Ordnance, Explosives, and Related Items

Zoom Window Out
Larger Text | Smaller Text
Hide Page Header
Show Expanding Text
Print Topic
Send Mail Feedback
Share This Topic
Save Permalink URL

Navigation: Fuzes > Projectiles > United States

MTSQ, M564

clip0437

Description

Mechanical Time and Superquick Fuze M564 is used with 105mm, 155mm, and 8-in. projectiles when a choice between time and superquick action is desired.

The M564 fuze consists of head, cap, body, and delay arming mechanism (DAM). The head contains the point detonating assembly, consisting of the firing pin, support plate and two spin detents. The rotatable cap that has an engraved time scale graduated from 0 to 100 seconds (functional time range is from 2.0 to 100 seconds) contains the T103E1 Stab Primer, setting pin and hammer spring assembly. The cap and the forward portion of the body (that is engraved with a vernier scale and zero line for time settings) contain the timing movement that is basically a clock type mechanism for controlling the time of function. The movement assembly contains a trigger mechanism, firing pin and M47 Detonator. The rear portion of the body houses the M7 Relay and the DAM assembly with an RDX (Comp A5) booster pellet. The DAM contains an M17 detonator (out-of-line) and tetryl lead charge.

Functioning

The fuze is set by turning the cap clockwise which turns the movement timing disc proportionately by means of the setting pin engaged in a tab on the timing disc. Upon firing, setback deflects the hammer spring to strike the tab thus releasing the timing disc from the setting pin. As projectile spin rate increases, centrifugal force moves the detents securing the movement, and the timing mechanism begins to run. At the same time, centrifugal force starts the delay arming mechanism. The time required for arming will take the projectile at least 66 meters (200 ft) from the muzzle of the cannon. When the timing disc has rotated to the present time, a slot in the timing disc aligns with the firing arm. The firing arm enters the slot, releasing the firing pin safety plate which releases the firing pin permitting the firing pin to strike the M47 detonator and initiate the explosive train through the relay, detonator, booster lead charge and booster charge to the projectile. In the event superquick action (fired as shipped. set on “S”) is desired or if the timing mechanism malfunctions, detonation will be initiated by the SQ tiring pin striking the T103E1 stab primer on impact.

To avoid accidental functioning of PD element, do not drop, roll, or strike fuzes under any circumstances: packaged, unpackaged, or assembled to projectile, and do not strike round against breech of weapon.

This fuze contains a cocked striker.