Title:
TABLET CLASSIFICATION MACHINE
United States Patent 3709329


Abstract:
A tablet classification machine has a drum having an inlet end and an outlet end, mounted for rotation and having circular openings having a predetermined diameter to pass tablets having a diameter less than a predetermined diameter and pieces of broken tablets. A tablet supply chute supplies tablets to the inlet end of the drum. A helical blade secured to the interior of the drum advances tablets from the inlet end to the outlet end of the drum. A first classification slide has its upper end below the outlet end of the drum to receive tablets discharged at the outlet end of the drum. The slide has parallel bars spaced apart a predetermined distance to provide for the passage therethrough of tablets having not more than a predetermined maximum thickness. A second classification slide below the first classification slide has parallel bars spaced apart a predetermined distance which is less than the distance between the bars of the first slide in order to retain tablets having more than a predetermined minimum thickness. A chute below the first slide and above the second slide collects tablets passing through the first slide and discharges them adjacent the upper end of the second slide.



Inventors:
MLODZINSKI J
Application Number:
05/185141
Publication Date:
01/09/1973
Filing Date:
09/30/1971
Assignee:
SMITH KLINE & FRENCH LAB,US
Primary Class:
Other Classes:
209/677, 209/683, 209/913
International Classes:
B07C5/06; (IPC1-7): B07C5/04
Field of Search:
209/95,75,86,97,99,107
View Patent Images:
US Patent References:
3612273SEPARATOR1971-10-12Pritchett
3347368Screening device1967-10-17Mogensen



Primary Examiner:
Schacher, Richard A.
Assistant Examiner:
Church, Gene A.
Claims:
I claim

1. A tablet classification machine comprising:

2. A machine in accordance with claim 1 in which the parallel bars of both slides are round.

3. A machine in accordance with claim 2 in which a helical blade is secured to the interior of the drum to advance tablets from the inlet end to the outlet end of the drum.

4. A machine in accordance with claim 1 in which a helical blade is secured to the interior of the drum to advance tablets from the inlet end to the outlet end of the drum.

5. A machine in accordance with claim 4 having spaced parallel bars adjacent and below the outlet end of the drum to spread out the tablets discharged from the drum.

6. A machine in accordance with claim 1 in which the drum is mounted for rotation on idler rollers, and the means to rotate the drum includes a ring gear secured to the drum and a driven gear engaging the bottom of the ring gear permitting the drum to be removed freely.

7. A machine in accordance with claim 1 having spaced parallel bars adjacent and below the outlet end of the drum to spread out the tablets discharged from the drum.

Description:
BACKGROUND OF THE INVENTION

In the process of manufacturing pharmaceutical tablets variations in the diameter and thickness of the tablets result. Generally, it is desired to package for sale only the tablets which fall within ranges of diameters and thicknesses which are exceeded by some of the tablets. Thus, it is necessary to eliminate the tablets which exceed these ranges. The machine of this invention provides a rapid means for classifying tablets to eliminate the tablets outside of the desired ranges and pieces of broken tablets at very small cost.

SUMMARY OF THE INVENTION

A tablet classification machine comprises a drum having an inlet end and an outlet end, mounted for rotation, and having circular openings having a predetermined diameter to pass therethrough tablets having a diameter less than a predetermined minimum diameter and pieces of broken tablets. The drum is rotated on its axis. A first classification slide has its upper end below the outlet end of the drum to receive tablets having at least the predetermined minimum diameter. The first slide has parallel bars spaced apart a predetermined distance to permit passage therethrough of tablets having less than a predetermined thickness to a second classification slide positioned below the first classification slide. The second classification slide has parallel bars spaced apart a predetermined distance which is less than the distance between the bars of the first slide to retain tablets having more than a predetermined thickness. In this manner only tablets within a desired range of thickness are selected. A chute mounted below the first slide and above the second slide collects tablets passing through the first slide and discharges them adjacent the upper end of the second slide.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front elevation of a tablet classification machine in accordance with the invention;

FIG. 2 is a vertical section, partially broken away, of the machine of FIG. 1;

FIG. 3 is a top plan view of the machine of FIG. 1;

FIG. 4 is a top plan view of the upper classification slide of the machine of FIG. 1;

FIG. 5 is a section taken on the plane indicated by the line 5--5 in FIG. 4;

FIG. 6 is a section, partially broken away, taken on the plane indicated by the line 6--6 in FIG. 2, and

FIG. 7 is a section, partially broken away, taken on the plane indicated by the line 7--7 in FIG. 2.

