The lift in the Piigaste Südamekodu nursing home in Põlvamaa, which fell in early February causing leg fractures to two staff members, fell due to the wear of critical parts, reports Lõuna-Eesti Postimees.
"The fall of the platform lift was made possible due to significant wear of the thread of the drive and control nuts, which allowed the platform to slip off the screw mechanism," said Reino Bürkland, an expert from the technical department of the Consumer Protection and Technical Regulatory Authority (TTJA).
The expert explained that the building of the nursing home is equipped with a platform lift with a screw mechanism, rather than a traditional cable lift. While a regular lift is raised and lowered by a cable from which it is suspended, a screw lift operates on a different principle. It is equipped with an electric motor that drives a nut rotating around a long lead screw. Essentially, it works like a nut that rotates on a bolt.
"The nut on the lead screw provides self-locking. But if it is worn out, the self-locking does not work, and the platform simply slips down the screw. However, there are not one, but two nuts on the screw: the drive nut and the control nut. The distance between them indicates the degree of wear," Bürkland explained.
The thread on both nuts was worn out, and a third safety system was not provided. The nut of the lift, that is, its drive nut, in the Piigaste nursing home was worn out, which caused the lift to fall.
On February 3, three caregivers from Piigaste Südamekodu were using the lift to go to the upper floor to change the residents' diapers. The lift fell with them several floors down, resulting in two of them suffering leg fractures.
