US2043085A - Tablet machine - Google Patents

Description

June 2, 1936.

c. J. wEsTlN Er Al.

TABLET MACHINE Filed Mron '7, 1954 4 sheets-sheet 1 //I/ l/fW 7 0615 d/s 6%@ rs @ec/ June 2, 193(5- c. J. wEsTlN ET A. 2,043,035

TABLET MACHINE Filed March '7, 1934 4 Sheets-Sheet 2 TABLET MACHINE Filed March 7, 1934 4 Sheets-Sham*l C5 .vtwm

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June 2, 1936- I Ac. .1. wEs'rlN ET AL 2,043,085

TABLET MACHINE Filed March 7, 1934 Y 4 Sheets-Sheet 4 V uw.. ma A ,4f afm/EK Patented June z, 1936 l l 2,043,085

UNITED STATES PATENT l,OFFICE AI'ABLET MACHINE Charles J. Westin and Charles J. Beck, Philadelphia, Pa., assignors'to F. J. Stokes Machine Company, Philadelphia, Pa., a corporation of Pennsylvania Application March 7, 1934, Serial No. 714,409

3 Claims. (Cl. 107-1'1) The present invention relates to rotary, tabletwith the mold 22 through cam tracks; 23 for the compressing machines, and pertains particularupper, 54 for the lower; or through the upper 1y to new and useful improvements in the princompressing roll 25 and lower roll 26. ciples of construction which result in economy The diagram Fig. 4 shows step-by-step in se- 5 of manufacture, greater convenience and efliquence the functions of each set of punches for ciency of operation, and which materially ina complete revolution of 360 of the head I5. crease the production rate of the machine. The degrees marked along the top. are arbitrarily More specifically, this invention is particulary chosen and merely serve the purpose of showing 1y directed to means' for yieldingly supporting the synchronized action of the parts. At the 0 the lower roll in operative position; means for line the lower punch 2| starts down opening the 10 adjusting the tension with which said roll is supmold cell and the powder flows in, completing the ported; and means for indicating the adjustment filling at about 95 where the punch again rises, as it is made. lifting some of the powder out of the mold, the Another feature Aof our invention is means for excess being scraped off at 140. From this point ejecting the tablet by simultaneously lifting both the lower punch may travel straight or be low- 15 the punches and the tablet between them, and ered as the case may be, until it strikes the roller then lifting the top punch away from the lower 26 at the same time, or approximately so, that punch, and away from the tablet thereon. the upper punch strikes the roller 25 and the Other objects relating to details and economies powder is compressed into a tablet at 270. At 20 of construction and operation definitely appear the 330 line the tablet has been lifted out of the 20 from the description to follow. mold and rides off the mold table 30 onto the dis- In the drawings: charge chute 3l (Fig. l) at about 350. Fig. l is a perspective view, in elevation, of our Tablet-compressing machines are built in a device; number of sizes and are primarily classified ac- Fig. 2 is a cross-section through a tablet made cordingto the maximum pressure they can exert 25 on the machines of the prior art; on the largest size tablet within the range of the Fig. 3 is a side elevation,'wth parts in crossmachine, but the pressure must be adjustable section, of some details of the machine; so that it can be reduced when smaller size Fig. 4 is a diagram and development of parts tablets are to be made. For example, a threeof the machine and of their operation; ton machine may have a range from 1/8 inch 30 Fig. 5 is a top plan view of the lower cam in diameter tablet up to inch diameter or tablets the adjacent parts; and of areas from .012 square rinch up to .306 square Fig. S is a side elevation of the lower cam. inch, and it is evident that the same pressure In that embodiment of our invention chosen should not be used for the small as for the large. for illustration in the drawings, and particularly In our device, the upper roll 25 is usually rotat- 35 Fig. l, this type of machine is shown as consistable on a xed shaft 80. The lower roll 26 roing of a frame II provided with a base I2, and a tates on shaft 59, mounted in lever 5l which is table I3 having a central spindle thereon, on supported on one end by fulcrum 58 fastened which a rotating head I5 is mounted. The head to table I3, and on the other end by pin 60 con- 4 I5 is mounted for rotation in the direction of the necting it through the adjustable linkage 6I and 40 arrow A, as, for example, by a worm-gear (not pin 64 to the safety release lever 6l. This safety shown) attached to it and co-operating with a release lever 6l has its fulcrum at 66 supported worm (not shown) on shaft I8, Whichrmay conby clevis 65 which is attached to the base II. At veniently be driven from a prime mover through the far end 16 the lever 61 is attached to spring pulleys, or by any other convenient means. The 16 which is fastened to the pad 'I9 of base II by 45 head I5 is of such construction that a number eyebolt 18. Spring 16 is enclosed in a casing or of rings or annular disks are superimposed with spring-chamber 'I1 which serves a three-fold pursmaller rings or necks in between forming a pose: completely encloses the spring 16; supports r structure of several stories and of diameters to end l0 of lever 6l at a predetermined level re- "0 suit the co-acting mechanism. A plurality of gardless of the tension exerted on l0 by spring 16; 50 apertures are spaced around the head and cut provides visible means for controlling the caliclear through the several stories to form bearbrating as well as the adjustment of the spring ings and seats for the plurality of upper punches tension. Heretofore, with the old compound lev- 20, lower punches 2I and molds 22 (best seen in erage and weight mechanism used as a yieldable Fig. 3). The punches are caused to co-operate support for the lower roller 26, it was very diff- 55 cult to get the correct pressure when changing from one size tablet to another and usually meant a. considerable amount of experimenting but with our invention, using the indicator 75 in combination with the graduated scale 14, the adjustments can quickly and easily be made. It is understood that we provide graduation on scale 'M to suit the tension produced at various points when the spring 16 is stretched in making the adjustments. The indicator arrow 15 is mounted on a block 'i3 attached to eyebolt 68, which extends through lever-end 10 and is threaded to co-operate with handwheel 69 for the purpose of increasing or decreasing the pressure as the case may be.

