US3276079A - Feed frame - Google Patents

Description

0d. 4, 1966 R. M. COHN 3, 7

FEED FRAME Filed April 9, 1965 2 Sheets-Sheet l INVENTOR.

FIG 2 BY f? ZZZ A TTOPNEV Oct. 4, 1966 R. M. COHN 3,

FEED FRAME Filed April 9, 1965 2 Sheets-Sheet 2 YINVENTOR. ROBERT/14 C OHN A T TO/Q/VEV United States Patent 3,276,079 FEED FRAME Robert M. Cohn, Colonia, N.J., assignor, by mesne assignments, to E. R. Squibb & Sons, Inc., New York, N.Y., a corporation of Delaware Filed Apr. 9, 1965, Ser. No. 446,880 2 Claims. (CI. 18-20) This invention relates to tableting pulverant materials such as pharmaceutical compositions, ceramics and powdered metals, and more particularly, to an improved feed frame for tablet making machines that form tablets.

A fairly substantial variety of powders cannot readily be tabletted by automatic tablet making machinery because the same do not flow freely under the influence of gravity. Thus, with many forms of powdered materials, resort must be had to either wet granulating processes or dry granulating processes, commonly called slugging, to render the powders sought to be tabletted into a granular state in which they may be tabletted by present-day high speed tablet making machinery. As both wet granulating techniques and dry granulating techniques are dependent upon a plurality of operations, each involving a variety of types of equipment, the same are expensive both in terms of equipment and labor, and materially add to the cost of the tablet.

Further, present feed frames are constructed in such a manner that powdered materials, either wet or dry, are repeatedly passed over a die in the automatic tablet making machine. This is accomplished by having minute portals that are non-aligned in the feed frame which cause the powdered materials to be conveyed over a single die several times. Such feed frames have been known to malfunction due to an excess of powdered material in the feed frame portals which are unable to accommodate this abundance of material.

In addition, prior machines utilized in the tableting of fine powders require the utilization of pressure or agitation equipment.

It has been surprisingly discovered that a feed frame having parallel feed ridges therein whereby particulate matter may flow over a die and attached to a tablet making machine allows fine particles to be tabletted at high speeds, relying on gravity alone. Further, the apparatus improvement of this invention requires that the parallel ridge be from one-eighth of an inch to eight inches long, but more preferably from three to five inches long and from one quarter of an inch to three inches high, but more preferably from one half inch to one and a half inches. The space between the ridges may vary between one-eighth of an inch and one inch. This improvement has been unexpectedly found to be adaptable for both wet and dry granulating techniques. The apparatus improvement of this invention is preferably utilized on particle sizes of from 20 to 300 mesh, more preferably from 50 to 200 mesh for direct compression powders, and from 18 to 250 mesh, more preferably from 30 to 200 mesh for wet granulated powders.

It has been unexpectedly found that the apparatus improvement of this invention permits the rapid and uniform tablet formation of fine fluffy powders having a bulk density of from about 0.3 to 0.7 gram per cubit centimeters for direct compression granulations and from about 0.4 to 0.9 gram per cubic centimeters for wet granulation.

For the purpose of illustrating the invention, there is shown in the drawings, forms which are presently preferred; it being understood, however, that this invention is not limited to the precise arrangements and instrumentalities shown.

FIG. 1 is a plan view of a tablet making machine partially broken away and with the upper punches and other super-structure removed;

FIG. 2 is a development of the press shown in part in FIG. 1; and,

FIG. 3 is an elevated top view of the improved feed frame of the invention.

Referring to the drawings, the rotary tablet press there shown is adapted to make tablets and comprises a die head 1 having vertical die cavities 2 extending therethrough and feed frame 101. This feed frame comprises attachment arms 49, guide plate 37, scrape-off plate 23 and parallel feed ridges 41 and 41b, and scrape-off spring 45. Parallel feed ridges 41a and 41b form feed channel 45 which hedges in die 2. Upper punches 3 are disposed above the die head. Each upper punch is vertically aligned with a die cavity and extends through a passageway 4 in upper punch guide plate 6. The punches are free to move vertically in the guide plate passageways. Lower punches 7 are disposed beneath the die head. Each lower punch is likewise vertically aligned with a die cavity and extends through a passageway 8 in lower "ice punch guide plate 9 in which the lower punches are free to move vertically. The die head 1 and punch guide plates 6 and 9 are permanently secured together and rotate together carrying the punches with them about the pedestal 11. Feed frame 101 is secured to the super-structure (not shown) by attachment arms 49. Any suitable drive means may be used for this service.

