Patent GB-674172-A (GB)
Title: Improvements in or relating to method and machine for making capsules
IPC: A61J3/07
Filed: 1949-03-14
Abstract: 674,172. Machines for forming capsules. AMERICAN CYANAMID CO. March 14, 1949 [March 23, 1948], No. 6905/49. Class 87(ii). The doctor blade may comprise two independentlyadjustable portions so that two films of different thicknesses may be cast. The two films are separated by a rotary knife 27 and pass under a shield 29 where they are partially dried by a current of dry air. The strips are removed from the roller by a rapidly rotating paddle 33. The strip 34 passes over belt 37 or a set of rollers made of polytetrafluoroethylene or of sintered metals which are fed with oil to prevent sticking of the strip. It then passes over rollers 39, 41. 42 which reverse the strip and bring it into the same frontal plane as the lower strip 44. The lower strip 44 is fed over an oiling roller 46. Filled gelatine capsules are made in an asymmetric die system from two strips of gelatine, one of said strips being at a higher temperature than the other so that the capsules assume a symmetric shape on ejection from the dies. Molten gelatine is fed under a doctor blade 23 on to a smooth roller 24 from a thermostatically-controlled hopper 21 which rides on the casting roller by means of shoes or rollers 21s to the cavity-die roll 49. The roll 46 may be to the cavity-die roll 49. The roll 46 may be oiled by means of a rotating brush 45 or may be made of sintered brass through which the oil may be fed. The cavity die roll 49 is provided with rows of dies 51, Fig. 11, of circular elliptical, square or other cross-section each having an upstanding cutting rim 52 and a loosely fitting ejector 54. During the initial part of the filling cycle the dies communicate with a suction chest 59 in a stator 103 around which the die roll revolves, and a portion of the film is drawn into the cavity. The filling is effected from a filling hopper 69 which moves forward, positioned by pins 60, with the die roll for a short distance and is then lifted, shifted backwards and finally positioned in the next pair of pins 60 by a pin-and-slot mechanism 76. During the forward movement a number of filling heads 62 on the underside of the hopper 69 enter the dies 51 and a charge of powder is drawn into the die by a vacuum momentarily applied through passages 68 communicating with a vacuum chest 63 in the hopper 69. The vacuum is applied in a series of short bursts controlled by a microswitch 81 actuated by projections on the wheel 84. An annular plug 65 of foraminous material prevents powder from entering the passages 68. After filling, the capsule is sealed by means of the sealing strip 34, Fig. 13, which passes around an adjustable sealing roller 85. This roll may have vacuum passages 114, similar to those in the die roll 49, which help to position the strip 34. The roll may be oiled by an oiler 112. On further rotation of the die roll, compressed air is supplied to the dies from a compressed air chest in the stator 103, the ejectors 54, Fig. 14, are raised and the finished capsule ejected. Two rotary brushes revolving at high speed throw the eapsules on to a delivery conveyer 91 and the remainder of the webs is removed by rollers 93. The temperatures of the sealing and die rolls are controlled thermostatically. The position of the seal on the symmetrical capsule may be varied by differential stretching of the two films.