Bofors ogival breech diagram
Lt-Colonel William H Tschappat, Ordnance Department, USA. "Text-Book of Ordnance and Gunnery". published by John Wiley & Sons, New York, 1917. Page 301.
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Diagram depicting Bofors ogival screw breech block. Depicted is US 6-inch gun.
Text : The block, b, is ogival in shape and has six threaded and six slotted sectors. With the ogival shape a very small retraction to the rear is necessary before the block may be swung open. In the 6-in. gun this retraction is 1.2 ins., just sufficient to withdraw the obturator o from its seat in the bore. The block is supported when the breech is opened by the block carrier c provided with a central tube which embraces a spindle s formed in the block.
The mechanism is actuated by means of the lever l (see figure 111 File:Bofors ogival breech operation photos.jpg) which is attached to the lower end of the hinge pin. A spool p mounted on the hinge pin has teeth cut near its lower end which engage in the rack r. The rack slides in a horizontal groove cut in the block carrier c, and the teeth at its left mesh with corresponding teeth on the hub of the breech block which projects through the rear face of the carrier.
When rotation of the block is completed a lug, u, (see figure 110 File:Bofors ogival breech operation photos.jpg) on the spool engages in a slot at the rear end of the block and translates the block slightly to the rear. Before this translation is complete the block carrier is unlocked from the gun, and swings to the rear with the block, fully uncovering the bore. The loading tray, shown in figure 113 (see File:Bofors ogival breech operation photos.jpg) the purpose of which is to protect the threads of the breech from injury as the shot is put into the bore, remains permanently in the breech. When the block is entered and rotated the tray is pushed aside by the threads on the block until it covers the slotted sector. On opening the block it is brought back into the position shown.Mer information om licensen för bilden finns här. Senaste uppdateringen: Sun, 07 Apr 2024 05:51:13 GMT