M 54 TSQ Fuze
1. IDENTIFICATION. Figure 1 shows the appearances and dimensions of the M5,M54, and M55A3 fuzes. The M5 fuze consists of an M54 fuze fitted with an adapter for use with some 4.2-inch mortar rounds. The M55-series fuzes are identical in every respect with the M54 fuze except that the M55-series fuzes are assembled to
an M21-series booster.
a. Type. These are manually armed, setback-initiated delay fuzes which incorporate a centrifugally armed, impact-fired superquick feature. They are called time and superquick (TSQ) fuzes.
b. Painting and Markings. The fuzes are unpainted. The fuze designation, manufacturing and loading information, and the time setting mark are stamped into the body. Time graduation marks in 0.2-second increments, with each second numbered, are stamped into the movable time ring along with an index mark and the
letter S.
2. DESCRIPTION. The heads and bodies of the fuzes are aluminum. The time rings are brass.
3. HAZARDOUS COMPONENTS. Each fuze contains a primer, a black powder time train, and a detonator consisting of primer mixture and lead azide, each weighing less than 1 gram, and a 3-gram, black powder magazine charge. The adapter of the M5 fuze contains 18 grams of tetryl and 1 gram of lead azide. The booster (M55 series fuzes only) contains a lead azide-tetryl detonator and tetryl lead, each weighing less than 1 gram, and a 22-gram tetryl booster charge.
4. FUNCTIONING.
a. Time Action. Prior to projectile firing, the desired time is set on the movable time ring and the safety wire (figure 2) is removed. Upon munition firing, the time action plunger sets back, shearing its pins and moving rearward, forcing the primer striker against the primer. The primer initiates the powder time train. After the preset time has elapsed, the time train initiates the explosive train.
NOTE
The fuze will function superquick upon impact, as a backup, if the time setting exceeds the time of flight, the time setting is less than 0.4 second, or the time feature malfunctions.
Superquick Action. If the superquick option is selected, the movable time ring is set on S (safe) to interrupt the time train. Upon munition firing, the centrifugally operated interrupter (figure 2) moves outward, removing the block from the flash hole. Upon fuze impact, the firing pin is driven into the detonator, and the resultant flash travels down the flash hole to initiate the explosive train.
