Stackable plastic damper

A viscous damper arrangement for retarding rotation of a shaft, comprising a plurality of damper units, each unit comprising:

• a rotor adapted to be connected to the shaft for rotation therewith, the rotor having a disk shaped to extend radially and coaxially from the shaft, and
• a housing surrounding both opposite sides of said disk providing a gap between said housing and at least one face of said disk, said housing providing a fitting for injecting viscous material into said gap, said housing providing means for connecting said housing to an identical housing of another damper of said plurality of damper units arranged axially aligned and adjacently thereto, and said housing providing a means for selectively connecting said housing to a framework to selectively prevent rotation of said housing with respect to said framework.

A viscous damping unit assembly for retarding the unrolling and lowering speed of a curtain-type fire door coiled on a horizontal shaft, said shaft rotatably mounted to a stationary framework, comprising a plurality of damper units, each unit comprising:

• a rotor connectable to the shaft for rotation therewith, the rotor having a disk shaped to extend radially and coaxially from the shaft, and
• a housing surrounding both opposite sides of said disk providing a gap between said housing and at least one face of said disk, said housing providing a fitting for injecting viscous material into said gap, said housing providing means for connecting said housing to an identical housing of another damping unit assembly arranged axially aligned and adjacently thereto, and said housing providing a means for selectively fixing said housing to the framework to selectively prevent rotation with respect to the framework.

A viscous damper arrangement for retarding rotation of a shaft, comprising:

• a rotor connectable to the shaft for rotation therewith, a rotor having a disk shaped to extending radially and coaxially from the shaft;
• and
• a housing surrounding both opposite sides of said disk providing a gap between said housing and at least one face of said disk, said housing providing a fitting for injecting viscous shear resistant material into said gap, said housing and said rotor both comprising reinforced composite cast plastic material.