1. Field of the Invention
The present invention relates to key duplication equipment, and more particularly, to a key positioning fixture for positioning a master key and key blank relative to each other and relative to a key follower and key cutter of a key cutting machine.
2. Description of the Prior Art
Use of a conventional key cutting machine having a mechanical key follower and a rotating cutter wheel to duplicate single-sided keys which include a bitted surface on only one side of the key blade produces relatively predictable results. In such single-sided key duplicating operations, the linear root or base surface of a master key and a key blank may be easily aligned with a corresponding linear base surface of a vice-like key clamping device on a relatively repeatable basis may be used to accurately achieve the necessary vertical, lateral (or horizontal) and angular (tilt) alignment between a single-sided master key and a single-sided key blank to yield an operable duplicate key. As a result, the frequency of single-sided key miscuts resulting from the use of conventional key positioning fixtures is acceptably low.
Using key positioning fixtures available on conventional key cutting machines to duplicate double-sided keys has historically resulted in unacceptably high miscut rates. Double-sided keys are symmetrical with respect to the key longitudinal axis and are typically used for automotive applications. The original or master copy of a double-sided key which is provided by the original equipment manufacturer to the original automobile purchaser is typically mass-produced on high speed, high cost code-based keel duplication systems which yield keys with high precision mirror image bit notch patterns on the opposing, parallel-oriented sides of the key blade.
The low cost, mass-produced key cutting equipment typically used by locksmiths, discount stores, hardware stores and related mass-merchandising outlets while functioning adequately to reproduce single-sided keys, experience severe problems in maintaining the necessary critically accurate alignment between the master key to be duplicated and an uncut double-sided key blank. Alignment errors result from the fact that a key cutting machine operator must use trial and error techniques to properly secure both the double-sided master key and the double-sided key blank in their respective key clamping vices to achieve the necessary vertical, lateral and tilt alignment between the two keys by using the flat, horizontal base surface of the key clamping vices. Because both sides of a double-sided master key blade include an undulating bit notch pattern, the necessary critically accurate alignment between the master key and the key clamping vice cannot be reliably achieved.
A second source of alignment error arises when the key cutting machine operator removes from the key clamping vices both double-sided master key and the double-sided key blank and invents both keys to allow the second side of the double-sided master key to be duplicated on the key blank. Once again the operator through a trial and error process must establish the critical up/down, left-right and tilt alignment between the double-sided master key and key blank. Because now even the lower "reference" surface of the partially cut double-sided, key blank includes an undulating bit notch pattern, the problem of achieving the necessary multiple axis alignment between the master key and the key blank has been rendered even more serious.
Because of the number of variables involved in performing the side one key duplication process followed by the side two key duplication process, both of which require that precision alignment be achieved between the master key and key blank, the use of conventional key cutting equipment to duplicate double-sided keys has resulted in unacceptably high miscut rates and correspondingly high customer dissatisfaction.