US 3,994,471 A · Ply joint bar

Abstract

A ply joint bar for casting a seamless ceiling from a hardening material such as plaster or concrete, poured over the surfaces of adjacent molding panels, has a bridge with a lower surface resting on and flush with two such adjacent panels and an upper gable-like portion adapted to be anchored in the hardened casting material, an optional base member with two adjacent coplanar surfaces which grasp the underside of the panels, and a leg frangibly connected at one of its ends to the bridge and permanently connected at its other end to the base member, so as to separate adjacent panels sandwiched between the bridge and base member. After the casting material hardens, the molding panels are removed and the frangible leg separated from the bridge leaving a substantially seamless ceiling surface with the bridge embedded therein and its lower surface flush therewith.

Claims14

Dependent claims

A joint bar for preventing formation of a seam in cast material in the area between the edges of two panels having planar surfaces on which the material is to be cast comprising:

a bridge member having an upper surface with anchor means projecting from said upper surface adapted for affixing said bridge member in the casting material poured thereover and hardened, and a substantially flat lower surface adapted to engage the upper surfaces of the panels so that said lower surface is substantially contiguous with the panel surfaces and
a leg member attached to said lower surface, the edges of the panels being located adjacent said leg member, said leg member being frangible adjacent the lower surface to be broken away when the panels are removed so that said lower surface of said bridge member remains substantially smooth when said leg member is broken therefrom.

Dependencies are inferred from the claim text.

Ply joint bar

Life of this patent

Ply joint bar

Life of this patent

Abstract

Claims14