US2537426A

US2537426A - Fill adjusting mechanism for molding presses

Info

Publication number: US2537426A
Application number: US64385A
Authority: US
Inventors: Royal B Saalfrank
Original assignee: Stokes Machine Co
Current assignee: FJ Stokes Machine Co
Priority date: 1948-12-09
Filing date: 1948-12-09
Publication date: 1951-01-09
Anticipated expiration: 1968-01-09

Description

Jan. 9, 1951 R. B. SAALFRANK FILL ADJUSTING MECHANISM FOR MOLDING PRESSES Filed Dec. 9, 1948 2 Sheets-Sheet 1 INVENTOR. R YAL B- SA LFRANK 14 a aw T ORNEY Jan- 1951 I R. B. SAALFRANK 2,537,426

FILL ADJUSTING MECHANISM FOR MOLDING PRESSES Filed Dec. 9, 1948 2 Sheets-Sheet 2 J TI? IN V EN TOR.

R ws; B. SP P LFRANK BY ATTO RNEY Patented Jan. 9, 1951 FILL ADJUSTING MECHANISM FOR MOLDING PRESSES Royal B. Saalfrank, Philadelphia, Pa., assignor to F. 3. Stokes Machine Company, a corporation of Pennsylvania This invention relates to molding presses, and

it is concerned especially with an arrangement for adjusting thefill of the press to vary the amount of material pressed into each molded article, and also varying the stroke of the ejection of molded articles of different thicknesses.

An object of the invention is to devise a mechanism by which the ejection stroke of a press is adjusted with adjustment of the fill of the press to insure that the ejection punch or plunger will always come flush with the die surface for different adjustments of fill.

Another object is to devise a mechanism of the type just described which may be adjusted while the press is in operation.

The present invention is an improvement over single punch presses now in common use in which the fill of the press is adjustable by adjusting the vertical height of an anvil on which the lower plunger carrying the lower punch is seated during the filling and compressing stages of the molding cycle. In such machines, the ejection lever provided with a forked end embracing the lower plunger has a constant throw and engages a collar on the lower plunger on its upward stroke to raise the lower punch to a position where its end is flush with the surface of the die table. In molding thin tablets, the anvil is elevated until the end of the lower punch is only a small distance below the top surface of the die, whereas in the case of thick tablets, the anvil is lowered until the end of the punch lies considerably below the top of the die. Since the ejection lever or fork has a constant throw, there will be more or less wind-cutting of the fork, depending upon the thickness of the tablet being molded. For very thick tablets, the fork cuts very little wind, but for thin-tablets there is considerable wind-cutting.

Accordingly, a further object of my invention is to devise an arrangement for adjusting the fill of a molding press which eliminates wind-cutting of the ejection lever for all adjustments of Still another object is to devise a mechanism for simultaneously adjusting the ejection stroke of the press and the vertical position of the anvil which supports the ejection plunger during the compression stage of the molding cycle.

The invention is illustrated in the accompanying drawing in which Figure 1 is a sectional view of the press taken along a vertical plane passing through the center of the press but showing only so much of the punch or plunger to secure proper ejection bears against wear plates "in the slot.

Application December 9, 1948, Serial No. 64,385 10 Claims. (01. 18-16) press as is necessary to explain the invention;

and

Figure 2 is a perspective view of the essential parts of the arrangement for simultaneously adjusting the fill, the ejection stroke, and the vertical'position of the anvil of the press.

Referring to the drawing, l indicates a suitable frame which supports the die table 2 having a vertical die opening or cavity Z'a. A lower punch 3 is mounted with its upper end in the die cavity 2a and extends downwardly through a guiding bearing formed in frame part la. The press includes an upper punch 4 suitably mounted for reciprocation into the upper end of the die cavity 2, and since the arrangement for mountin and operating this punch forms no part -ofthe present invention it is not described herein. The lower end of the punch 3 rests upon the upper end of an anvil 5 at the point 3a, and the anvil is arranged to be adjusted in height by an arrangement to be described later.

