Patent GB-656008-A (GB)
Title: Improvements in or relating to method and apparatus for introducing strand material through a resilient substance
IPC: F42B3/198
Filed: 1948-12-22
Abstract: 656,008. Introducing strand material through a resilient substance. ATLAS POWDER CO. Dec. 22. 1948. No. 33038. Convention date, Dec. 24, 1947, [Class 108 (iii)] [Also in Group XXI] A method for introducing strand material through a resilient substance comprises inserting a needle, and a sleeve fitting around the needle, through the substance, withdrawing the needle from the sleeve and inserting the strand material into the sleeve and withdrawing the sleeve from the substance. As applied to the insertion of two wires in the sealing plug of a blasting cartridge (see Group XXI) a pair of needles 65, 67 are carried by a holder 43 which may be raised and lowered by a handle 37 and associated rack and pinion 35, 39. A resilient plug 21 for an electric blasting cap is positioned in a recess A in a main frame 14. Sleeves 45, 47 are slidably mounted in bores 49, 51 disposed in the frame 14 in axial alignment with the needles 65, 67 respectively, and opening into the recess A. The sleeves 45, 47 are rigid with a member 23 slidably mounted in a bore B in the frame 14 by the action of a handle 25, downward movement being limited by a stop 33. The recess A is normally covered by members 107, 108, Fig. 9, which are pivoted to the frame 14 at 111 and may be moved to an uncovering position by handles 109, 110 against a spring 125. The members 107, 108 are formed with respective recesses which-unite in the former position of the members to provide apertures 129. 131 in axial alignment with the needles 65, 67. The apertures 129, 131 each have an upper flared portion and a lower cylindrical portion to receive the respective sleeve 45 or 47. Each needle 65, 67 is shouldered above the point, the diameter of the upper cylindrical portion being equal to the external diameter of each of the sleeves 45, 47. In operation, the handle 37 is operated to project the needles through the plug 21 and into the sleeves 45, 47, until the shoulders on the needles abut the sleeves. The handle 25 is then raised to project the sleeves upwardly through the holes in the plug formed by the needles, the latter being driven upwardly thereby. Movement of the sleeves is limited by engagement with the recesses 129, 131. The needles are then fully retracted by the. handle 37 and respective wires are inserted in the portions of the sleeves within the plug. The sleeves are then retracted by the handle 25 and the members 107, 108 are moved apart to enable the plug 21 to be removed. In a modification, Figs. 1-7 (not shown), the needles have no shoulder and are of a maximum diameter equal to the bore of the sleeves. After the needles have been projected into the plug the sleeves are also projected therein so as to surround the respective needles which are afterwards withdrawn by the handle 37. In this construction the holder 43 has limited sliding movement relative to the rack 39, against the action of a coiled spring. In a further modification, Fig. 10 (not shown), the handle 37 and needle mounting assembly are mounted below the recess A (on the same side as the handle 25 and sleeves 45, 47) and the needles are initially projected upwardly through the sleeves on their travel towards the plug 21. In this modification the member 23 is mounted with provision for lost motion relative to the handle 25 so that it is engaged by the upper surface of the holder 43 to project the sleeves into the plug 21 (following the needles) by the action of the handle 37. The plug may be of natural, or synthetic rubber e.g., Neoprene "Buna S", "Buna N " (Registered Trade Marks), or of plastic material, e.g. plasticized polyvinyl chloride resin. Such materials.should have a shore Durometer hardness of between 30 and 90. The invention may be applied to resilient material which is already provided with holes.