Patent GB-191129376-A (GB)
Title: Improvements in or relating to Apparatus for Sweeping for Marine Mines.
IPC: B63G7/04
Filed: 1911-12-30
Granted: 1912-12-23
Abstract: 29,376. Bohn & Kõhler. Dec. 31, 1910, [Convention date]. Recovering mines.- Relates to mine-sweeping apparatus comprising a supporting-buoy and a sinker suspended therefrom and having one end of the sweep attached to it. The sweep is led in the form of a circular arc to a second similar sinker, the apparatus being towed by two launches. According to the present invention, one of the sinkers has detachably connected thereto the sweep and a grapnel used subsequently for destroying the mooring cable, the grapnel being constructed so as to cut the cable or destroy it by ,means of an explosive charge. The buoy is also provided with an electric-lamp signalling- device to indicate that the mooring - cable is about to be destroyed. The general arrangement is indicated in Figs. 1 and 2. Each launch has a winch with two drums separately operable. The buoy line M is wound on one drum and the sweep line N on the other. When the sweep H meets the mooring-cable of a mine, the coupling at F is released. The continued pull of the other launch on the sweep H causes the grapnel G to engage the mooring-cable, and to fire the contained charge, and also by the pull at the switch S to close the circuit for the lamp B. The sinker, shown separately in Fig. 3, has ears 2, 3, for the attachment of the line N, an ear 1 for attachment of the line K leading to the buoy A, and a detachable coupling for the sweep H comprising jaws 5, 6 pivoted at 7 to a spring-controlled rod 8 and having projections 9, which engage the head 10 until the tension in the sweep H overcomes that of the spring 12, the jaws then opening to release the sweep. The sinker also carries a drum 14 upon which the cable P, Fig. 1, is wound. The grapnel, shown separately in Figs. 7 and 9, is connected by an eye V and cable O to a supplementary float C, by means of an eye W and cable L to the sinker and cable P, and by a cable J to the sweep H, and comprises a movable part which slides back when the grapnel meets the mooring-cable of a mine, thus releasing a second part normally locked to the grapnel and used for dragging the grapnel by means of the eye W and cable L. The separation of the parts explodes the charge h. The two parts a, b of the grapnel are provided with arms a', b<1> for guiding the grapnel to the mooring-cable, and the parts a, b, c, d, Fig. 9, constitute a cylindrical chamber for the charge h and are bolted together by bolts c. The cable J is attached to a clamp i which is forked at i<1>, i<2> to pass through the members c, d; recesses i<3> in the parts i<1>, i<2> engage pivoted catches, k<1>, k<2> which, at their inner ends engage inclines m<1> in a block m screwed to the plate r and projecting through a guide sleeve o and prevented from moving therein by a shearing-pin p. When the grapnel encounters a mooring-cable, the arms a<1>, b<1> guide the cable to the front of the charge i, the pin p is sheared by the pull in the cable J, relative movement of the charge h and casing causes the catches k<1>, k<2> to be disengaged from the recesses i', the continued pull on the line J causes the fork i<1>, i<2> to leave the grapnel, and by means of a pin t connected to plates s carried by the fork and passing through the loop u of the ignition wire of the detonator, the wire is pulled out, thus exploding the charge. The buoy A carries an electric lamp B, which is brought into operation when the pull in the line 0 withdraws the insulating-member 110, Fig. 5, from the two parts 108, 109 of an electric switch in the circuit 104, 106, 107 of the battery 105.