The punch 3 normally rests upon the anvil 5 during the compression portion of the molding cycle, and. is then moved upwardly to effect ejection of the molded article from the die cavity. The arrangement for operating the punch 3 during ejection involves a bell-crank 6 pivotally'supported by a pin I on a yoke 8 which is mounted for vertical adjustment as will be explained later.

A horizontal arm 6a of the bell-crank 6 extends into a vertical slot formed in the lower end of the punch 3, and the rounded head of the arm Ba 31) and 30 positioned The vertical arm 6b of the bell-crank carries a pin 9 at its upper end, and a slide I0 is pivotally mounted upon the pin 9 on the far side of the arm as shown in Figure l. The slide It is positioned between, and in sliding contact with, a pair of wear plates Ila and Nb rigidly mounted 'in a recessed portion of a rock shaft !2 having a rocking axis shown at l2a arranged parallel with and vertically above the pivotal axis of th bell-crank 6.

The shaft I2 is given a rocking or oscillating motion of constant amplitude following each compression stage in the molding cycle, and the oscillation of the shaft may be accomplished in any suitable manner. may be provided with an arm or lever it which For example, the shaft has pivotally mounted on the end thereof a roller l4 which engages a suitably shaped cam operated in timed relation with the operation of the upper punch lto oscillate the shaft l2 after the upper punch is withdrawn from the cavity following compression of the molded article.

Figure 1 shows the various parts of the press in their operative positions during the filling of the die cavity, and also during the compression stage of the molding cycle.

When the molded article is to be ejected, the cam follower it: rotates rock shaft i2 clockwise through a given angle and this causes the bellcrank to be rocked counterclockwise, and the arm 6a of the bell-crank raises the lower punch 3 until its upper end is flush with the top of the die table 2. After this, the rock shaft 12 is moved in a counterclockwise direction and returned to the position shown in Figure l, and the press is ready to receive another charge of molding material.

The arrangement for varying the fill of the press comprises an arrangement for raising or lowering the yoke 8 which supports the bellcrank 6, and includes a threaded shank Be on the yoke 8 having threaded engagement with a sleeve 15 mounted for rotation about a vertical axis in a bore 16 formed in the bottom portion of the frame I. The rotary axis of the sleeve 15 intersects the axis la of the pin 1 and the axis 12a of the rock shaft i2, By rotating the sleeve 15 to lower the yoke 8, the normal position of the arm Ba will be lowered, and the stroke of the arm will be increased. Conversely, by rotating sleeve IE to raise the yoke 8, the stroke of the arm will be decreased.

As the stroke of the arm 6a is changed, it is also necessary to change the position of the anvil 5 which supports the lower end of the lower 2 plunger 3 during the filling and compressing stages of the molding cycle, and this is accomplished by mounting the anvil 5 in screw threaded engagement with a rotary sleeve I'l positioned within a vertical bore formed in the lower wall of the frame l.

Sleeves l5 and ii are rotated simultaneously by a gear train comprising gears I50, and I'm secured respectively to the upper ends of the sleeves l5 and ii, and an intermediate idler gear 18 journaled on a stub shaft 19 secured in the lower wall of the frame I. The gear train may be operated by a. suit-able arrangement involving a pinion 29 secured to a vertical shaft 2| which is journaled at its upper and lower ends in suitable bearings formed in frame i and is provided near its upper end with a bevel gear 22 meshing with a second bevel gear 23 carried by a horizontal shaft 24 journaled in the front wall of frame I and carrying a hand wheel 25 mounted on its outer end. By turning hand wheel 25 in one direction or the other, the sleeves l5 and I! may be rotated in one direction or the other to simultaneously raise or lower the yoke 8 and the anvil 5.

