Instead of multiple load cells or a single cell and flexures, one dual or triple beam cantilever load cell is located centrally and the platform is secured directly to the top of the load cell
A new concept in single point load cells is set to bring significant changes to the design of low capacity weighing equipment.
The CPB aluminium planar beam from Flintec overcomes important design criteria which have hitherto not been addressed by load cell manufacturers.
The single point (or moment insensitive) load cell has been around for more than 30 years and is now well proven and accepted for use in bench scales, counting scales, postal scales, retail scales, checkout scales, medical scales, hopper scales, belt weighers - the list goes on.
Their design offers simpler scale design, elimination of flexures, high performance, wide range of capacities, low cost, and good environmental protection.
The principle of operation is very simple.
Instead of using multiple load cells (one at each corner) or a single load cell and flexures, one dual or triple beam cantilever load cell is located centrally in the scale and the platform or weighing structure is secured directly to the top of the load cell.
The design of this type of load cell resists torsional loads created by the load being placed off centre. During manufacture, the flexures are manually adjusted by filing or grinding, in such a a way that wherever a load is placed on the platform, the output from the load cell remains the same. Although the single point was originally designed for low capacity scales in relatively clean environments, developments in sealing technology, material of construction, and capacity range have significantly extended the use of this product.
Fully weld sealed IP68 stainless steel single point load cells up to 1000kg capacity are now available which can accommodate platform sizes of 1000 x 1000mm.
However,despite the developments in these areas, two important design criteria have, until now, eluded manufacturers.
Low capacity single points typically suffer from poor side to side stability and offer only a narrow mounting surface for the platform.
The flexures themselves are very thin, making the units susceptible to mechanical damage.
In parallel, attempts to design low profile products have floundered around a height of 20mm.
The design of the Flintec CPB not only provides an extremely low profile - down to less than 8mm for the 3-15kg versions - but also offers a very wide mounting surface.
The CPB has two flexures in the same horizontal plane, rather than above each other in the vertical plane.
The mounting surfaces between these flexures measure approximately 60 x 65mm and have four, rather than the customary two, fixing holes.
This provides a very stable base for fixing platforms, small hoppers, conveyors or other structures.
Even in the 3kg version, the CPB flexures give excellent mechanical strength and excellent side to side rigidity, allowing platform sizes of up to 350 x 350mm to be used.
These design criteria make the CPB particularly suitable for low profile bench scales, checkout scales, baby scales and postal scales, as well as small hopper scales and filling machines.
