Motor Types
There are two main motor types which are suited for the patient handling industry. Permanent Magnet DC Motors and Brushless DC Motors.
Permanent Magnet DC Motors (PMDC) are ideal for this industry because they have a high starting torque, which is perfect for applications which must manage a high load. Additionally, they are more cost effective than Brushless DC or AC alternatives.
An alternative to the PMDC motor is the Brushless DC Motor (BLDC) which has a much longer service life as it does not contain brushes which can require more maintenance due to carbon brush wear limiting the life expectancy of the motor. They are more expensive than brushed motors, but if the application is continually used or requires high levels of precision the extra investment will be worth it over the life cycle of the motor.
Gearbox Options
These motors can be paired with a variety of gearboxes, depending on the specific requirements of the final application. There are three main options: the worm wheel, the spur, or planetary gearbox.
The worm wheel gearboxes are not as energy efficient as other solutions, but they boast a straightforward design and are ideal for applications which require the output shaft to be placed at 90 degrees to the motor whilst remaining cost efficient.
The spur gearbox, on the other hand, is compact and efficient with a high starting torque and the complex design means they are less cost efficient. However, they are noisy when operating at high speeds, and they have higher levels of wear and tear than other gearbox types.
The planetary gearbox has a very high torque due to its structure where multiple gears share the load. They also fit within a compact size envelope and inline drive which makes them ideal for applications where space is at a premium.
A worm wheel gearbox and planetary gearbox can also be combined to create a right-angle drive with very high torque density. This is often selected due to space limitations.
Stairlifts
Stairlifts can be a vital component in enabling someone with mobility issues to stay within their own home, by making transportation up and down stairs safe and reliable. To achieve this, stairlifts need to be able to manage varying loads at the same time as maintaining a smooth ride along straight or curved rails.
Stairlifts have four main requirements:
- Smooth acceleration and braking
- Quiet operation
- Compact integration within rail and carriage systems
- Long service life with minimal maintenance
These are all as standard with the Parvalux range of suitable geared motors. Parvalux would recommend the PM90-GB65 for stairlifts in order to deliver high torque at a controlled speed for consistent stairlift movement in a location where space is an important consideration.
The seat levelling drive, which ensures the seat remains level throughout the travel journey, particularly on curved rails, also requires a gear and motor and the BRx53-30-GB56 is an ideal option for this.
If the application features a retractable rail mechanism, then the PM8-GB36 is the most appropriate solution, as it enables sections of the rail to be moved when not in use which is ideal for smaller domestic spaces ensuring the rails do not obscure hallways or doorways.
Patient Hoists
Patient hoists are vital pieces of equipment within both a clinical and residential setting. Regardless of whether they are mobile or ceiling mounted, they require accurate lifting and positioning under varying loads, as well as maintaining smooth and controlled movements throughout the entire process including start/stop cycles.
This, therefore, means that the geared motor powering the hoist needs to provide:
- High torque at low speeds for controlled lifting
- Smooth motion to enhance patient comfort
- Robust construction for repeated use
- Simple integration with internal or external pinion systems
Parvalux have designed and manufactured the PM90-GB14 which is well-suited for ceiling mounted patient hoists. It is designed specifically for overhead track systems, and ensures a smooth, controlled movement with high positional accuracy.
A brake and encoder are often also selected to provide additional safety and feedback control.
Powered Wheelchairs
Powered wheelchairs are vital for people with mobility issues as they offer independence over a variety of terrains. In order to deliver this, they require responsive, efficient drive systems that deliver both manoeuvrability and endurance.
All powered wheelchairs, whether for adults or children must be able to deliver:
- High efficiency to maximise battery life
- Smooth and responsive control for user safety
- Compact and lightweight design
- Reliability across diverse operating conditions
For standard use and children’s wheelchairs, the BRx70-GB12 combination offers a compact and efficient solution ensuring there is the requisite power, as well as battery efficiency.
Heavy duty wheelchairs on the other hand, would be better served by the PM90-GB9 which is better able to manage heavier load capacities, by being able to produce the torque required to operate them smoothly, safely and consistently.
A brake with a manual level is often selected to provide additional safety when stationary.