The anvil 5 must be held against rotation, and for this purpose an arm 26 is secured within a transverse slot formed in the upper end of anvil '5 and is provided with a forked end embracing the shaft 2!. This arrangement is clearly shown in Figure 2, and it serves to prevent rotation of the anvil 5 while permitting axial movement thereof.

Yoke 8 supporting the ejection lever B may be held against lateral deflection during ejection by means of a pair of bosses 81) having vertical faces which bear against a vertical wall portion ie of the frame 5. This arrangement permits vertical movement of the yoke while restraining it against lateral movement during ejection operation. The threaded sleeve I5 is retained in 4 7 its hearing b means of an angle piece lb clamped to the lower wall of the frame I and engaging the upper face of the gear Mia, and also by a circular plate [9a, mounted on the upper end of stud [9.

In the normal position of the rock shaft 12 as shown in Figure 1 with the axis of lever 13 in the position A, the wear plates Ha and lib forming a guide for the sliding block iii are inclined to the vertical by a given angle as shown.

The rock shaft l2 has a constant angle of rock or oscillation from the position shown in Figure l to a position where the wear plates Ha and Nb are inclined to the vertical, on the opposite side thereof, and preferabl by the same angular amount. The arrangement is such that when the yoke 8 is elevated to a point where the axis ila of the pin 9 coincides with the rotary axis 12a of the shaft [2, the upper end of the punch 3 will be flush with the upper surface of the table 2, and oscillation of the rock shaft will not cause any movement of the punch 3. This is the position of adjustment for zero fill of the press.

As the yoke 8 is moved downwardly to increase the separation of the pin axis So from shaft axis (2a, the angle of oscillation of the bell-crank 5 is increased, and the stroke of the punch 3 is correspondingly increased.

Operation of the arrangement shown in the drawing is believed to be clear from the foregoing description, but may be summarized as follows:

Following the compression step in each molding cycle, rock shaft 12 is oscillated or rocked through a constant angular movement from the normal position shown in Figure 1 with the axis of lever l3 in the position A to the position B where the wear plates [la and Nb are inclined to the vertical in the opposite direction from that shown in Figure 1, and preferably by the same angular amount. These wear plates in combination with the slide ll] constitute an oscillating lever operated by the shaft 52 and having a variable length determined by the vertical adjustment of the yoke 3. As shown in Figure 1, the length of the lever arm is the'distance between the axis to of the pin 9 and the axis 12a ofthe shaft l2. As this lever arm is moved from the inclined position shown in Figure 1 to the oppositely inclined position, the bell-crank 6 will be rotated in a counter-clockwise direction to a position where the upper end of the punch 3 is flush with the upper surface of the die table .2, and the ejected article is in a position to be pushed across the die table by the feeding shoe, not shown. If the fill of the press is increasedby lowering the yoke 8, the length of the oscillating lever Sci-42a will be increased, and this will result in a greater angular oscillation of the bellcrank, and a greater throw of the punch 3.

In order that the lower end of the punch 3 should maintain contact with the upper end of the anvil 5 for different adjustments of the fill, a number of design factors must be related, including the pitch of the threads on anvil 5 and yoke shank 8a, and the ratio of the arm lengths on bell-crank '5 and the angle of inclination of the lever 9a--I2a in the normal position of shaft 12. The drawing shows only one arrangement amon a number of possible arrangements, in which the arm 6a is twice the length of the arm to and the pitch of the threads on anvil 5 is twice the pitch of the threads on yoke shank Ba. With this arrangement, contact is maintained between the lower end of punch 3and the anvil 5 by arrang ing the angle of the lever Sa-lZa so that the axis 911 of the pin 9 is deflected laterally from the vertical by one-half the vertical movement of the yoke 8. In this case, the angle to the vertical will be approximately 26.5 degrees. With this arrangement, the punch 3 will always move toa position where the upper end thereof is flush with the top of the table 2 when the arm I3 is in position B and the arm 9ai2a is inclined to the vertical on the opposite side thereof and by the same angle.