It is a well known fact that springs gradually stretch and for that reason we have provided for recalibrations by mounting plate 14 adjustably on its support. By relieving spring 16 of all tension and setting the 0 graduation of scale 14 opposite the indicator arrow 12, the pressureindicating device is re-calibrated.

We have also provided a safety device to prevent stressing the machine beyond its rated pressure. This consists in a series of spacers 1I made in varying thicknesses and placed between indicator blocks 13 and lever-end 10 to stop the adjustment of eye-bolt 68 when the maximum pressure is reached. After re-calibrating the indicator at the 0 graduation as described above, a check can be made for the maximum pressure by adjusting the indicator arrow 15 up as far as it will go and noting the difference between the arrow and the maximum graduation; removing sufficient spacers will restore the pressure range.

In theA manufacture of compressed tablets from powdered or granular material, there often is, as shown in Fig. 2, a tendency for the upper portion 8 of the tablet to separate from the main portion l. This is a serious dilculty known as capping, and is caused either by unrelieved internal strains or lby entrapped and/or other causes. In many instances, it has been necessary to operate the old type of machines at half the production speed on account of this difficulty, but we have found that, through the use of our improved construction, the capping is eliminated, and the machines may be operated at their full-rated capacity.

As mentioned above, the capping is eliminated through the use of our invention, herein to be referred to as the double-function of the lower punch. Heretofore, these machines were constructed so that the upper punch 20 would be lifted out of mold 22 by cam 53 as soon as the punch-head would clear the roll 25, Figs. 3 and 4. Considerable power is required to break punch 20 loose and lift it out of the mold 22 after compressing a tablet, and it was, therefore, necessary to make use of all the available space to provide a gentle slope on the punchlifting cam 53. 'Ihe lower punch 2i, however,

would ride on, until it reached incline 55 of cam 54 at a farther distant point than the upper punch, before it would be forced by incline 55 to lift the tablet out of mold 22. By this method, the tablet was unsupported on top for a considerable distance before the ejection as well as during the ejection. However, we have found that allowing the upper punch 20 to remain tight and undisturbed on the tablet for a longer time interval is very beneficial in strengthening the tablet, because' it gives any entrapped and cornpressed air a chance to escape, thus eliminating the tendency of "capping. We have also found that these conditions are further improved by making the lower punch 2| lift the upper punch 20 out of the mold 22 by means of the tablet. For this purpose, it is necessary to provide more space for cam 54 so that incline 55 could be made a more acute angle with the horizontal line, or, in other words, slope more gently from the surface of table i3, and thus gently ease the tablet and upper punch out of the mold, without decreasing the range of adjustment for the lower roller 26. One oi' the means resorted to, in providing the needed room, is to make the point of incline 55 at the top of table I3 the same thickness as the distance roll 26 extends above the table, when set for the thickest tablet, instead of a sharp point as heretofore. A bridge 56 also has to be provided to carry the punch from the roll to the cam when using this low position of the roll. As a result, an increase of percent in the production has been obtained in many cases.

We do not intend to be limited save as the scope of the prior art and of the attached claims may require.

We claim:-

1. In a tablet machine, the combination of, a pair of rolls, a base, a lever pivotally mounted on said base and pivotally supporting one of said rolls thereon, a second lever pivoted on said base adjacent said first lever, a link connecting said levers together, a hand-wheel arranged to adjust the length of said link, a spring connected to said base, a spring chamber completely encircling said spring and underlying one end of said second lever so as to provide a stop for said second lever in one direction of movement thereof, an eye-bolt connected to said spring, and a hand-Wheel having screw threaded engagement with said eye-bolt and bearing on said second lever so as to provide means for adjusting the tension with which said spring stresses said second lever.

2. In a tablet machine having a pair of rolls and a pair of vertically aligned punches and means for conveying said punches between said rolls and thereby moving them toward each other to compress a tablet between them, the combination of, a linkage pivotally supporting one of said rolls, a spring connected to said linkage to yieldingly retain said roll in operative position, means for contacting with the lower of said punches after they have passed through said rolls and for lifting said punches and the tablet between them simultaneously by pressure applied to the lower of said punches and with the upper of said punches solely supported on the tablet, and second means to the rear of said first-mentioned means in the direction of movement of punches and co-operating with the upper of said punches for then lifting the upper of said punches away from the lower of said punches and the tablet thereon.

3. In a tablet machine, the combination of, a pair of rolls, a pair of vertically aligned punches, a mold for receiving the operative ends of said punches therein, a table for conveying said punches and said mold between said-rolls, a cam co-operating with the lower of said punches and having a face adjacent the lower of said rolls and sloping relatively gently in relation to the surface of said table to thereby simultaneously lift both said punches and a tablet between them by pressure applied to the lower of said punches 75 the upper of said punches away from the lower of said punches and the tablet thereon after said punches and said tablet have been partially and with the upper o! said punches solely supported on the tablet, and a second cam co-operating with the upper of said punches and having a face to the rear o! said face of said tlrstmentioned cam in the direction of movement of said punches and sloping relatively sharply in relation to the face of said tablet to thereby lift lifted.

CHARLES J. WES'IIN. CHARLES J. BECK.

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