Multi-motion mechanical press

In a multi-motion powder compacting press for making a useful article from powdered metal, ceramic or other particulate material, an upper assembly comprising a frame, a driven bull gear, a crankshaft having a cam and a pitman for reciprocally operating one or more upper punches into a die cavity, an improved compacting and ejection assembly depending from the frame and having a pair of inner and outer lower rams, adjustably supported by a pair of vertically spaced pressure plates, and adjustable ejection plates for upwardly ejecting a pressed article from the die cavity. Preferably, the article to be made is a two-level article, the compaction being accomplished by dual upper rams and punches pressing against the inner and outer lower rams, and the article is ejected by the sequential upward movement of lifting means responsive to the cam and below the ejection plates to force them upwardly to first eject one level of the part with the outer punch and finally eject the other level of the part with the inner punch. Means for adjusting the amount of powder fill, the relative positions of the ejection plates and the density split of a multi-level article are disclosed.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a powder compacting press and particularly to 
such a press having multi-motion movement and wherein the pressed parts 
are ejected upwardly providing more consistency in the composition of the 
pressed metal parts at higher pressing speeds and previously attainable in 
mechanical powder presses. The press is useful for compacting metal, 
ceramic, and other particulates into useful articles, such as bushings. 
2. Brief Description of the Prior Art 
Heretofore powder presses have generally been classified as hydraulic and 
mechanical presses. The mechanical presses have been further defined by 
the number of punches for ejecting the finished part and by the direction 
of the ejection either upwardly or downwardly. Examples of single punch 
presses are disclosed in U.S. Pat. Nos. Stokes et. al. 2,389,561; Smith 
3,640,654; Claus 1,607,389; DeSantis 4,053,267; DeSantis et al. 3,822,974; 
Seelig 2,570,989 and Hall 2,867,844. Examples of dual ejection mechanical 
presses are disclosed in Hurley et al. 3,764,244; Johannigman 3,168,759; 
Hara et al. 3,635,617; Belden 3,172,156; Smith 3,337,916 and Stokes et al. 
2,499,980. Hydraulic power has been used in powder metallurgy presses both 
for pressing and/or ejection. Various types of hydraulic presses are shown 
in Carrieri 4,068,520; Hermes 3,587,136; Weidner 2,556,951; Haller 
2,640,325; Haller 3,191,232; Whipple 2,253,003; Cutler 2,338,491; Vinson 
3,414,940; Graf et al. 3,460,202 and Haller 3,492,696. Rotary presses have 
also been used, for example see Shapiro 3,677,673. 
It is well known in the art of powder pressing that it is important that 
the density split be substantially in the middle of the pressed part. In 
the case of a single level part, that is, a part having opposed planar 
surfaces, such a density split is relatively easy to obtain. In the case 
of a part having plural levels, however, such a density split is not only 
difficult to obtain but requires significant modifications to the press. 
Such modifications comprise a configuration of the punches required, the 
die table, and the means for ejecting the part. Heretofore mechanical 
powder metal compacting presses have not been altogether satisfactory from 
the standpoint of part consistency and production speed. The present 
invention provides a means for obtaining substantial part consistency even 
in dual or multi-level parts and provides high production speeds on the 
order, for example of 1100 parts per hour. The mechanical press of the 
invention will produce parts on the order of twice as fast as competitive 
hydraulic presses. 
SUMMARY OF THE INVENTION 
Briefly, the powder compacting press according to the present invention 
comprises a conventional straight side press frame including a single 
crank, bull gear-pinion drive. The frame supports a cam mounted between 
the bull gear and the frame. An upper assembly in the frame supports the 
upper punch or punches, a floating die table and a bed plate. A lower 
assembly is suspended from the bed plate and includes two lower rams, each 
of which has a permanent pressure plate and moving ejection plate. Outer 
and inner punches are mounted on the two lower rams. The outer ram is 
mounted in a floating pot to permit the outer punch to float to assist in 
splitting the part density. The outer ram can float with or independent of 
the die table. 
Two ejection plates are used. The lower ejection plate provides power for 
both plates through a set of ejection arms driven by an ejection cam on 
the crankshaft. A set of gear adjustable lift rods power ejection plate of 
the outer ram for its ejection power. The rods stay engaged against two 
sets of split or clapper blocks which are disengaged at the top of the 
outer ram stroke while the inner ram continues to move upwardly and 
completes ejection of the part. Ejection of the part may be completely 
independent of the die table motion and ejection movement is upward motion 
at all times. 
