slabs; and like construction plates used in building construction.
2. Prior Art
Dowel sleeves, which are typically of circular or rectangular cross-section, are commonly used to accommodate expansion and/or contraction of adjacent concrete slabs at a joint, where one end of each dowel is “locked” into one of the concrete slabs and the other end is slidably received within a respective dowel sleeve to allow controlled lateral movement, relative to the joint, between adjacent concrete slabs in a generally horizontal direction (i.e. along an axis substantially perpendicular to the joint between the adjacent slabs; but limiting any horizontal (or lateral) movement (i.e., along an axis parallel to the joint) and/or any vertical displacement between the adjacent concrete slabs.
Typically, the prior art dowel sleeves are formed from plastics material (which may have been wholly- or partially-recycled); where one end (i.e., the outer end) of the dowel sleeve is fixed, e.g., by nailing to a construction plate, and the other end is supported by an integral leg or a “chair”, to locate the dowel sleeve before the concrete is poured for the concrete slab in which at least a portion of the dowel sleeve is to be embedded.
The one (or outer) end may be engaged with an end cap, of complementary external shape, nailed or otherwise fixed to the construction plate.
Alternatively, the one (or outer) end of the dowel sleeve may be engaged in complementary formation(s) on the construction plate.
The workers installing the dowel sleeves must align each with respective holes through the construction plate, where the dowels extend through the holes; fix the one (or outer) ends of the dowel sleeves to the construction plate; and align and support the dowel sleeves so that they will not be displaced prior to/during the concrete pour to ensure the designed (or allowable) relative expansion/contraction movement between the slabs can be achieved without unwanted horizontal (lateral) and/or vertical displacement between the adjacent concrete slabs.