Spring-Loaded LVDT Linear Position Sensors
April 1, 2016
Pneumatic cylinders employ linear variable displacement transducers (LVDTs) to measure range of motion. Macro Sensors offers the BBP series of air extended, spring-loaded LVDT position sensors. The position sensor features a 3/8" diameter pencil-type gauging probe that moves out and takes measurements only near the very end of the probe movement, when it is almost fully extended, and then retracts so the probe gets out of the way of incoming parts. In this way, a short range LVDT linear position sensor (0.050" to 0.125") can provide high resolution since the full range of the cylinder stroke often does not have to be measured.
"Many users do not want to measure the total range of the cylinder; they just need to get the probe out of the way of damage," said a company spokesperson. In these applications, a 1" or 2" stroke cylinder can use a short range spring-loaded LVDT to measure a nominal +/-1 mm at full probe extension. The cylinder then retracts the ram and gauging tip.
In addition to pneumatic cylinders, Macro Sensors' BBP family of pencil-type gauging probes is designed to provide precise dimension measurement in a variety of QC, SPC and industrial metrology applications. Sensors utilize a linear ball bearing assembly fitted to a hardened and ground non-rotating probe shaft to minimize radial play and the effects of side loading. This results in probe repeatability of 0.000006" (0.15 µm).
The other end of the shaft is internally threaded to accept an interchangeable tungsten carbide contact tip designed for wear resistance and reliability. During measurement cycles, the shaft is extended by means of a low-pressure (10-30 PSI), clean, dry air supply, with a regulated flow, through a barbed fitting on the end of the unit for 1/8" I.D. hose. With the release of pressure, an internal spring returns the probe to its normal position. The entire bearing, shaft and LVDT assembly are enclosed in a 3/8" diameter stainless steel tubular housing.
BBP units are available in three standard ranges: +/-0.040" (+/-1.0 mm), +/-0.100" (+/-2.5 mm) and +/-0.200" (+/-5.0 mm). Gauging probes are available in a 3/8" diameter plain housing or partially threaded with industry standard 3/8-40 UNS thread.
For more information contact:
Eileen Otto
Macro Sensors
7300 US Route 130 North
Building 22
Pennsauken, NJ 07828
856-662-8000
positionsensors@macrosensors.com
www.macrosensors.com
< back