PREFERRED EMBODIMENT

Referring first to FIG. 1, a tablet classification machine 2 in accordance with the invention has a supporting framework 4. A drum 6 has its major portion perforated with openings 8 which are circular and of the same diameter which is selected so as to retain within the drum tablets having a diameter greater than a predetermined minimum diameter. Openings 8 are of primary importance in permitting pieces of broken tablets to pass therethrough out of the drum. Drum 6 has ring portions 10 and 12 which rest on idler rollers 14 and 16 and 18 and 20 respectively (FIG. 3), these idler rollers being journaled on framework 4. A ring gear 26 secured to drum 6 is driven by a gear 28 which in turn is driven by a motor and reduction gear unit indicated at 30.

Tablets are supplied to drum 6 from a hopper 34 which is mounted on and communicates with a slide 36 which discharges into the interior of drum 6 as best seen in FIG. 2. Slide 36 is mounted on a vibrator 38 to cause tablets to advance along the slide into drum 6 in a conventional manner.

A chute 40 is positioned below drum 6 to catch tablets and pieces of broken tablets falling through openings 8. Chute 40 discharges into a second chute 42 which in turn discharges into a waste container 44 mounted on a platform 45.

Deflector plates 46 and 48 attached to frame 4 on either side of drum 6 act to guide particles passing through openings 8 in drum 6 into chute 40.

Drum 6 has secured to its interior surface a helical blade 52 which, as the drum rotates clockwise as viewed from the right hand end of FIG. 2, advances tablets from the inlet end of the drum 6 to the outlet end where the discharged tablets fall onto spaced bars 54 secured to U-shaped member 56. The bars 54 allow free passage of the tablets and serve to spread the tablets over a wide area.

Tablets passing through spaced bars 54 drop onto slide 58 which has spaced parallel round bars 62 secured as by welding to support members 64 and 66 which in turn are mounted on brackets 68 and 70 secured to a frame 71 slideably mounted on brackets 71A and 71B secured respectively to walls 72 and 74. Slide 58 extends from a point adjacent wall 72 to a point adjacent wall 74. A panel member 76 welded to the rearmost bar 62 fills the gap between the rearmost bar 62 and rear wall 78. Similarly, a panel member 76 (FIG. 4) welded to the frontmost bar 62 fills the gap between the frontmost bar 62 and access door 82 which, as shown in FIG. 3, is hinged to wall 72 at 84.

Bars 62 are spaced apart to provide for the passage therethrough of tablets 86 having not more than a predetermined maximum desired thickness (FIG. 6). The retained tablets slide downwardly and gather adjacent gate 88. When a substantial pile of retained tablets has accumulated, gate 88 is raised by means of handle portion 90 (FIG. 6) and the tablets pass to waste container 91 contained in housing 92. Container 90 has a front panel 94 which completely closes off the front opening of housing 92 and is provided with a knob 96 to facilitate the removal of container 91 (FIG. 1).

A slide plate 100 catches tablets passing through slide 58 and discharges them adjacent the upper end of a slide 102 which has spaced parallel round bars 104 secured as by welding to support members 106 and 108 which in turn are supported on brackets 110 and 112 respectively, slide 102 extending from adjacent wall 74 to a point adjacent wall 72 which is provided with a discharge opening 114 for the passage of tablets retained on slide 102. Brackets 110 and 112 are secured to frame 115 which is slideably mounted on brackets 115A and 115B secured respectively to walls 72 and 74. Bars 104 are spaced closer together than are bars 62, the distance between bars 104 being selected to retain tablets having more than predetermined minimum thickness. In a manner similar to slide 58, slide 102 has panel members 76 (FIG. 7) at the front and back to fill in the gaps adjacent rear wall 78 and door 82.

The tablets passing through slide 102 are caught in a waste container 116 which can be removed for emptying when door 82 is opened. The tablets retained on slide 102 passing through opening 114 drop into chute 120 which discharges the tablets onto a belt conveyor 122. A deflector cover 124 is mounted above chute 120 adjacent to opening 114.

By way of a typical example openings 8 may have a diameter of 0.375 inch, bars 62 may be spaced apart 0.240 inch, and bars 104 may be spaced apart 0.187 inch.

The operation of the above described machine is obvious from the foregoing description. The embodiment described is illustrative and is not intended to be limiting.