and work tasks to reduce the hazards of lifting. Safety programs instructing workers in proper lifting techniques have also been implemented on a large scale.

In recent years, there has been a dramatic increase in the number of workers who rely on back belts to prevent injury during lifting. Back belts, also called "back supports" or "abdominal belts," are currently worn by workers in numerous industries, including grocery store clerks, airline baggage handlers, and warehouse workers. Some limited studies undertaken by NIOSH conclude that back belts do not do any good and in some instances they may do harm. First of all, back belts do not increase the amount of load you can lift safely because the belts have nothing to do with the back system. You can’t lift any heavier objects with or without a back belt, but a person wearing a belt may become over confident and attempt to lift a heavier object than is reasonable.

As mentioned, businesses and corporations, both large and small, have implemented programs that teach workers to lift objects properly. Most of those programs emphasize the importance of “lifting with the knees and not with the back” or else “bend the knees, not the back”. The generally accepted practice in the workplace is to then shift the stress and strain caused by heavy lifting from the back to the knees. However, the prescribed lifting techniques still give the worker no advantage in lifting heavier objects and worse yet, what happens if the worker has bad knees to begin with? There is definitely a need for a method or means to help a worker lift objects safely, and it would be more advantageous to provide a means or method that allows a worker to safely increase the weight they can lift so they can safely work below that higher limit. Figure 1 illustrates various lifting techniques currently being advocated in major safety training courses used throughout the world. The different drawings each show a different technique, but as you can see from the illustrations, every prescribed lifting technique involves bending the knees to some degree. And here’s the problem: if the knees are bent during lifting while the back remains fairly straight, then an additional lifting burden is placed on the knees because the worker’s own body weight (upper torso) must be lifted or raised by the knees along with the object to be lifted. In other words, the lifting load is increased possibly many times over the weight of the original object requiring lifting, and all of the additional stress and strain is placed on knees that are deeply bent and in a position which makes them very vulnerable to injury!

Suppose there were a means or method that captures and stores energy when the knees are bent and then uses the stored energy to assist the person when lifting a heavy object. That’s exactly what the Lift’N Ease Safety Knee Pad does! A quick review of Physics principles is in order. Work is required to raise a mass to a higher position (altitude) against the pull of gravity. The object or mass at the higher position then has acquired potential energy which can be converted to kinetic energy as the object again moves to a lower position. On the other hand, if some of the energy is stored in an elastic mechanism when the object is lowered, such as a compressed spring, then the stored energy again becomes potential energy that can be used to do work and lift the object back to a higher position. This is exactly the principle involved in a bouncing ball and it is obvious the process is not perfect, otherwise the ball would return to the same original height after each bounce. In the case of lifting, any energy saved when the knees are bent and the human torso is lowered in height can theoretically be stored and then used to assist in raising the human torso to its original height. This would mean that some (not all) of the potential energy inherent in a human torso at a certain height can be stored by an elastic mechanism when the torso moves to a lower position, and the stored energy can be used to re-elevate the torso to a higher position. A system is then possible where a worker stores energy when bending the knees and the stored energy is then used to assist in raising the worker’s body during the lifting process. Interestingly, it would be a form of “regenerative bending”! And if that’s the case, then most of what is being lifted is the weight of the object needing to be lifted and some mechanical advantage has been found to assist in lifting the additional weight of the human body! Unlike a back belt, the Lift’N Ease Safety Knee Pad (or just Lift’N Ease for short) provides a mechanical advantage that actually can make the lifting process much safer and much easier.

In Figure 2, there are two different versions of the Lift’N Ease shown that use inflexible belts for attaching above and below the front knee where the opposite ends are attached to the center of either a solid-graphite (or laminated-fiberglass) plate or a rod. Stretchable, flexible material covers the belts and plate (like a kneepad) to prevent contact between any moving parts and the skin or the clothing. The user merely slips the adjustable Lift’N Ease on quickly and easily like a sleeve over the foot (or a conventional kneepad). The second drawing in Figure 2 shows the two versions of the Lift’N Ease that have been compressed by the bending action of the knee. As the user bends the knee, the inflexible belts hold the center of the thin plate or rod in position in back of the knee or on the side of the leg, respectively, so that energy is stored in the stressed plate or rod. In the case of the plate version, the plate’s ends are then pressed against the thigh and calve as the stressed plate attempts to straighten. In the fully-stressed position, the energy stored in the stressed plate or rod may not be quite sufficient to raise the user’s body. However, when the user begins to rise with a little exertion, the stressed plate will force calf and thigh apart in order to assist the user. This gives a mechanical advantage to the user in that a good part of the user’s weight is lifted with work done by energy stored in the stressed plate. The object to be lifted can then be handled safely and a little easier!

The Lift’N Ease can be quickly and easily donned over clothing for lifting episodes and then removed with little effort when they are not needed. Some size adjustment can be done to the Lift’N Ease if Velcro ends are used on the belts to vary their length for each user. Now, there will obviously be occasions when the Lift’N Ease is being worn, but where no lifting is being done. The user simply would not want to waste time removing the Lift’N Ease each time between lifting episodes, yet the user may need to bend the knee for other purposes. Note: the Lift’N Ease will be designed not to interfere with normal walking. Figure 3 illustrates how the Lift’N Ease is “deactivated” so the rod or plate does not bend or stress to store energy when the knee is bent. That way the user can quickly and easily deactivate the Lift’N Ease when there is no need for heavy lifting. There will of course be a variety of methods and means for activating or deactivating the Lift’N Ease.

There are many conceivable methods of storing energy from bending and some of the alternative methods will obviously be much more expensive and complicated than the Lift’N Ease. Cost and complexity of the Lift’N Ease should be kept as minimal as possible. Springs, air cushions, pneumatic actuators, or hydraulic shock absorbers are possible candidates for use in the Lift’N Ease to store energy. However, it is the general concept of storing energy when the knee is bent and then doing work with the stored energy to raise the user’s body to give an actual mechanical advantage to the user when lifting heavy objects. One last note: Imagine how much human energy can be conserved on a worldwide basis if “regenerative bending” is done by everyone (see Figure 4)!