The 'Digital Micro-probe' measures the resistance to penetration of a one-millimetre diameter wire probe. The information is transmitted in ASCI text format and can readily be viewed and manipulated in an Excel spreadsheet.
There were two major elements to the mechanical design:
1) Probe support.
Being only one millimetre in diameter, and up to one metre long, the flexible probe needs to be supported when not in the timber. Early telescopic solutions were fraught with problems in terms of both the complexity of servicing and the inability to cope in an often-dirty environment.
The bold step was taken to invent a 'three dimensional zip' support. When together, the two halves of the zip sandwich the probe and interlock to form a rigid beam. When separated, the zip halves are flexible enough to bend around the body of the instrument.
This had the benefits of a huge reduction in maintenance costs; the ability to use any length of probe; and, not least, a point of interest that continually draws customers in and engenders faith in the product.
2) Drive mechanism.
The drive mechanism was complicated by a need to allow a small amount of lateral movement in order to measure the pushing force on the probe.
We took advantage of this lateral movement by extending it, and incorporating an automated 'chuck' for the probe. This had the benefit of reducing the opportunity for damage through miss handling, and greatly reducing the complexity of probe manufacture.
As always, there was a relentless regime of model making, prototyping and testing throughout the design process. Here is just a sample.