US 3579960 A
Description (OCR text may contain errors)
United States Patent 1 Inventor Maharaj Krishen Mehta Lakeside, Cardiff, Wales App]. No. 805,687 Filed Mar. 10,1969 Patented May 25, 1971 Assignee P. Leiner & Sons (Encapsulations) Limited Tretorest, Glamorganshire, Wales Priority June 26, 1968 Great Britain 30567/68 POWDER-ENCAPSULATION MACHINE 5 Claims, 2 Drawing Figs.
US. Cl 53/184 Int. Cl.... B65b 47/02 Field of Search 53/28, 30,
 References Cited UNITED STATES PATENTS 1,970,396 8/1934 Scherer 53/18OX 2,152,101 3/1939 Scherer 53/184X 2,497,212 2/1950 Donofrio 53/180X Primary ExaminerTheron E. Condon Assistant Examiner-E. F. Desmond Attorney-Woodhams, Blanchard and Flynn ABSTRACT: Apparatus for forming filled gelatine capsules having two pocketed die rolls and a heater block supported between the die rolls to heat the gelatine ribbons as they appreach the nip of the rolls, the side faces of the heater block being spaced from the ribbons to heat them by radiation. A tip member for heating the ribbons by direct contact immediately before their passage through the nip can be freely suspended from the heater block. l
POWDER-ENCATION MACHINE The present invention relates to a capsule-forming machine for the encapsulation of powders.
Various types of machine have been proposed and are in use for the manufacture of filled gelatine capsules containing material in powder or granular form. For example, British Patent Specification No. 881,022 describes one type of encapsulating apparatus in which capsules are formed by bringing together capsule halves formed in two strips of gelatine 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. In order to obtain satisfactory sealing of the two formed and filled capsule halves, it is necessary to heat the gelatine ribbons slightly. For this purpose cartridge heaters are utilized; which are fitted in the shafts supporting the die rolls.
The temperature of the ribbons is thus raised to that required for sealing as soon as the ribbons contact the die rolls and prior to their deformation into capsule halves. With standard grades of gelatine the elasticity of the sheet at the raised temperature is less and the capsules do not assume regular shapes after release of vacuum and sealing. One way of overcoming this difficulty is'to use a higher grade of gelatine and a thicker ribbon but this is more expensive.
In another type of encapsulating machine for encapsulating liquids or pastes the filling is forced betweentwo gelatine ribbons immediately before they pass through the nip of two pocketed die rolls, the feeder head being located between the two die rolls and resting on the two ribbons and fitted with cartridge heaters to raise the ribbons to sealing temperature. It has been found that if such a heated feeder head is used in a powder-encapsulating machine in which capsule halves are formed by the application of suction to the die roll the results are not satisfactory since the capsule halves are not properly sealed together.
In accordance with the present invention there is provided a powder encapsulation machine of the type disclosed in British Specification No. 881,022 and having a pair of die rolls over which gelatine ribbons are passed, the die rolls having registering cavities in their peripheries for the formation of capsule halves in the ribbons by the application of suction, and means for delivering powder into the formed capsule halves in a conventional manner when the capsule halves are at the top of the die roll (see FIG. 3 of British Specification No. 881,022), and wherein a heater block is located between the die rolls to raise the temperature of the gelatine ribbons as they approach the nip of the rolls where the capsule halves are sealed together, the heater block being so positioned and dimensioned that there is a gap between the gelatine ribbons and the side faces of the heater block. Preferably the heater block has curved side faces conforming to the curvature of the die rolls and meeting along an edge running the full width of the ribbons, the gap being thus of uniform width over the whole area of each side face of the heater block. The ends of the block may rest on the ends of the die rolls outside the area covered by the gelatine ribbons.
With this arrangement of a heater block spaced from the gelatine ribbons so that the heating takes place by radiation it is found that satisfactory sealing can be achieved and because the heating is only carried out close to the point of sealing and after formation of the capsule halves, the capsules produced from standard grades of gelatine are of regular shape.
A preferred construction includes a tip member for heating the gelatine ribbons by direct contact immediately before their passage through the nip of the rolls, the tip member being so mounted as to be freely movable away from the rolls by any irregularity in the thickness of the ribbons with which it is in contact.
By this means the heat can be more efficiently conveyed to the gelatine ribbons near the point at which it is required, without the setting up of undue stress by contact with the ribbons since the tip member can be of relatively light construction and will float on the ribbons.
The invention will be described in more detail with reference to the accompanying drawings, in which:
FIG. 1 is a schematic cross section of the die rolls, heater block, and tip member of a machine in accordance with the invention, and
FIG. 2 is a side elevation of the heater block and tip member.
