Automatic Tipping and Stacking

About

The limitations of the design are assumed to be as follows: 1. The floor plan cannot be overhauled, e.g. there would be no extensive renovations to install things like conveyors. 2. The mail trays cannot be redesigned due to operational limitations. 3. The mail packages cannot be redesigned due to the same reasons. 4. The trolley with the mail trays must be in front of the sorting machine due to retention of floor planning. Thus, the method that is described must involve a rig that is set in between the trolley and the sorting machine. (See the attached images for illustration.) The rig has a set of arms; these arms are mounted on a rotary turret and can move slightly apart from each other, so that the arms can go around a mail tray (see Figure 1). The arms can then close towards each other to grip the bottom edges of a mail tray. Figure 1 has omitted a tray that is mounted on top of the turret, for the purpose of displaying the gripping process. The tray, henceforth referred to as the "rig tray" is mounted atop the turret, with enough clearance for the mail tray to be gripped; see Figure 2. Thus, when the mail tray has been gripped, the rig tray is atop the mail tray. The rig tray has a flap, with an electromagnet lock; this will be of significance in a later step. When the turret with the arms grips a mail tray, the rig tray should be cupped over the mail tray; hence, the rig tray has to be slightly larger than the mail tray. See Figure 3 for illustration. The turret then rotates, thus tipping the contents of the mail tray onto the rig tray. This is shown in Figure 4. After that, the rig approaches the sorting machine, as shown in Figure 5(a). The rig then tilts, so that the packages slide and stack against the flap with the latch. The latch releases, thus opening the flap. The mail packages then slides out of the rig tray and onto the table of the sorting machine. The angle of the tilt and the time that the rig tray lingers have to be calibrated to ensure that all of the mail packages slide out. (Alternatively, a load gauge can be used to detect whether the rig tray's weight has returned to the weight when it was empty.) The rig then moves away from the sorting machine for a short distance. A powered hinge on the rig tray closes the flap. The rig then moves back towards the sorting machine, using the wall of the flap to push the mail stack flush against the table wall of the sorting machine; see Figure 6. The rig then moves away from the sorting machine and rotates to its initial orientation (or vice versa, if this is more convenient). The rig then moves over to the receptacle that would receive the empty mail tray. The rig releases the empty mail tray onto the receptacle, and returns to its initial position. The process then repeats, after a waiting time as determined by the speed of the sorting machine.