1 The angle of the arm sci-ma in the position A of the lever is may be changed by changing the pitch of the threads on anvil 5. For example, if the arm 9a-i2a is in a vertical position normally, the threads on anvil 5 would have the same pitch as the threads on shank 8a, but the extent of angular oscillation of the arm 53 would be reduced to one-half of the throw formerly employed, that is, it would be reduced to approximately 26 5 degrees instead of approximately 53. Also, it is obvious that in the arrangement shown in the drawing the correct ratio of vertical movement of the anvii 5 with respect to the yoke 8 may be obtained by using threads of equal pitch on these two elements and by'selecting the proper gear ratio between gears I511 and He.

While I have described and shown one specific embodiment of my invention and have given specific ratios of arm lengths, angles and thread pitches, it will be understood that this design data has been given for the purpose of explain. ing the principle of my invention and not by way of limitation.

K I claim:

1. In a molding machine, the combination of a die having a vertical bore, a punch entering the lower end of said bore and H101 d for reciprocation in said bore, an anvil mounted vertical adjustment below said punch and serving to support said punch during the compressing stage of a molding cycle, a bell-crank lever pivoted on a horizontal axis and having a horizontal arm and a vertical arm, a connection between said horizontal arm and said punch for reciprocatin said punch, a rocinshaft mounted on a horizontal axis in the same vertical plane as the axis of said bell-crank lever and having a rocking lever arranged in overlapping relation with the vertical arm of said bell-crank, means pivotally connecting said vertical arm with said rocking lever and having sliding contact with said rocking lever to permit variation in the length thereof, adjustable means for varying the separation between the pivotal axis of said bell-crank and said rock shaft to thereby vary the effective length of said rocking lever, and common means for operating said adjustable means and for simultaneously adjusting the height of said anvil.

2. A machine according to claim 1 wherein said rocking lever has a fixed angular throw and in one end position of the throw the lever is inclined at an angle to the vertical such that the upper end of said punch remains flush with the upper end of said die for all variations in the length of said rocking lever.

3. In a molding machine, the combination of a die having a vertical bore, a punch entering the lower end of said bore and mounted for reciprocation in said bore, an anvil mounted for vertical adjustment below said punch and serving to support said punch during the compressing stage of a molding cycle, a bell-crank lever pivoted on a horizontal axis and having a horizontal arm and zontal arm and said punch for-"reciprocating said punch, a rock-shaft mounted on a horizontal axis in the same vertical plane asthe axis of said bellcrank lever and having a rocking lever arranged in overlapping relation with the vertical arm of said bell-crank, means pivotally connecting said vertical arm with the lever on said rock shaft, said means having sliding contact with one of said connected levers to permit variation in the length of said one lever, adjustable means for varying the separation betweenlthe pivotal axis of said bell-crank and said rock-shaft to thereby vary the effective length of said one leveiyand common means for operating said adjustable means and for simultaneously adjusting the height of said anvil.

4. In a molding machine, the combination of a die having a vertical bore, a punchv entering the lower end of said bore and mounted for reciprocation in said bore, a bell-crank lever pivoted on a horizontal axis and having a horizontal arm and a vertical arm, a connection between said horizontal arm and said punch for reciprocating said punch, a rock-shalt mounted on a horizontal axis in the same vertical plane as the axis of said bed-crank lever and having a rocking lever arranged in overlapping relation with the vertical arm of said bell-crank, means pivotally connecting said vertical arm with the lever on said rock shaft, said means having sliding contact with one of said connected levers to permit variation in the length of said one lever, and ad ustable means for varying the separation between the pivotal axis of said bell-crank and said rock shaft to thereby vary the effective length of said one lever. V

