US3549056A - Powder feed hopper for capsule-forming machine - Google Patents

Description

United States Patent Inventor Maharaj Krishen Mehta Lakeside, Cardiff, Wales Mar. 10, 1969 Dec. 22, 1970 P. Leiner & Sons (Encapsulations) Limited Treforest, Glamorganshire, Wales Appl. No. Filed Patented Assignee POWDER FEED HOPPER FOR CAPSULE- FORMING MACHINE 5 Claims, 3 Drawing Figs.

U.S. Cl 222/226,

Int. Cl. F0lf 11 00, F014 13/00 Field of Search 222/226,

25 l 252. 505(T), 510: 259/2(T), 28(T) [56] References Cited UNITED STATES PATENTS 2,798,645 7/1957 Keen et al 222/226 2,801,774 8/1957 l-larkess et al. 222/226 Primary Examiner-George T. Hall Attorney-Woodhams, Blanchard and Flynn PATENIEDUEEZZISYU 3,549,056 sum 2 OF 2 Fig.2.

MMWQM POWDER FEED HOPPER FOR CAPSULE-FORMING MACHINE The present invention relates to machines for encapsulation of powders.

Various types of machine having been proposed and are in use for the manufacture of filled gelatin capsules containing material in powder or granular form. For example, British Patent Specification No. 881,022 describes apparatus in which capsules are formed by bringing together capsule halves formed in two strips of gelatin or the like which pass round two revolving die rolls having matching die pockets in their surface to which suction is applied to form the capsule halves. The capsule halves formed on each die roll are filled with the aid of a feed roll mounted directly above the die roll and having charge chambers in its periphery which are filled with powder from a hopper and from which the powder is ejected into the formed capsule halves. The formed and filled capsule halves are brought into juxtaposition and are successively cut out by pressure and sealed together to form capsules.

Various types of feed rolls and hopper combinations, other than that in Pat Specification No. 881,022 have been proposed for filling the formed capsule halves, e.g. British Patent Specifications Nos. 1,109,407 and 1,118,520 describe such apparatus.

However, in all such machines, the capacity of the hopper on the feed roll is limited and the hopper has to be replenished frequently.

In accordance with the present invention there is provided a powder feed system for an encapsulating machine including a delivery hopper closed at its lower side by a feed roll having charge chambers in its-surface for the reception of charges of powder from the delivery hopper, characterized by a main hopper mounted above the delivery hopper and having one or more flexible pipes descending into the delivery hopper, means being provided for moving the lower ends of the pipes to and fro within the delivery hopper.

In this apparatus the powder in the delivery hopper closes the lower ends of the pipes and thereby terminates the supply when the powder rises above a certain level while the movement of the pipes ensures a free flow when the level in the delivery hopper falls and uncovers the ends of the pipes.

In any automatic method of filling the feed roll hopper from a main hopper, it has to be ensured that the flow or feed of powder is continuous and that the feed roll hopper is neither starved nor overfilled. It has been found, from experience, that the simplest way of accomplishing this is to mount a main hopper of a standard design approximately 1 foot above the feed roll hoppers and lower three flexible plastic tubes of k inch --1 inch bore from the bottom of the main hopper into the feed roll hoppers, so that each tube is held between two scrapers or wiper arms described in Specification No. 1,118,520 and ends approximately inch 1 inch above the surface of the end roll. With this arrangement, the scrapers will move the tube ends to and fro to assist their emptying action and the gap of inch -1 inch will prevent overfilling the feed roll hopper. In connection with overfilling, it is found that after the level of powder being emptied through the tubes reaches the lower end of the tube the powder will stay within the tube and will not flow out.

The main hopper can be of any standard design such as the vibrating type. It may also be of the type used in filling twopiece hard capsules, where a rotating arm in the bottom of a circular hopper is continuously pushing material down a tube connected to the bottom of the hopper. Generally, in hard capsule filling machines, in such an arrangement an electronic device is used to stop the rotating arm when enough powder is received in the filling machine. In the arrangement proposed, the arm rotates continuously and the level in the feed roll hopper is maintained by the gap provided between the end of the feeding tubes and the feed roll.

The invention will be described in more detail with the aid of examples illustrated in the accompanying drawings, in which:

FIG. 1 is a view in section through the feed roll hopper of one form of powder feed system in accordance with the invention,

FIG. 2 is a similar view of an alternative powder feed system in accordance with the invention, and

FIG. 3 is a partial end view of the system of FIG. 2.

The system shown in FIG. 1 comprises a feed roll hopper 1 containing a scraper frame 2 which, as described in the abovementioned Specification No. 1,1 18,520, is vibrated by a cam 3 in the form of a rotating skew-mounted disc in order to move scraper blades 4 to and fro across the periphery of a feed roll 5. The delivery hopper 1 is fed from a main hopper 6 by flexible feed tubes 7 delivering the powder 8 into the delivery hopper. The lower end of each 'feed tube 7 is located between pegs 9 on the oscillating frame 2 so that it is moved to and fro with the scraper blades.

In the system shown in FIGS. 2 and 3 the scraper blades are omitted and the lower ends of the flexible pipes 7 are sufficiently close to the feed roll 5 to assist in sweeping the powder 8 into charge chambers 9A in the feed roll. For this purpose the pipes 7 are aligned approximately with the rows of charge chambers 9A extending around the feed roll.

The pipes 7 are connected to the main hopper 6 through a rotary shutoff valve 10 having a valve body 11 rotatable by a lever 12 to prevent passage of powder from the main hopper to the delivery pipes.

The pipes 7 pass through closely fitting apertures in a transparent cover plate 13 of synthetic plastics material which covers the top of the feed roll hopper 1. The cover plate 13 has a metal frame 14 from which extends a lug 15 which engages in a cam groove 16 in a rotary cam 17. The cover plate 13 and with it the pipes 7 are thereby reciprocated, the cover plate being guided by brackets 18 engaging the frame 14.

I claim:

1. In an encapsulating machine a powder feed system comprising a delivery hopper, a feed roll closing the lower side of the delivery hopper and having charge chambers in its surface for the reception of charges of powder from the delivery hopper, a main hopper mounted above the delivery hopper, at least one flexible'pipe descending from the main hopper into the delivery hopper and means for moving the lower end of said pipe to and fro within the delivery hopper.

2. In a machine as claimed in claim 1 a scraper frame, a plurality of scrapers carried by said scraper frame, and means for reciprocating the scraper frame to move the scrapers over the feed roll, said pipe having its lower end engaged by said scraper frame for to-and-fro movement of the pipe.

3. In a machine as claimed in claim 2 the means for reciprocating the scraper frame comprising a cam.

4. In a machine as claimed in claim 1 a cover for said delivery hopper, openings in said cover for the passage of said pipes, and means for reciprocating the cover to effect to-andfro movement of the pipes.

5. In a machine as claimed in claim 4, grooves guiding said cover, a lug on the said cover, and a rotary cam having groove engaged by said lug to reciprocate the cover.

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