Abstract: Apparatus and methods for mixing and dispensing components. The methods and apparatus of the invention are particularly advantageous to manually mix the components of radiopaque bone cement and inject the resulting radiopaque bone cement into skeletal structures. The manually actuated apparatus of the invention comprises: (1) a sealed mixing chamber for mixing components; (2) a dispensing chamber isolated from the sealed mixing chamber; (3) a controllable portal to open a flow path between the sealed mixing chamber and the dispensing chamber so that the dispensing chamber can receive the mixed components after they are mixed; and (4) a drive mechanism associated with the dispensing chamber to force the mixed contents from the dispensing chamber.

Abstract: A roof scuttle safety railing system is provided for an existing or new roof scuttle which railing may be installed on the roof scuttle by unskilled labor without compromising the integrity of the weather seal of the roof scuttle. In one embodiment, pivotal corner brackets are secured to the capflashing of a roof scuttle with the vertical members of the safety railing being inserted in openings in the brackets. In another embodiment, an elongated bracket is used along two opposed sides of the roof scuttle which brackets are firmly held against the outside walls of the roof scuttle by tie rods, a strap or a cable. The elongated bracket has vertical openings at its distal ends for securing the vertical members of the safety railing and horizontal openings or slots for the tie rods, straps or cables. A hinged gate is also provided which preferably has a self-closing hinge.