In operation, the upper punch is started downwardly and enters the die 
cavity approximately 1/8 inch causing the lower ends of the push rods 
tocontact the upper ends of the core plate push rods. As the ram proceeds 
downwardly, it pushes the die table downwardly and pressure from the 
powder fill engages the outer punch, forcing it downwardly. Approximately 
5.degree. from the bottom of the crank stroke, the die table bottoms on 
the bed plate and the outer ram adjusting nut bottoms on the pressure 
plate when the crank reaches full downward position and overtravels. At 
this point everything in the assembly is down. Then the upper punch starts 
back up. At approximately 12.degree. from the bottom or 192.degree. on the 
cam, the ejection arms are engaged by the ejection downshaft from the 
crankshaft cam and the arms move up and engage the ejection nut starting 
the ejection plate upward. Since the ejection plates are tied together by 
lift rods through split blocks on the outer ram ejection plate, this 
permits the plates to move at the same time upwardly until split or 
divider pins engage the bottom of the press bed where ejection of the 
upper level of the part takes place. Upon further movement of the cam, the 
cone heads of the lift rods separate the split blocks and allow the cone 
heads of the lift rods to rise past the split blocks and allow the inner 
ram to finish the ejection stroke.

DETAILED DESCRIPTION OF PRESENTLY PREFERRED EMBODIMENTS OF THE INVENTION 
Referring to FIGS. 1-6 of the drawings, a powdered metal press, shown 
generally at 10, includes four upstanding frame members or legs 12 which 
may be extended below the level of floor 14 to provide stability for the 
press and to facilitate visual observation of the die table 16 of the 
press. The legs 12 provide an outer frame support for a one piece case 
iron frame 18 of the press which is mounted at the upper ends of the frame 
members. A guard 20 is provided to protect an operator from injury from 
the internal press ejection system. 
The press is characterized by two upper punches and two lower punches. As 
shown in FIGS. 1, 3A and 3B, the upper punches 22 and 24 operate in a 
single pneumatic molding action operated by a cam timed with the stroke of 
a crank, allowing the inner top punch to maintain pressure on the part 
with greater travel by the inner punch. The punches are mounted on a top 
ram slide 26 reciprocally driven vertically in gibs 28 by a pitman 30 
mounted on a crankshaft 32 connected to a bull gear 34 which is driven 
from an external source, such as motor 36. 
The press is driven by motor 36 through belts 38 connected to the flywheel 
of a clutch and brake assembly 40. Torque is transmitted to the bull gear 
34 through a pinion 42 mounted on the end of backshaft 44 journaled in a 
pillow block 46 attached to the back of the press frame 18 (See FIG. 3B). 
Rotation of the bull gear 34 via the backshaft 44 also causes rotation, 
via rotation of the crankshaft 32, of a downshaft 48 via gears 50 and 52 
and rotation of three cams 54, 56 and 58 on the downshaft. Cam 54 is 
connected to a cylinder 60 which controls the track of a filler box 62 to 
shaker cam 58, while cam 56 is an air valve control. Linkage 64 from 
cylinder 66 in engagement with shaker cam 60 includes adjustment openings 
68. As will be appreciated from FIG. 3A, the particulate composition is 
supplied to the press from a hopper 70 through flexible tubing 72 
connected into the top of the filler box 62 which is adapted to be moved 
laterally across the upper surface of the die table 16 of the press. 
Referring to FIG. 3A, an ejection cam 74 is also provided on the crankshaft 
32 and cooperates with ejection cam follower 76 which is mounted in a 
housing 78. Ejection arms 80 are pivotally supported on ejection bearing 
brackets 82 and connected by a downwardly extending ejection arm push rod 
84 to the follower 76. The lower ends of the arms 80 are adapted to 
cooperate with the lower press assembly to permit ejection of a finished 
two level powdered metal part 86 such as that shown in FIGS. 22 and 23, as 
will be described hereinafter. 
The lower assembly of the press is suspended from a bed plate 88 by four 
tubular support posts 90, one positioned at each corner of the assembly. 
The upper ends of the support posts are threadably engaged in the bed 
plate and held by nuts 92 (See FIG. 6). The lower ends of the posts 90 
extend through laterally extending pressure plate 94 and are held by nuts 
96 at the bottom of the assembly. 
