Document ppXqLvQzmv84en6JK5qednwX7

COLD FORMING OF METALS Fig. 23*27: This magazine on a push feed enobles the operator to catch every press stroke Slot "A" in the pusher must be in alignment with interlock "B" before the press can be tripped This feature assures proper positioning of the port in the die Figures courtesy Liberty Mutual Insurance Company blanks or pieces are fed, one at a time, by a mechanical plunger or other device which pushes them under the slide Manually operated plunger feeds are used for individual pieces which, because of their irregular shape, will not stack in a maga zine or will not slide easily down a gravity chute Each piece is placed in the nest in the pusher and moved to the die by manual operation of the pusher. To get correct lo cation of the part in the die, an interlock is sometimes necessary so that the press can not be operated until the pusher has spotted the part accurately (Fig 23-28) SUde or push feeds are a variation of the chute feed, combined with magazines and plungers The pieces are stacked in the magazine As each piece reaches the bot tom, it is pushed into the die by means of a hand operated plunger (Fig 23-27) Sliding dies are pulled toward the opera tor for safe feeding and then pushed into position under the slide (ram) for the downward stroke The die may be moved m and out by hand or by means of a foot lever Regardless of how the die is actu ated, it should be interlocked with the press to prevent tripping when the die is out of alignment with the slide (Fig 23-28), and "stops" should be provided to prevent the die from being inadvertently pulled out of the slides Dud feeds consist of two or more nests arranged in dial form The dial revolves with each stroke of the press, so that the operator can feed the machine safely The part to be processed is placed in a nest on the dial which is positioned in front of the die The dial is indexed with each up stroke of the press to deliver the next nested part into the die (Figs 23-29 and -30) 23-25