GB513821A - An improved clip for holding a detonator in a blasting charge - Google Patents

Abstract

513,821. Blasting-cartridges, ROLFES, Ltd., and ROLFES, F. H. March 22, 1939, No. 9046. [Class 9 (i)] A clip for holding detonators in blasting charges comprises means connected to the detonator casing and/or to the fuze or electric wires,' adapted to be passed through the cartridge so that part of the said means projects beyond the cartridge and can be bent against the adjacent surface thereof, in order to resist or prevent retraction 'of the detonator by a pull on the said fuze or electric wires. As shown in Fig. 1, the clip comprises two complementary parts 1, 2 of half-ring section which are held about the detonator 3 by a ring 4 and are provided at their lower ends with tapered prongs 5, 6 having weakened zones 7, 8. In use, the clip and detonator are thrust axially downwards through the cartridge 10 until the prongs 5, 6 project from the lower end thereof whereupon the prongs are bent outwardly about their weakened zones so as to occupy the positions shown in dotted lines. Fig. 2 shows a modification in which the detonator 3 is inserted obliquely through the cartridge 10, the clip comprising a hook member 12 formed integral with a depending member 13 having flexible lugs 14, 15 whereby it may be crimped to the detonator, with or without the use of a ring 4. According to a further modification, Fig. 3, the clip consists of a flexible strip 17 which is pointed at its lower end and is formed at the top ,with lugs 19 adapted to be crimped around the detonator 3. When the extemity 18 of the strip 17 projects beyond the side of the cartridge, it is bent upwards into the position shown so as to constitute a hook preventing retraction of the detonator. A modification of this construction is described, Fig. 4 (not shown), in which the strip lies along the lower side of the detonator and is initially given an S bend so that it extends below the end of the detonator and has its point brought substantially into alignment with the axis thereof. After insertion in the cartridge, the pointed end of the clip is bent upwards as before against the side of the cartridge. Fig. 5 shows a further modification in which the clip consists of a strip 23 of arcuate cross - section throughout its upper part, an S-shaped bend 24 being provided adjacent the end of the detonator. At this bend, the metal of the clip is'compressed together as shown at 25 whilst, towards the end of the clip, the metal is flattened to provide a straight tip 26 which can be easily bent up about the line A - A in order to form a hook which will grip the cartridge.