The D.Z. 35 push igniter is cylindrical in shape, and designed for use with improvised mines, etc. The safety arrangement is a safety bolt which passes diametrically through the external portion of the plunger, thereby preventing the latter being pushed in to fire a cap. It is reported that a pressure of between 130 lb. and 165 lb. is required to ope-rate the igniter. A specimen tested, functioned at a pressure of approximately 150 lb. The overall length is 2.67 inches and the diameter of the body 1.25 inches. It is vanished a copper colour.

Another type of D.Z. 35, made of brass, similar in action but rather different in construc-tion and with a body diameter of 1 inch, is reported to be in existence. The pressure ne-cessary to fire this type is considerbly less than that required to function the one des-cribed above.

The aluminium body is a cylindrical casing shaped at the top to form an internal flange, and screwthreaded internally at its lower end to receive an aluminium closing plug with central channel contains the percussion cap. The central channel extends into a projec-tion formed in the base of the plug for the insertion of a  detonator when required. The projection is screwthreaded externally for insertion in the charge container and is closed by a screwed transit cap. The plug, when screwed home, is secured by a grub screw which passes through the wall of the cylindrical body. A thin cardboard washer fits on the underside of the plug and surrounds the projection.

Above the plug, is a sleeve with an external flange at its base end which forms a seating for the lower end of the steel spiral supporting spring surrounding its smaller diameter. Internally, the sleeve at its upper end acts as a guide to the plunger, its lower end is of greater diameter to allow the balls to be forced out-wards when pressure is applied ot the plunger.

The upper end of the supporting spring bears against the external flange of an aluminium plunger which is assembled from the inside of the casing, so that its top end protrudes from the case, whilst the lower end fits into the sleeve. The upper side of the flange bears against the underside of the internal flange at the top of the case and limits its upward movement. The protruding portion of the plunger is screwthreaded externally to receive a flat circular screwed head with milled edge. An aluminium safety bolt with split rings at one end and a retaining nut at the other, passes through a horizontal channel in the plunger below the milled head. A groove, semi-circular in section, is formed in the centre of the bolt to engage a  spring-loaded ball located in a vertical channel in the up-per end of the plunger. The ball and spring are retained in position by a screwed plug.

The plunger is recessed from the base to accommodate the striker and its steel spring, and has two radial holes each locating a steel ball which engage a circumferential groove in the striker.

The steel striker has a stem formed at its upper end, over which its steel spring is as-sembled. The spring is held under compression between a flange on the striker and the upper end of the recess. A circumferential groove, with the upper side inclined is formed in the striker body to engage with the two steel balls.

To arm the igniter the safety bolt is withdrawn by removing its retaining nut and pulling the bolt out of the plunger against the resistance of the spring-loaded ball.

When pressure is applied to the plunger it is forced into the body against the resistance of the supporting spring. When forced down sufficiently, the steel balls lose the support of the smaller diameter in the sleeve and are pushed outwards by the inclined surface of the striker groove under pressure from the striker spring, which also drives the striker on the cap assembly.

Fig. 1