Patent GB-781043-A (GB)
Title: Improvements in or relating to machines for manipulating cut tobacco
IPC: A24C5/34
Filed: 1951-10-25
Abstract: 781,043. Beta-ray gauges. MOLINS, D. W., and MOLINS MACHINE CO., Ltd. Oct. 3, 1952 [Oct. 25, 1951], No. 25029/51. Class 40 (3). [Also in Group VI] In a beta-ray gauge which determines the mass of a stream of tobacco the performance of the apparatus is checked when desired by means of a device for substituting a known mass between the radiation source and the ionization chamber. Several known masses may be arranged in a frame, means being provided for introducing any one of them into the radiation path. As shown, the stream of tobacco under test passes between jaws 112, 113 which are heated to prevent condensation of the gumming moisture and on one side of which is positioned the radio-active source (Strontium " 90 ") in a box 111 and on the other an ionization chamber in a housing 110. The chamber 110 is provided with a wire mesh guard 114 and the box with a window. On the lower edge of chamber housing 110 is pivoted, on a hinge bracket 121, a screen holder 122. The screen holder is grooved and carries a screen frame in which are screens 125, 126, 127 and an aperture 135. The frame may be adjusted vertically to position either this aperture or any one of the screens in the path of the rays passing through the tobacco stream by means of toothed rods 128 at the side of the frame which are adjusted by pinions rotated by a knob 129. The shaft 131 which carries the pinions is provided with flats 133 which engage stiff springs 134 so as to locate the appropriate screen accurately. The distance of the radio-active source from the chamber may be adjusted by a bracket 152 to which the source holder is attached and which carries a thickened portion 153 through which two screws 154 are threaded. The screws are rotated by a knob 159 and bevel gears 155, the position of the source being indicated by a pointer 160. The ionization chamber is pivoted into position and locked by a bracket 151. When it pivots out of position about axis 146, links 150, 149 attached to it move a shield 147 in front of the radiation source, to prevent harm to an operator. In a modification (Fig. 7, not shown), the tobacco stream is not in paper and passes over a flat surface and between sideplates. The ionization chamber and source are mounted above and below the tobacco stream respectively, and the protective screen is covered to slide horizontally in front of the source when the chamber is pivoted back, by means of toothed wheels mounted on the axis about which the chamber pivots co-operating with teeth on the shield. In a further modification (Fig. 9, not shown) the source and chamber are reciprocated vertically at intervals possibly by a cam mechanism so that a screen above the tobacco stream is substituted in the radiation path for that stream. Cigarette gumming and feeding arrangements (Fig. 6).-When the apparatus is to be tested the cigarette rod is deflected by the operator in known manner and shutter 136 is pressed into position over an aperture in an oblique guardplate 137 by means of a handle 145 with a catch which engages a notched plate attached to the shutter. When the catch is released a spring 142 swings the shutter clear of the aperture. A heater mechanism 10 which may be swung clear, as shown, is provided to seal the overlap of the cigarette rod. The pivot 138 of the heater carries a crank mechanism 140 to one end of which spring 142 is attached. Thus when the heater is swung clear of the rod the tension in the spring is released and the shutter 136 drops in front of the aperture in screen 137. Specifications 684,503, 781,041, [Group XXXV], and 781,042 are referred to.