that the shaft 40 is in a position or state wherein the bar 26 is in the locked or engaged position with plate 32 in this position as depicted in fig1 the cam 38 which is eccentrically mounted on the shaft 40 effectively is positioned as shown in fig6 to release from surface 36 so that a biasing spring 70 associated with an upper lever arm 30 for the lock bars 24 26 will cause the arms 28 30 and therefore the lock bars 24 26 to rotate to the locked position in order to disengage the lock bar 26 from latch plate 32 a signal is again provided through the control circuitry and power source 56 this causes the motor 42 to rotate shaft 40 so as to align the arm 66 with the sensor 68 as depicted in fig1 this 180 u00b0 rotation causes the cam 38 to rotate against the cam surface 36 pivoting the lever arm 28 to the position shown in fig7 causing bar 26 to release latch plate 32 of drawer 20 a key operated manual override is provided to permit operation of the unlocking mechanism specifically a key operated cylinder 80 may be rotated to thereby rotate a shaft 82 mounted in the housing 10 rotation of the shaft 82 causes a cam member 84 on shaft 82 to engage against the cam surface 36 of the lever arm 28 this will cause the lever arm 28 to pivot the locking bar 26 out of engagement with the latch plate 32 in this manner a manual.