An upper cam track 12 and a lower cam track 13 are mounted, respectively, above and below the upper and lower punches, and are fixedly secured to the pedestal 11. The upper cam track causes the upper punch working ends 14 to vertically reciprocate into and out of the die cavities and the lower cam track causes the lower punch working ends 16 to vertically reciprocate up and down in the die cavities.

The upper and lower cam tracks complement each other so that for each revolution of a die cavity and the upper and lower punches associated therewith, a sequence of operations is performed whereby a tablet is formed. Referring to the reference letters of FIG. 1, FIG. 2 and FIG. 3 at tablet material receiving position A, pulverant material M is delivered to the die head 1 from feed hopper 17 which is secured to the pedestal 11. At this position, upper punch 3 is raised and lower punch 7 is extended partway into die cavity 2, and material M is conveyed into feed channel 55 between ridges 51a and 51b and falls uniformly by gravity into the die cavity.

Position B is a weight adjustment position. Here the volume of material, and hence the weight is controlled. At this position, the lower cam track comprises a selectively vertically adjustable cam 18. The adjustable cam 18 is mounted in the bracket 19 which is secured to the pedestal 11. Adjustment is made manually by operation of the lock nuts 21 and 22 to obtain the desired level of the working end of the lower punch in the die cavity. As the lower punch rides over adjustable cam 18, it passes under scrape-oflf plate 23 which rests slidably by scrapeotf spring 42 on the upper surface of the die head and wipes therefrom tablet material outside the die cavity. Thus, as the die cavity leaves position B, it is filled with tablet material above the Working end of the lower punch.

At position C, the tablet material is compressed to form therefrom 'a self-supporting tablet layer T Both the upper and lower cam track at this position comprise a selectively vertically adjustable cam. Adjustable cam 24 in the lower cam track is in the form of a cam surface and adjustable cam 26 is in the form of a pressure roll. Cam 24 and 26 are mounted in adjustable brackets 27 and 28, respectively. These cams are adjusted so that at the end of the compression, the desired degree of compression will be attained.

Position D is a selectably operable ejection position.

Tablet T may be taken off at position E or pass on for further tableting. For the purposes of illustration, T is shown being taken off at position D.

At operable ejection position D, lower cam track 13 comprises a manually operated cam 42 which when raised, ejects tablet layer T from the die cavity. Take off plate 43 intercepts the path of ejected tablet T and directs tablet layer T off the die head into chute 44.

While there have been described various embodiments of the invention, the compositions and methods described are not intended to be understood as limiting the scope of the invention, as it is realized that changes therein are possible and it is further intended that each element recited in any of the following claims is to be understood as referring all equivalent elements for accomplishing substantially the same results in substantially the same or equivalent manner, it covering the invention broadly in whatever form its principle may be utilized.

What is claimed is:

1. In a tablet-making machine for forming tablets comprising rotatable die table having a plurality of circumferentially spaced dies and a feed means for providing a How of powder thereto, the improvement which comprises an attachment for directing powder to said dies having a cavity therein enlarged at either end and a substantially parallel narrow portion in its middle, said attachment being placed on said machine so that the middle portion of said cavity coincides with said dies.

2. An improvement in accordance with claim 1 wherein the narrow portion of said cavity has a width at least equal to the Width of said circumferentially spaced dies.

References Cited by the Examiner UNITED STATES PATENTS WILLIAM J. STEPHENSON, Primary Examiner.

Claims (1)

1. IN A TABLET-MAKING MACHINE FOR FORMING TABLETS COMPRISING ROTATABLE DIE TABLE HAVING A PLURALITY OF CIRCUMFERENTIALLY SPACED DIES AND A FEED MEANS FOR PROVIDING A FLOW OF POWDER THERETO, THE IMPROVEMENT WHICH COMPRISES AN ATTACHMENT FOR DIRECTING POWDER TO SAID DIES HAVING A CAVITY THEREIN ENLARGED AT EITHER END AND A SUBSTANTIALLY PARALLEL NARROW PORTION IN ITS MIDDLE, SAID ATTACHMENT

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