Cutaway model of two PRB mines with a kinship in design. The Belgian PRB (Poudreries Réunies de Belgique) company was an ammunition factory that was closed in the early 90’s of the last century after an illegal arms delivery scandal with Iraq.
Left, trip flare M70A5 with pull fuze Nr.410, at the right AP mine Nr.413 with pull fuze Nr.410.
Functioning of pull fuze Nr.410:
The fuze housing is made of PVC. It houses a partially tensioned firing pin. Near the top of the firing pin, a groove is machined. A collar with a radial hole is placed over the top of the firing pin. Two steel balls are placed in the radial hole -one on each side of the firing pin- and in the groove of the firing pin. As long as the collar is in the narrow part of the fuze body which forces the balls inward, the firing pin is arrested by the collar. Four steel wires with a pull ring at the end emerge from the top of the collar, and are meant to be connected to the trip wires. As soon as one pulls the trip wire, the horizontal movement of the trip wire is translated into a vertical movement, pulling the collar upward. With the collar moving upward into the wide part of the fuze body, both steel balls can move outward, releasing the firing pin. While moving upward, the firing pin spring is further tensioned.
The force to activate the fuze is between 2 to 5 kg.
An aluminium strip with a pull ring is placed into a slot above the collar; this is the transport safety. As soon as the mine is placed and the trip wires are attatched the strip is pulled out and the mine is armed.
On the outside of the fuze body four hooks are machined, over which the rings on the steel wires are hooked. This is done for transport purposes. When placing the mine, the required number of rings are ‘unhooked’.
So, all rings hooked as in the pictures below is the situation just prior to attaching trip wires.
The pull fuze No.410 is screwed in the top cover of the trip flare. The firing cap is incorperated in the top cover of the flare.
When the pull fuze No.410 is used in the anti personel mine Nr,413 it has an extra step at the base to house the duplex detonator.
The trip flare M70A5 (named M109 when produced in portugal) consists of an aluminium bushing filled with magnesium compound. The top layer is the ignition layer, ignited by the firing cap (red). On top of the flare body a cap is placed, held in place by means of a seam. When the flare is ignited, the gasses of the ignition layer push off the top cover and the flare starts to lighten up the surrounding area.
Complete length (with white protectice cap / wire spool) : 205mm
Length flare without cap (with fuze) ; 190mm
Diameter : 50mm (white cap 60mm)
Weight : 225 grams of which 202 mm magnesium
The ‘mine AP Nr.413’ (M421 when produced in Portugal) has a bottle shaped plastic body with a sleeve of notched square wire 3x3x3mm, wound around the straight part of the mine body.
The mine is filled with 100 grams of Comp.B (TNT/RDX), a booster of three stacked 2,25 grams pellets of tetryl (orange) are placed in the center of the Comp.B charge below the detonator.
The effective range is approximately 15 meters.
Complete length mine (with fuze) : 180mm
Length mine body : 140mm
Diameter mine : 46mm
Weight mine : 640 grams
The mine has been found in Chad, Lebanon, Rwanda and the western Sahara.
Regards, DJH
Left, trip flare M70A5 with pull fuze Nr.410, at the right AP mine Nr.413 with pull fuze Nr.410.
Functioning of pull fuze Nr.410:
The fuze housing is made of PVC. It houses a partially tensioned firing pin. Near the top of the firing pin, a groove is machined. A collar with a radial hole is placed over the top of the firing pin. Two steel balls are placed in the radial hole -one on each side of the firing pin- and in the groove of the firing pin. As long as the collar is in the narrow part of the fuze body which forces the balls inward, the firing pin is arrested by the collar. Four steel wires with a pull ring at the end emerge from the top of the collar, and are meant to be connected to the trip wires. As soon as one pulls the trip wire, the horizontal movement of the trip wire is translated into a vertical movement, pulling the collar upward. With the collar moving upward into the wide part of the fuze body, both steel balls can move outward, releasing the firing pin. While moving upward, the firing pin spring is further tensioned.
The force to activate the fuze is between 2 to 5 kg.
An aluminium strip with a pull ring is placed into a slot above the collar; this is the transport safety. As soon as the mine is placed and the trip wires are attatched the strip is pulled out and the mine is armed.
On the outside of the fuze body four hooks are machined, over which the rings on the steel wires are hooked. This is done for transport purposes. When placing the mine, the required number of rings are ‘unhooked’.
So, all rings hooked as in the pictures below is the situation just prior to attaching trip wires.
The pull fuze No.410 is screwed in the top cover of the trip flare. The firing cap is incorperated in the top cover of the flare.
When the pull fuze No.410 is used in the anti personel mine Nr,413 it has an extra step at the base to house the duplex detonator.
The trip flare M70A5 (named M109 when produced in portugal) consists of an aluminium bushing filled with magnesium compound. The top layer is the ignition layer, ignited by the firing cap (red). On top of the flare body a cap is placed, held in place by means of a seam. When the flare is ignited, the gasses of the ignition layer push off the top cover and the flare starts to lighten up the surrounding area.
Complete length (with white protectice cap / wire spool) : 205mm
Length flare without cap (with fuze) ; 190mm
Diameter : 50mm (white cap 60mm)
Weight : 225 grams of which 202 mm magnesium
The ‘mine AP Nr.413’ (M421 when produced in Portugal) has a bottle shaped plastic body with a sleeve of notched square wire 3x3x3mm, wound around the straight part of the mine body.
The mine is filled with 100 grams of Comp.B (TNT/RDX), a booster of three stacked 2,25 grams pellets of tetryl (orange) are placed in the center of the Comp.B charge below the detonator.
The effective range is approximately 15 meters.
Complete length mine (with fuze) : 180mm
Length mine body : 140mm
Diameter mine : 46mm
Weight mine : 640 grams
The mine has been found in Chad, Lebanon, Rwanda and the western Sahara.
Regards, DJH
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