Description
Mechanical Time Fuze M565 is used to detonate a variety of spin-stabilized projectiles for cannons of 105mm through 8-inch, except 175mm, when superquick point detonating capability is not a requirement.
The fuze consists of a solid steel head threaded into a steel lower cap containing the timing movement, and a steel body containing a detonator. A safety adapter containing a relay and a detonator in addition to an interrupter assembly is threaded into the base of the fuze body. The timing movement is a spring-driven clockwork mechanism secured in the unarmed position by setback pins and centrifugal detents. A time scale graduated from 0 to 100 seconds is inscribed on the rotatable lower cap, and a vernier scale to permit setting accuracy to 0.1 second appears on the base. The safety adapter interrupter mechanism in the base consists of two centrifugal weights which prevent alignment of the detonator with the relay until a safe arming distance of at least 200 feet from the muzzle is reached.
MT Fuze M565 is similar to MTSQ Fuze M564, except that the M565 contains neither the point detonating assembly nor the booster assembly and uses Relay M11 and Detonator XM87 in the safety adapter.
Functioning
Upon firing, setback causes the hammer spring to strike the upraised lug of the timing disk, flattening the lug and releasing the disk from the setting pin. When sufficient centrifugal force has developed, the detents holding the escapement lever of the movement assembly and the rotor of the delayed-arming safety adapter move outward, leaving the escapement components free to run. Simultaneously, centrifugal force actuates the arbor lock, which disengages from the arbor and thus releases the mainspring. As the mainspring drives the movement, the rate of rotation of the arbor and, therefore, of the timing disk is governed by the escapement through the gear train. When the notch in the rotating timing disk reaches the upright of the firing arm, the firing arm turns permitting the firing pin safety plate to swing out from under the firing pin flange, allowing the firing pin to strike the detonator. Detonator M47 initiates the explosive train through the relay and detonator to the projectile.
This fuze contains a cocked firing pin.
Physical Data
Length, overall - 5.28 in, 134.1 mm
Length, visible - 3.77 in, 95.8 mm
Hazardous Components
Detonator M47, Relay M11, and Detonator XM87.
See Also
Source(s)
TM 43-0001-28, Artillery Ammunition (chg 11, 2003)
MIL-HDBK-145, Fuze Catalog (1980)
TM 9-1300-203, Artillery Ammunition (1967)
TM 9-1385-51, Ammunition (Conventional) for Explosive Ordnance Disposal (1967)
