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Trackballs, in general, are particularly suitable for precisely positioning a cursor on a display screen. They are often preferred to a mouse, for professional applications, because they are not vulnerable to cable damage and do not require a large clean surface on which to operate.
In many trackballs the shafts of the encoders used to sense rotation are also used as two of the three supports for the ball. This design brings benefits in terms of cost and size but, inevitably, trackballs using it have some shortcomings. They are vulnerable to damage because any shock applied to the ball is transmitted to the encoders. The use of inflexible suspension points means that, if the trackball is mounted at an angle, or is subjected to vibration, the contact between ball and encoder can be broken, thereby stopping meaningful electrical output. As the direction of rotation of the ball can never simultaneously be in the same direction as the rotation of both encoder shafts, the smooth operation of the ball is affected. This characteristic also introduces a bias to the ball's rotation.
In Daco trackballs ball rotation is sensed by two high-quality optical encoders that contact the ball via a soft polyurethane foam roller chosen for its resistance to compression set, flame and corrosion. The foams flexibility allows it to "ride over" any small particulate contamination that may cause encoders on other trackballs to jam. The flexibility also ensures that contact between the ball and the encoders is maintained even if the trackball is mounted at an angle or is subjected to heavy vibration. The encoders themselves have been purpose designed for the application. They have very low friction and inertia and so have minimum effect on the "feel" of the trackball's operation. The ball itself is supported by 6 stainless steel ball bearings that are free to rotate, in any direction, in a polymer bearing. This means that direction of operation is never biased. The design also ensures that any excessive force applied to the ball is transmitted through the lower polymer bearing, into the robust housing holding it, thereby avoiding damage to the encoders. The result is a trackball that provides a high reliability, cost effective solution for professional applications. |
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Daco Scientific Limited, Vulcan House, Calleva Industrial Park,Aldermaston, Berkshire, RG7 8PB, UK. |
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Industrial Joysticks :: Military Joysticks :: Trackballs :: Control Grip Manufacturer |
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Daco trackballs in particular have the added benefits of being extremely robust whilst providing an
exceptionally smooth, free, linear action. These characteristics are the results of a design aimed at producing a "professional" quality device.
The design used to produce Daco trackballs overcomes these problems by separating the
functions of supporting the ball and sensing its rotation, allowing both to be optimised.