The benefits of linear-based lifting columns
Linear lifting columns are able to offer a range of key design benefits in a variety of ergonomically-focused applications – from medical equipment such as patient beds to industrial uses such as trolleys for automated production lines. Indeed, wherever there is a need for an adjustable lifting mechanism, there is a need for this technology.
The advantages of lifting columns are their combination of adjustability, small footprint, low noise and rapid, but steady speed.
Thomson Industries, a part Danaher Corporation North America, recently introduced its LC range of linear lifting columns recently introduced its LC range of linear lifting columns, which are finding use in a range of domestic, medical, and workplace applications. Kyle Thompson, the company's product line manager, explains the principles: "A lifting column is a package with both a lifting mechanism and bearing supports built into one," he says. "So you have a lifting mechanism with the actuator inside it and telescopic aluminium extrusions. Between those extrusions you have engineered polymer bushings that provide load support. So essentially, you have both your lift mechanism and your moment load support for side-to-side movement."
However, the telescopic action of the lifting columns is their key benefit, allowing as they do the adjustable lifting of a range of loads. Clearly, this relies on them being able to offer a considerable extension to retraction ratio – in other words, the ability to move smoothly and rapidly from very low to very high. In the case of Thomson's LC series, this is achieved by the use of a mechanically-actuated 25mm diameter lead screw within the tube that is supplemented by another, 12mm dia. lead screw to provide additional lift.
With the actuator are internal limit switches wired within the motor. These are wired in such a way as to ensure that, when the actuator hits the end of stroke, it will automatically turn itself off. It will not let it go any further or cause any damage to the motor or the end of the unit. In addition, at the bottom of the tube there is a wrap spring brake, which holds the load when the power is off. Thus, should the power go down for any reason, the workstation or medical table bed will hold its position.
Thomson Lifting Columns are available in three model variations (LC1600, LC2000 and LC 3000, which provide different performance in extension to retraction ratio, load capacity, speed and cost to best match application needs. As with all Thomson solutions, the lifting columns can also be customised to meet specific customer requirements.
Depending on the application, multiple lifting columns may be required, which can be synchronised via a Thomson control unit to ensure they work perfectly in unison. One such application is in medical tables such as those used in hospitals for examination, where the ability to get onto and off of the table easily is important – particularly as those doing so may be physically incapacitated. In such applications, there is of course no guarantee that the overall load will be balanced, which is why Thomson offers a demonstration desk lift that they can load with two 5 gallon water bottles at one end to demonstrate the ability of the lifting columns to deal with offset loads.
One application of the lifting columns has been in the Meyra Champ adjustable height wheelchair, where the ability to lift the user safely, smoothly and reliably is clearly vital in order to ensure safety, comfort and stability. Here, the lifting column allows the wheelchair user to sit comfortably at eye level with companions with ease.
In industry, lifting columns have been used to create adjustable trolleys or materials handling equipment, meaning that employees of greatly differing heights are able to lift and handle items without bending or reaching in such a way that could potentially threaten their wellbeing (and perhaps lead to claims against their employers).
