Pd Fuze Functioning Superquick

UNO proper shipping name-----Fuzes, detonating

Explosive Components:


Detonator M50, Relay M7 and Detonator M49.


Premature functioning downrange may occur if fuze is fired in rainfall.

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


SC 1340/98-IL TM 9-2350-311-10 TM 9-1015-203-12 TM 9-1015-234-10 TM 9-2300-216-10 TM 9-1015-215-10

Ammo 105mm

Type Classification:

Std AMCTC 268 dtd 1962.


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 Ml7 detonator (out-of-line) and tetryl lead charge.


'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.

Tabulated Data:


Temperature Limits:


Lower Limit ---------------------------------------------------40OF (-40OC)

Upper limit------------------------------------------------+125F: (+52OC)


Lower limit ------------------------- -80OF (-62.2OC)

(for a period of not more than 3 days)

Upper limit ------------------------- +160OF (+71.1 OC)

(for a period of not more than 4 hr/ day)

*Packing ------------------------------- X fuzes in metal containers, 2 containers in wire-hound box

*Packing Box:

Dimensions ------------------------- 14.5/8 x 12-13/16

*NOTE: See DODC Consolidated Ammunition Catalog for complete packing data including NSN's.

Shipping and Storage Data:


UNO proper shipping name-------- Fuzes, detonating

Explosive Components:

Detonator M47, stab primer T103, Relay M7, Detonator M17, tetryl booster lead charge, and RDX/Comp A5 booster charge.


Fuzes manufactured prior to January 1970 must be set for 90 seconds if super-quick (impact) action only is desired. Fuzes manufactured from January 1970 on. could be set on either "S" or "90 seconds" if superquick (impact) action is desired. However, current doctrine dictates that all M564 fuzes, regardless of manufacture: date. must be set on 90 seconds if superquick (impact) action is desired.

Premature functioning may occur downrange when the fuzes are fired in rainfall.

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.


TM 9-1025-211-10 SB 700-20 SC 1340/98-IL TM 9-1300-251-20 TM 9-2300-216-10 TM 9-1025-200-12&P TM 9-1015-203-12 TM 9-1015-234-10 TM 9-1300-251-34 TM 9-2350-304-10 TM 43-0001-28-4 TM 43-0001-28-5 TM 43-0001-28-6 TM 43-0001-28-7 TM 43-0001-28-8 TM 43-0001-28-9 TM 43-0001-28-10 TM 9-2350-311-10

M577a1 Fuze

Type Classification:

M577 Standard A MSR 05736060 March 73. M577A1 Standard A, MSR 06846012 June 84. M577 Standard B. MSR 06846012 June 84.


Mechanical Time and Superquick (MTSQ) Fuze M577A1/M577 is used with 4.2-inch and 105mm cartridges, and 155mm and 8-inch projectiles. It is used with projectiles carrying pa -loads that are expelled during projectile flight (airburst). See cartridge/projectile fuze combination charts in Appendix A for current usage.


The fuze contains a mechanical clockwork timing mechanism that can be set to function at any time from 2 to 200 seconds. The fuze is set with M35 fuze setter or flat screwdriver.

The setting key is at the nose of the fuze, and the time to be set is viewed on three dials through a window in the side of the ogive. The dial closest to the nose indicates hundreds of seconds, or a triangle for a non-time setting. The second dial indicates tens of seconds, and the third dial indicates seconds and tenths of seconds. All setting are made by reference to a hairline visible through the window

The timing mechanism and point detonating element are contained in the ogival nose section of the M577. The M577A1 does not contain the point detonating element, but rather utilizes the safe separation assembly as an iner-tial element to initiate impact function. On impact, the safe separation assembly slides forward and the detonator in the rotor is stabbed by the firing pin in the trigger mechanism. The safe separation device and trigger are contained in the fuze body. The timing mechanism and safe separation assembly are prevented from operating before adequate projectile spin is attained by centrifugally operated lock pins and the centrifugal detents are further restrained by setback pins. The safety and arming mechanism includes a spin-activated rotor to block the detonation train prior to arming. Movement of the arming mechanism is interlocked by a scroll fol- lower in the timing mechanism which also restrains the firing pin.

The M577 fuze has an aluminum ogive with an anodized black coating and a steel lower body. The M577A1 fuze has a zinc ogive but earlier manufactured A1 fuzes have black paint coated ogives while later manufactured A1 fuzes have chromate finished (gold color) ogives. The M577A1 ogive also has different wrench slots though the same wrench is used. The lower body is aluminum with chromate coating.


Setback and centrigual forces from weapon firing acting on spring, lock, and spin detents allow the fuze to arm and function at its preset time or if the setting is point detonating, on impact with the target. The safe separation device is designed to provide the safety and arming features of the fuze. A rotor, which carries a detonator, is held out of line with respect to the firing pin by two spin detents, and further restrained by the interlock in the trigger, A properly sequenced firing environment (setback and spin) will actuate the interlock and detents allowing the rotor to rotate to the inline (ARMED) position. When the setting is point detonating (<98) or for a time less than 4 seconds, the rotor is released almost immediately. However, when set for a longer time, the rotor is not released by the interlock until approximately 3 seconds before the set time, thus providing overhead safety (because of this delay, when the fuze is set for airburst and the projectile impacts before the time setting, the fuze may not function). Motion of the rotor is controlled by a runaway escapement with its arming distance dependent on the subjected spin rate. Spin rate is a function of the characteristics of the weapon/propelling charge combination.

A difference in functioning must be noted in the point detonating mode between the M577A1 and the M577. On impact, a point detonating element in the nose initiates the explosive train of the M577 fuze. For the M577A1 fuze, on impact the safe separation device will shale forward and the rotor detonator will be stabbed by the firing pin in the trigger mechanism to activate the explosive train of the fuze.

Tabulated Data:

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  • Tommy
    What is a superquick fuze?
    1 year ago

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