MAGNETIC LINKAGE FOR BOURDON TUBE GAUGES

摘要

A Bourdon tube (20) pressure gauge (10) has a movement amplifying mechanism (32) comprising a pinion (30) of segment (25) shaped permanent bar magnets (29a) extending radially and terminating at a circular edge magnetically driven by a pivotally mounted rack segment (25) having an arcuate band (29) of permanent bar magnets (29a) arranged in parallel alignment with polar axes extending radially of the rack and transversely of the band (29). One of the poles of each of the magnets (29a) of the band (29) is located along a driving arcuate edge thereof which faces and magnetically drives the circular edge of the pinion (30) by magnetic attraction of opposite poles. The polarity of adjacent magnets (29a) on both the pinion (30) and rack segment (25) is reversed providing alternate N and S Poles around the pinion (30) circular edge and along the driving edge of (29) the band (29), respectively. In one form of movement, the rack segment (25) is formed with an opening and the driving arcuate edge faces the opening in which the pinion (30) is positioned for operative magnetic engagement between the band (29) and pinion (30). In another form of movement, the pinion (30) is positioned radially beyond the rack segment (25). The movement is housed in a rear compartment of the gauge (10) which is lined with a magnetic flux barrier material.