Vertical Platform (Wheelchair) Lifts Expert Article

Vertical Platform Lifts (VPLs) are the industry term for what are more colloquially referred to as wheelchair lifts. Despite the shorthand, VPLs are designed to accommodate users with or without the use of a wheelchair and commonly have a maximum capacity of 750 lbs.

In this article, elevator expert and industry veteran Dan Short discusses VPL failures that can result in injuries. His discussion includes some of the recommended maintenance, testing, and inspection requirements that are relevant to forensic investigations.

Vertical Platform (Wheelchair) Lift Hazards

Compared to an elevator, VPLs are a more economical way to provide access across multiple floors or vertical heights that can’t be practically accommodated with a ramp. Common applications include homes, churches, and other public buildings with accessibility requirements but a limited footprint for installation.

While VPLs are slow-moving when compared to elevators, they can be prone to pinch point, crush, and tripping hazards.

VPL System Failures

Vertical platform lifts involve a host of sensors, switches, and drive mechanisms that, if not properly functioning, can result in various system failures.

Safety Switches

Most VPLs are equipped with several safety switches to stop the operation of the lift if parameters fall outside of normal operation. The failure of a safety switch could potentially cause a failure to:

• Stop the lift reasonably flush with the floor
• Lock safety gate
• Detect obstructions below the lift platform (safety pan)
• Activate the emergency stop

Batteries

While lifts are hardwired to a power source, the controls are commonly battery powered. It is recommended that the control batteries be replaced every two years. If battery failure occurs, users would be unable to operate the lift and there would be a risk of users getting stuck between floors.

Operational Switches

VPLs are equipped with constant pressure switches, meaning that the operator must continuously apply (push) pressure to the switch of desired direction of travel to make the lift move to the intended landing.

There will be a set of switches at every landing on the outside of the lift and a set on the handrail wall on the platform itself. Over time, after continual use, the operational switches may need to be replaced to avoid possible shutdowns and inconvenience the user.

Driving Means

There are a few different types of VPL driving means. “Driving means” refers to what type of mechanism the lift is raised and lowered by. The two most common types are screw drive and roped/chain hydraulic.

• Screw drive: This assembly consists of a screw column that has a carriage attached. The shaft will screw (rotate) in a clockwise direction to achieve travel in one direction then counterclockwise for the other. These systems can be susceptible to failure caused by contaminants in the grease or rusting of the screw in harsh environments.
• Roped/Chain Hydraulic: This assembly will consist of a hydraulic jack with a cylinder/piston that has a sheave attached. The rope/chain will ride over the sheave in conjunction with the piston to lift the VPL in the up direction when hydraulic pressure is applied during operation. These systems can be susceptible to leaks in the hydraulic system which can cause the lift mechanism to malfunction.

VPL Maintenance Requirements

Codes and standards exist to promote the safety of Vertical Platform Lifts. These resources provide guidance on maintenance requirements and the testing of VPL applications.

Some of the determining factors for how often a lift should be maintained include:

1. Manufacturer’s recommendation
2. Equipment age, condition, accumulated wear, and exposure to elements
3. Design and quality of the equipment
4. Setting & usage

Standard of Care Experts for Wheelchairs & Disabled Transportation

Depending on the needs of your case, Robson Forensic has experts that can opine on the standards of care which apply to wheelchair fitting and selection, ambulettes and wheelchair vans, home care, and other areas relevant to cases involving wheelchair users. Visit our Health Care practice page for additional resources.

Elevator Injury Investigations

The Elevator and Escalator experts at Robson Forensic have the necessary training, education and experience to investigate a broad range of mishaps involving elevators, escalators and other forms of vertical transportation equipment encompassed under the A17.1 and associated Safety Codes.

For more information, submit an inquiry or call us at 800.813.6736.

Featured Expert

Dan L. Short, Jr., CEI

Elevator & Escalator Expert

Dan Short is an elevator and escalator expert with over 25 years of industry experience as a mechanic, maintenance supervisor, and operations manager. His expertise extends to all aspects of the… read more.