The die table is supported by four die table support posts 98 which extend 
through the support posts 90. The upper ends of the posts 98 are 
threadably engaged into the die table and held by nuts 100 and the lower 
ends of the posts 98 are held by nuts 102 below core rod plate 104. 
The die table 16 includes a cavity 106 for holding the powdered metal fill 
to be pressed. The die table is floatingly mounted by a pair of die table 
push rods 108 which extend (as shown in FIG. 7) from the top ram slide 26 
to below ejection plate 110 of the lower assembly. The die table push rods 
108 extend within tubular hollow lift rods 112 located between upper 
ejection plate 114 and lower ejection plate 110. The ends of the die table 
push rods 108 extend below ejection plate 110 and are aligned with, but 
normally separated, from core rod plate push rods 116 which are threaded 
into a collar 118 which is held in core rod plate 104 by hub nut 119 (FIG. 
7). 
The lower assembly of the press provides improved means for compacting and 
ejecting the finished workpiece. 
Two lower punches 120, 122 (See FIG. 8) are operable from two independent 
lower rams. The larger punch 120 of the two punches is mounted on an outer 
ram 124 and the smaller or inner punch 122 is mounted on the smaller or 
inner ram 126. Each ram is provided with independent fill adjustment and 
pressure plates. 
As shown in FIG. 3A, outer ram 124 extends above ejection plate 114 and is 
connected thereto by a key plate 128. The position of the outer ram 124 
with respect to the ejection plate 114 is determined by an ejection nut 
adjustment assembly comprising an ejection nut 130 and threaded fasteners 
134 (See FIGS. 7 and 15A). 
The inner ram 126 extends vertically within the outer ram 124 which is 
adjustable by an outer ram float adjustment and lock assembly 136 (See 
FIG. 19). A fill adjustment 138 is also provided. As shown in FIG. 19, an 
outer ram float pot 140 is positioned between the fill nut adjustment 138 
and a pressure plate 142. The amount of float is determined by an 
adjustment nut 141 threaded to pot 140. Outer ram float air cylinders 144 
are provided on opposite sides of the pressure plate 142 and are connected 
via cylinder rods 146 to outer ram float plate 148. The pressure plates 94 
and 142 provide the finished compacting position; they are stationary with 
respect to the press frame. 
The inner ram 126 extends through the outer ram float plate 148 and gear 
means comprising a Browning gear 150, the outer driven gears 152, mounted 
on a hub 103, which engage the ejection lift rods 112 (See FIG. 16), are 
provided adjacent ejection plate 110. 
The details of the press are best understood with reference to the four 
operating conditions of the press structure during the pressing of a 
two-level part 86, such as that shown in FIGS. 22 and 23. The part, in the 
form of a bushing illustrated comprises a body 154 having a top surface 
156, a lower surface 158 on one end and a slot 160 therein. The opposite 
end of the part comprises an extended post 162. The four major positions 
or conditions of the press required to make such a part are shown in FIGS. 
8-11. They are FIG. 8: "Fill;" FIG. 9: "Compaction," FIG. 10: "Ejection 
outer punch;" and FIG. 11: "Ejection inner punch." 
At the outset, the die table 16 is in the full "up" position. Air is 
provided to cylinders 188 which maintain the die table position. Upper 
fill nut 138 and a lower fill nut 139 are adjusted to determine finished 
part length and fill. 
In the "Fill" position shown in FIG. 8, the upper punches 22, 24 are 
separated from the die table 16 by a sufficient distance to permit 
powdered metal 164 to be disposed in the die table cavity 106 from a 
convenient hopper 70 as is conventional in the art. The die table 16 is 
shown spaced above the press bed plate 88. The inner punch 122 and the 
outer punch 120 are both down as far as possible. When filling of the die 
table cavity 106 is complete, the compaction process is begun. 
