Worn roller guides likely the cause of minor elevator injury

Incident overview

Elevator passed bottom landing and made contact with pit buffers.

Regulated industry sector

Elevating devices - Elevator

Location

Burnaby

Investigation conclusions

Site, system and components

The elevator travels up and down the hoistway guided by rollers along a T-bar rail system. This keeps the elevator aligned and allows the elevator to ride more smoothly. This vintage of elevator has a slowdown switch that contains normally closed electric contacts which open when the elevator reaches the top or bottom landings. This slow down switch is mounted to the elevator cab and is activated by a fixed cam mounted at the top and bottom of the elevator hoistway. As the elevator reaches the top or bottom landing the activation of the slowdown switch, slows down the elevator before stopping and opening the doors.

Failure scenario(s)

Elevator roller guides were found worn beyond tolerance and thereafter past their serviceable life. The elevator travelled out of alignment and therefore the slowdown switch did not make contact with the fixed car causing elevator to pass the floor coming into contact with buffers at a reduced speed.

Facts and evidence

On-site investigation:

• The slowdown switch on the elevator cab was in normal operating condition.
• The slowdown switch activation cam was in place at the bottom landing and top landing.
• The roller guides where found to be worn.
• As per Licenced contractor the roller guides are at the end of their operating life and had to be replaced.

Causes and contributing factors

It was highly likely that the incident occurred due to the excessive worn roller guides used to keep the elevator in alignment. The roller guides had not been replaced before being worn beyond their operating life.

Impact

• Injury
  • Qty injuries: 1
  • Injury description: Person reported that they were thoroughly jarred, frightened and shaking. Physical effects noticed later included tightness in the mouth and jaw, aching in the elbow, aching in the neck, sides and lower back.
  • Injury rating: Insignificant

Damage

• Damage description: No damage
• Damage rating: None
• Incident rating: Insignificant