The die rolls 1 are supported on shafts 2 and are of conventional construction with pockets in their peripheries and means for applying vacuum to the pockets near their topmost position and for releasing the vacuum as the pockets pass close to corresponding pockets of the other roll for the sealing together of the capsule halves and the severing of the sealed capsules. Conventional filling means are located adjacent the top of the die rolls for filling the capsule halves therein. The above described structure is conventional and well known, being described in above-mentioned Specification No. 881,022.
According to the present invention, a heater block 4 is disposed closely adjacent the nip between the die rolls 1. Cartridge heaters 3 located in passages in the heater block 4 provide the heat for raising the gelatine ribbons to the sealing temperature. The end sections 5 of the heater block 4 rest on the ends of the die rolls 1 but the side faces 6 are recessed or v machined out to leave a gap between these faces and the gelatine ribbons 7.
As shown in FIG. 1, the heater block 4 is wedge-shaped with a generally triangular cross section and has curved side faces which meet along a bottom edge of the block. The side faces 6 conform to the curvature of the die rolls and are spaced from the surface of the rolls and are spaced from the surface of the rolls by an amount sufficient to ensure about one-sixteenth inches clearance from the surface of the ribbons 7.
As seen in FIG. 2 the heater block 4 is suspended from a beam 8 by means of hooks 9 which engage lugs 10 on the block and which are adjustable in height by means of nuts IL A solid heater block having the form described with side faces spaced from the ribbons so that heat is transmitted by radiation from the block to the ribbons can be used successfully. However, in the preferred construction illustrated means are also provided to transfer heat to the ribbons by direct conduction.
The lower part of the heater block 4, adjacent the nip of the die rolls 1, has grooves 12 extending along its length and slots 13 passing transversely through its body at each end. A tip member 14, fabricated from metal sheet to a V-shape with outwardly curving sides to conform to the gelatine ribbons 7 resting on the die rolls, has upper edges which are vertically slidable in the grooves 12. The upper edges of the tip member 14 are connected by two transverse pins 15 which are disposed in the slots 13. The pins 15 are mounted on the lower ends of screws 16 adjustable by wing nuts 17 to allow the height of the tip member 14 to be adjusted. The screws 16 and wing nuts 17 serve as suspension members and determine the lower limit of movement of the tip member 14 while allowing upward movement of the tip member.
As shown in FIG. 1, the tip member rests in contact with the gelatine ribbons 7 immediately before they pass through the nip of the die rolls and it serves to heat the ribbons by conduction, deriving heat from the heater block partly by conduction through the mounting and partly by radiation and convection. If there shouldbe any irregularity in the thickness of the ribbons the slots 13 allow the tip member 14 to float freely to accommodate variations in thickness. The weight of the tip member 14 is small and thus very little pressure is exerted on the gelatine ribbons. The tip member 14 is preferably coated with a thin coating of polytetrafluoroethylene to allow free movement of the gelatine ribbons over its surfaces without preventing the flow of heat to the ribbons.
1. In an encapsulation machine having a pair of rotatable die rolls over which gelatine ribbons are passed, the die rolls having registering cavities in the peripheries thereof for permitting formation of capsule halves from the ribbons, the machine further having means for applying suction to the cavities to form capsulehalves in the gelatine ribbons and means for delivering powder into'the formed capsule halves, the improvement comprising heater means for heating the ribbons by radiation, the heater means including a heater block located between the die rolls to raise the temperature of the gelatine ribbons as they approach the nip of the rolls whereby the capsule halves are sealed together, the heater block having side faces conformed to the curvature of the die rolls and means mounting the heater block with the side faces spaced from the ribbons, whereby the ribbons are heated by radiation from the block, and a tip member mounted on the heater block to rest on the gelatine ribbons immediately before they pass through the nip of the rolls for heating the ribbons by direct contact, and means mounting the tip member for allowing it to be displaced by any irregularity in the thickness of the ribbons with which it is in contact.
2. A machine according to claim 1, in which the tip member is of sheet metal formed to a V-shape with outwardly curved sides to conform to the gelatine ribbons resting on the die rolls.
3. A machine according to claim 2, in which the V-shaped tip member has upper edges which are vertically slidable in grooves in the heater block.
4. A machine according to claim 3, in which the upper edges of the tip member are joined by transverse pins passing through vertically elongated slots in the heater block and carried by suspension members determining the lower limit of vertical movement of the tip member.
5. A machine according to claim 1, in which the heater block has end sections which rest on the die rolls and the side faces are formed by recesses which accommodate the gelatine ribbons.