The inner upper punch 22 is moved downwardly and enters the die cavity 106 
approximately 1/8 inch causing the lower ends of the push rods 108 to 
contact the upper ends of the core plate push rods 116. As the top ram 
slide 26 proceeds downwardly, it pushes the die table 16 downwardly and 
pressure from the powder fill 164 in the cavity 106 engages the upper 
outer punch 24 forcing the punch upwardly. Approximately 5.degree. from 
the bottom of the crank stroke, the die table 16 bottoms on the bed plate 
88 and the outer ram adjusting nut 138 bottoms on pressure plate 142 when 
the crank reaches full downward position, and overtravels in the 
"Compaction" condition causing overtravel spring plate 186 to collapse 
springs 166 and absorb the overtravel pressure. (See FIG. 9). At this 
point the entire lower press assembly is down, the actual full tonnage of 
the press is realized, and air is driven from the air cylinders 188 into a 
reservoir (not shown). Upon final compaction of the part 86, both of the 
lower rams 124, 126 rest on stationary plates which provide a solid base 
necessary for consistency of the part. 
The dual lower rams are controlled by the single cam on the crankshaft 32 
for ejection of the part. Ejection is performed by an upward movement of 
the lower punches 120, 122. While ejection takes place, the die table 16 
is driven upwardly only by pressurized air fed into air cylinders 188. In 
all instances, no die table movement is needed at any time for ejection. 
During ejection, the lower punches 120, 122 begin their upward travel. At 
approximately 12.degree. from the bottom or 192.degree. on the cam, the 
ejection arms 80 are powered by the ejection arm push rod 84 from the 
crankshaft cam 76 and the arms 80 move up and engage the ejection nut 168 
starting the ejection plate 110 upward. Since the ejection plates 110 and 
114 are tied together by lift rods 112 to split or clapper blocks 170 on 
the ejection plate 114 (See FIG. 12), this permits the plate 114 to move 
at the same time upwardly until divider pins 172 engage the bottom of the 
press frame 18 where ejection by the outer punch 120 takes place (FIG. 
10). The split blocks 170 are separated by the downward action of cone 
heads of the divider pins in the grooves 174 between block sections 176, 
178 acting against springs 180 on rods 181 (FIG. 15C). This permits cone 
head 182 of the lift rods 112 to rise past the split blocks 170 (as shown 
in FIG. 15B) and allows the inner ram 126 and inner punch 122 to finish 
the ejection stroke (See FIG. 11). 
The gear train, preferably Browning gears 150 are mounted on top of 
ejection plate 110 for adjustment of the two lift rods 112 which lift 
ejection plate 114 during ejection of the part. Ejection plates 110 and 
114 must start their lift of the part at the same time, but ejection plate 
114 will reach its maximum travel before plate 110. At the time when 
ejection plate 114 reaches its maximum travel, the plate will be held in 
place by air cylinders 144, using air over oil. These so-called "hold-up" 
cylinders are controlled by the cam 56 mounted and timed on the downshaft 
48. The cylinders 144 will hold ejection plate 114 until the part has been 
completely ejected by the plate 110. At this time, the air will release in 
the hold-up cylinder for ejection plate 114 and both plates 110 and 114 
will drop back in place for powder fill. 
An important factor in the speed of the press is that fill takes place 
while the ejection plates are moving into position. Hence, there is no 
lost motion-time. In addition, consistency of the part is achieved since 
the inner and outer punches operate at the same position of adjustment on 
each stroke. 
The core rod mounting is independent of the two lower rams. It can be 
mounted to move with the die plate float or it can be stationary as the 
die plate moves around it. The die plate float is adjustable through gear 
means, such as gear 184 (FIG. 13), which adjusts push rods 116 to provide 
the desired plate float and overtravel. Browning gear 184 meshes with 
outer gears 185 mounted on collar 118. The outer ram float can be tied 
into the movement of the die table 16 through the core rod plate 104 or 
movement can be independent of movement of the die table. In this way, 
density of each level of a two-level part, such as part 86 can be 
controlled. For example, the density through line A in FIG. 22 can be set 
to mold at 6.0 and through line B, the density can be set to mold at 7.0 
at the same time, or the part can be molded at an even density, such as 
6.0, throughout with the density split at line C. 
With these possible movements during molding and the upward ejection 
capability of the lower rams to positively eject the part completely 
independent of die table motion, an extremely versatile powder compaction 
press is provided. 
In an alternative mode the lift rods 112 can be disengaged and only the 
inner ram and punch used if it is desired to make a single level part. In 
this mode, only the lower ejection plate 110 is required for ejection. 
The invention is applicable to either mechanical or hydraulically actuated 
presses of any convenient tonnage. The press can be assembled by skilled 
laborers and operated by semi-skilled operators. 
Having described presently preferred embodiments of the invention, it is to 
be understood that it may be otherwise embodied within the scope of the 
appended claims.