5. In a molding machinathe combination of a die having a vertical bore, a punch positioned in the lower end of said bore and mounted for reciprocation in said bore, a bell-crank lever pivoted on a horizontal axis and having a horizontal arm and a vertical arm, a connection between said horizontal arm and said punch for reciprocating said punch, a rock shaft having a fixed angular throw and being mounted on a horizontal axis in the same vertical plane as the axis of said bell-crank, a rocking lever carried by said rock shaft and arranged in overlapping relation with a vertical arm of said bell-crank, means pivotally connecting said vertical arm with said rocking lever, said means having sliding contact with said rocking lever to permit variation in the effective length thereof, and adjustable means for varying the separation between the pivotal axis of said bell-crank and the axis of said rock shaft to thereby vary the effective length of said rocking lever, said rocking lever being arranged so that in one end position of its throw, it is inclined at an angle to the vertical such that the upper end ofsaid punch remains flush with the upper end of said die for all variations in the distance of separation'between the pivotal axis of the bell-crank and the axis of the rock shaft.

6. A molding machine according to clam 5 wherein the vertical arm of said bell-crank is one-half the length of the horizontal arm, and said rocking lever, in said one end position, is inclined to the vertical by an angle of substantially 26.5 degrees.

7. In a molding press, the combination of a die having a vertical bore, a punch entering the lower end of said bore and mounted for reciprocation in said bore, an anvil arranged below said punch and mounted for vertical adjustment below said punch and serving to support said punch a vertical arm, a. connection between said horiduring the compressing stage of the molding cycle, an ejection lever, means to oscillate said lever, a. connection between said lever and said punch to move said punch in reciprocating movement throughout the oscillation of said even means to adjust the extent of throw of said oscillating lever, and common means for operating said throw adjusting means to increase said throw and for simultaneously lowering said anvil.

8. In a molding press, the combination of a die having a vertical bore, a punch entering the lower end of said bore and mounted for reciprocation in said bore, an anvil mounted for vertical adjustment below said punch and serving to support said punch during the compressing stage of the molding cycle, an ejection lever, a rocking lever having a fixed angular throw, a connection between said rocking lever and said ejection lever to reciprocate said punch throughout the oscillation of said rocking lever, means for shifting said connection along one of said levers to vary the efiective length thereof and thereby vary the throw of said punch, and common means for operating said throw varying means to increase said throw and for simultaneously lowering said anvil.

9. In a molding press, the combination of a die having a vertical bore, a punch entering the lower end of said bore and mounted for reciprocation in said bore, an anvil arranged below said punch and mounted for vertical adjustment and serving to support said punch during the compression stage of the molding cycle, a pivoted lever, means to oscillate said lever, a connection between said lever and said punch for moving said punch throughout the oscillation of said lever to reciprocate said punch between an upper position where the end of the punch is flush with the upper end of said bore and a lower position, means for adjusting the throw of said lever to maintain the same upper position of said punch while lowering the lower position thereof, and means operable simultaneously with said throw adjusting means for moving said anvil vertically to maintain said anvil substantially in contact with said punch in its lower position for difierent adjustments of said throw adjusting means.

10. In a molding press, the combination of a die having a vertical bore, a punch positioned in the lower end of said bore and mounted for reciprocation in said bore, an anvil arranged below said punch and mounted for vertical adjustment, a lever having a fixed pivot between the ends thereof, an adjustable stroke rocker element connected to one end of said lever and serving to oscillate said lever, a connection between the other end of said lever and sa (1 punch for moving said punch throughout the oscillation of said lever to reciprocate said punch between an upper position and a lower position, means for adjusting the stroke of said rocker element to vary the throw of said punch while maintain'ng the end of the punch level with the top of the die in the upper position of said punch, and means operable simultaneously with said stroke adjusting means for moving said anvil vertically to maintain said anvil substantially in contact with said punch in its lower position for different adjustments of throw of said punch.

ROYAL B. SAALFRANK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 686,765 Richards Nov. 19, 1901 876,388 Nieters Jan. 14, 1908 1,295,760 Klay Feb. 25, 1919 2,232,180 Kux Feb. 18, 1941