These GTH contacts will be described further in this paper; but first let us examine the connector system in more detail against the basic requirements previously established.
The system provides a modified zero insertion force connector with the following features and benefits:
A. EASE OF USE: Since insertion is straight-in, and actuation is simultaneous with insertion without requiring a separate action; insertion force is essentially independent of contact force and the number of contacts, and is predetermined by the return springs; removal is automatic by depressing an eject bar.
B. PROTECTION FROM ABUSE is inherent in the design since the connector is recessed deeply in the console behind a protective door; the p.c. board pads are behind a protective door; the connector cannot be in an actuated position when the cartridge is inserted; and the cartridge cannot be inserted upside down. If the locking device is overcome by pulling hard on the cartridge, no damage occurs and the connector returns to its proper position. To withstand insertion forces the connector was molded of a strong glass filled thermoplastic polyester material.
C. PROPER ALIGNMENT is assured by a key in the connector and a slot in the p.c. board, both with generous lead-in chamfers.
D. ELECTRICAL STABILITY is achieved by utilizing a gold alloy inlay material for the contact surface of the spring, and by maintaining adequate contact normal forces.
E. MANY MATING CYCLES are obtained from the rotating zero insertion force type action which minimizes wear by creating a very short wipe distance of the contact springs; low, well controlled contact forces; use of a relatively hard gold alloy inlay material on the contact spring; and a fine grain phosphor bronze spring material to prevent fatigue.
F. LOW COSTS are realized by using a gold alloy inlay to minimize gold usage on the contact spring; tin alloy plating for the GTH contact end of the spring that connects the flat cable; fast molding thermoplastic polyester material for the connector housing; and a design that permits automatic machine assembly of the contacts into the housing.
System installed costs were kept low by providing GTH connections to the flat cable which require only a simple push type insertion, as opposed to other designs which require soldering of discrete wires. The separable GTH contacts also permit easy removal of the connector from the console without desoldering, should replacement be necessary.
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