LVDT & Half Bridge Analogue Gauging Probes

Spring Push, Pneumatic Push or Vacuum Retract Gauging Probes In a conventional 'pencil probe' the tip pushes outwards under the influence of an internal spring. When installed in a fixture some mechanism must be designed to bring the probe into contact with the piece part being gauged. (Note: side loads should be avoided, especially when sub micron performance is expected over many years of use.) Pneumatic operation (pneumatic push or vacuum retract ) is a cost effective way of achieving probe movement, particularly when a large number of probes have to be actuated simultaneously. Probe types AX5/1/P and AX5/1/V have an extended movement of 9mm before entering the measurement range of ±1mm. Special Application Probes When space is at a premium the extremely compact dimensions of the AX/0.25 and AX/0.5 can be exploited whilst retaining standard 8mm diameter fixings. When it is required to stack a number of probes close to each other, the A6G/1.0 is only 6mm in diameter, but still incorporates a precision linear ball bearing. Environmental Protection A6G/1.0 and AX Series Probes are all fitted with Viton gaiters to exclude moisture and dust. Viton is chemically inert and does not degrade when subjected to cutting fluids. Gauging probes in the Feather Touch range (AT Series) have glands instead of gaiters, and therefore should only be used in a dry environment. Feather Touch Gauging Probes Feather Touch probes have been designed especially to gauge delicate surfaces and are ideal for products such as car windscreens, TV tubes, pharmaceutical bottles, electronic components etc. Whereas a traditional probe exerts a tip force of approximately 70 grams, the Feather Touch probe is a mere 18 grams when used in the horizontal position. This reduction is achieved by replacing the naturally elastic traditional gaiter with a close tolerance gland. On pneumatic versions the air leakage through the gland is restricted to less than 6.0 millilitres per second at 1 bar to minimise the possibility of contamination to the surface being gauged. Despite the low volume of air flow the bearing within the probe is constantly purged, avoiding the build up of dust (use of filtered air is recommended). Replaceable Nylon tips are used to guard against surface damage, although for measuring hot glass Tungsten Carbide tips can be fitted. Woven steel braid covering on the cable provides additional protection for applications where down time is critical. For the ultimate low force, Feather Touch probes can be supplied with no spring at all (Suffix---/F). Forward and return strokes are activated by pneumatic push /vacuum retract, but adjustment of air pressure allows all probes to have identical tip force, constant over the entire stroke. If the probe is mounted vertically (tip at the top), retraction is by the dead weight of the moving parts, eliminating the need for vacuum.

For more information on LVDT & Half Bridge Analogue Gauging Probes talk to Solartron Metrology Ltd