A test fixture for circuit cards comprising a probe board bearing electrical test probes in a fixed position with respect to the overlying test surface. A flexible sheet is supported by the probes and serves to stabilize their relative positions. The circuit card is held against the probes by vacuum...http://www.google.se/patents/US4164704?utm_source=gb-gplus-sharePatent US4164704 - Plural probe circuit card fixture using a vacuum collapsed membrane to hold the card against the probes
