Probe and method for electrically contacting surfaces with protective coatings

摘要

Improvements in electrical test probes. The problem with known probes is that degree of penetration into a material being tested is inconsistent and complete penetration of protective coatings is not reliably achieved. The device and method of the invention provide consistent and reliable penetration and electrical contact. Probe assembly (30) includes a probe tip (44) for penetrating a protective coating (4). An off-center punch (42) transmits an axially outward impact force of a predetermined magnitude to tip (44) when tip (44) is urged against coating (4) to move tip (44) axially inwardly against the force of springs (56, 74). The force compressing spring (56) is suddenly released to allow spring (56) to apply an abrupt impact force to tip (44). The degree of impact and penetration may be adjusted for different coating thicknesses by adjusting the stiffness of spring (56).