Abstract: A knockdown, portable lift is relatively compact and lightweight for transport and use where there is no existing means for lifting a load between a lower surface and an upper surface or where the existing means cannot be used. Components of the lift are stored in a base portion of the lift and are assembled on site for forming a lift frame extending between the upper and lower surfaces. A platform and drive assembly are supported on the lift frame and are driven together up and down tracks on each side of the lift frame using a rotary drive, such as a hand crank or electric motor, to power the drive assembly. The drive assembly is operable by a person on or off the platform from either the upper or lower surface or traversing stairs over which the platform is moving. The drive assembly incorporates a unique overspeed braking system and a unique clutch arrangement.

Abstract: A knockdown, portable lift is relatively compact and lightweight for transport and use where there is no existing means for lifting a load between a lower surface and an upper surface or where the existing means cannot be used. Components of the lift are stored in a base portion of the lift and are assembled on site for forming a lift frame extending between the upper and lower surfaces. A platform and drive assembly are supported on the lift frame and are driven together up and down tracks on each side of the lift frame using a rotary drive, such as a hand crank or electric motor, to power the drive assembly. The drive assembly is operable by a person on or off the platform from either the upper or lower surface or traversing stairs over which the platform is moving. The drive assembly incorporates a unique overspeed braking system and a unique clutch arrangement.

Abstract: The adapter extension of subject invention provides for the coaxial extension of a plunger or rod whose effective length has become shortened by weakness or failure of a back-up spring which causes the plunger or rod to lose its effectiveness as a strut, for example, a situation that occurs primarily in nuclear reactors where the plunger engages a grid, whereas the grid provides lateral support to the upper end of the dry tube. The adapter is thimble-like and fits tightly over the end of the plunger that engages the grid. The adapter contains a spring which has the effect of substituting for or supplementing the original spring behind or below the plunger. The body of the adapter includes a retainer for holding the interior spring captive during assembly and operation of the adapter.