Patent GB-1337171-A (GB)
Title: Method and apparatus for compacting granular material
Inventor: HURLEY DONALD L
IPC: B22F3/03
Filed: 1971-04-23
Abstract: 1337171 Compression-moulding granular material MINSTER MACHINE CO 23 April 1971 [28 May 1970] 11087/71 Heading B5A A mechanical press for compacting granular material, e.g. powdered metal or ceramic, which may subsequently be sintered or cured and sized or trimmed, has a fixed stroke reciprocating mechanism driven by a timed cam shaft arrangement (Fig. 3, not shown) and including upper and lower punches which cooperate with a die and core to define a die cavity, the die being carried by a movable die table which has three dwell positions; an upper in which ejection of the compacted workpiece takes place, an intermediate in which filling is effected, and a lower in which the powder is compacted. Two crank throws 58 effect reciprocation of the lower punch 150 and movable die table 74 whilst an intermediate throw 56, trailing at 75 degrees, reciprocates the upper punch 152. Downward movement of the rods 64 lowers a bridge member 70, so that it no longer supports the weight of the die table and the lower punch 150 with its support 78 and 148. This weight is thus taken by the plate 82 supported from cushions 94, which collapse until the rods 84 come to rest upon rods 86, which arrest further movement of both the die table and the core 168 to which it is connected via rod 103, plate 162 and rod 166. Continued downward movement of rods 64 and bridge 70 causes the pins 92 to press upon the plate 88, and this effects further collapse of cushions 94 and draws down the lower punch support 78 until its shoulders 190 come to rest solidly into the member 192, which is mounted on a fixed bed flange 72. The lower punch 150 is thus drawn down within the die 146 to create a cavity, which fills with granular material from a shoe 20 which has been moved into position, and has removed the previously compacted workpiece 151, by a piston and link mechanism 111, 112 and 116 incorporating a lost motion device and operated by an adjustable or replaceable cam on the slide 22 carrying the upper punch (Fig. 5 and 6, not shown). The bridge 70 continues downward movement, this over-travel being permitted by compression of cushions 90. Meanwhile the upper punch moves downward, the filled shoe 20 being withdrawn by the slide cam, and the punch entering the die cavity to begin compaction. The frictional engagement, of the material being compacted, with the die table 74 moves this down causing the cushions 88 to yield until a lowermost dwell position is reached and compaction is completed. At the bottom dead centre position of the top punch the bridge 70 is moving upward and thereafter engages the lower punch support 78 to raise the punch; the die table 74 and core 168 being also restored to their uppermost positions by removal of downward pressure on the plate 156. Continued upward movement o the lower punch ejects the compacted workpiece. The position of the die table on the support rods and hence its movement can be adjusted by rotation of nuts into which they screw, this rotation being effected in unison by a gear mechanism (Fig. 7, not shown). Various arrangements of core positions and movements relative to the die can be effected by adjustments of nuts 81, 83, 164 and 184 to obtain different spacings between floating plates 162 and 174 relative to fixed plates 32 and 184, and also by pressurizing the diaphragms 170, 172 or 178. In a variation (Figs. 21 and 22, not shown) a lower floating die table is provided, this carrying an outer punch which is coaxial with the first lower punch so that a flanged workpiece will be ejected in two stages during the upward ejection stroke.