Model 4640 The main difference between the Model 4640 Articulator and traditional Whip Mix articulators is the elimination of the crossbar between the uprights on the lower member. This frame design provides optimum posterior access for enhanced visibility and lingual access of any Whip Mix articulator. Features Tracking fossae which allow upper and lower frames to remain together during excursive movements Durable Delrin® condyle elements which provide silky-smooth condylar movements “Accumount” System of Interchangeability which allow accurate interchanging of casts between articulators Fully open access from the lingual position for easy access during denture setup Easy to operate Locking Mechanism provides the following actions: Allows removal of upper frame from lower frame for cleaning and servicing the articulator In the locked position it provides a quick way to return to centric position and locks the articulator for added stability In the mid-range position the Locking Mechanism allows the condylar ball to move freely down the track of the condyles during excursive movements A Support Rod to support the upper frame of the articulator when open A built-in storage compartment for storing the support rod when not being used Condylar guidance featuring: Adjustable condylar inclination Progressive side shift Fixed intercondylar distance of 110 mm