Is one 420 N handle enough for a 28.4 kg Field Mission Equipment Case?

Answer: Yes, with about 1.5 times margin over the 279 N lift, if both handles stay serviceable.

Will five tiers of pallet stacking crush the lid?

Answer: Not crush, creep. The bottom lid carries about 113.6 kg, and a 3.5 mm lid at 65 °C sags 3 mm in three months and the gasket will not seal.

Why four harness points instead of two?

Answer: Two would take 139 N each and turn off-axis pull into shear at the insert; four cut it to 69.8 N and hold two directions.

Is the 110° lid angle adjustable?

Answer: No. It leaves 200 mm between rim and mouth for a gloved hand; at 95° the gap falls to 120 mm, at 120° the strap load doubles.

Can the 12 kPa valve let water in?

Answer: Not the valve, but its position can. On top it is pinned by the case above and the disc cannot reseat.

Field Mission Equipment Case

Quick answer: A Field Mission Equipment Case meets three loads a trip: 5-tier stacking, 28.4 kg carried, a 110° lid, held by 420 N handles and 3.5 mm walls.

Three Transfer Legs, Three Sets of Numbers
Vehicle Leg: Pallet Stacking and Strap Pinch Points
Carrying Leg: Four Harness Points and the Mass Line
Camp Leg: The 110° Lid Angle and One-Hand Access
How Valve, Latches and Drop Margin Split Up
FAQ

1. Three Transfer Legs, Three Sets of Numbers

The same shell meets three load paths that share nothing: stacking plus a strap on the vehicle, four-point hanging plus sway on the march, hinge torque plus an off-centre lid at camp. The 620×420×280 mm outside and the 560×360×230 mm cavity come from the overlap of all three; another 20 mm of width and a 1200×1000 mm pallet no longer takes 12 cases.

Leg	Load point	Design value
Pallet stacking	Lid corners and rim	5 tiers, 4 cases on the bottom lid
Carried	4 harness points	180 N each, 720 N total
Hand-carried	2 handles	420 N each, 279 N static

Empty 6.4 kg and payload 22 kg stay separate: the first sets the inertia of a lift and the overturning moment of the lid, the second the static load on handles and harness points, and their sum is the 28.4 kg this Field Mission Equipment Case is judged at.

2. Vehicle Leg: Pallet Stacking and Strap Pinch Points

A Field Mission Equipment Case passes its pallet load through four corners, never the middle of the lid. A 620×420 mm footprint on a 1200×1000 mm pallet carries 12 cases and 340.8 kg, and once the webbing is tensioned the force gathers on two 30 mm bands, the rim and the latch seats. The lid centre stays unmarked.

Field Mission Equipment Case stack of four black cases on steel shelving, left one open with radios and a tablet in foam cut-outs

Where the strap crosses is decided by the latches. Two 380 N latches sit close enough to the rim that a strap over them loads the seat in tension and shear at once, and the closing face shifts 0.5 mm. One side of the gasket is then crushed and the other hangs free, and IP67 at 1 m for 30 min survives only on paper; webbing between the latches keeps the lid in compression.

Five tiers of static stacking on a Field Mission Equipment Case is another problem. The bottom lid carries about 113.6 kg for months, so creep matters more than strength: a 3.5 mm lid at 65 °C sags past 3 mm and the gasket stops sealing.

3. Carrying Leg: Four Harness Points and the Mass Line

On the carry the harness points govern, not the handles. Four points at 180 N give 720 N against 28.4 kg, 69.8 N each, a margin of 2.6. The insert fails by pull-out rather than fracture: set into a 3.5 mm wall, it meets shear once the load swings 45° off vertical.

Where the mass sits decides the walk. The cavity is 230 mm deep. With 22 kg aboard, the centre of gravity lands about 20 mm below the geometric centre. A four-point line above it makes a Field Mission Equipment Case rock; below it the case rides on the hip. Set the points 40 mm to 60 mm below that centre. The offset is not comfort; it is the boundary of the sway period.

Load point	Condition	Design value	Margin
Handle root	One-hand lift of the full case	420 N each	1.5×
Harness point	Loaded walking over rough ground	180 N each	2.6×
Latch face	Side compression in a stack	380 N each	1.4×

4. Camp Leg: The 110° Lid Angle and One-Hand Access

At camp a Field Mission Equipment Case is judged by a 110° lid angle. At 110° the lid centre of gravity passes about 25 mm beyond the hinge axis, so the limit strap, not the hinge, holds it: ten degrees more doubles the strap load, ten less and a gloved hand no longer fits.

Field Mission Equipment Case olive rotomolded shell open on a stainless bench, egg-crate lid foam, paper-wrapped packs, steel corner plate and pressure valve

One-hand access needs 230 mm of clear space at the mouth, exactly the cavity depth. At 110° the rim clears it by 200 mm; at 95° that falls to 120 mm and a thick glove will not pass. Strap length fixes the figure, not the hinge.

5. How Valve, Latches and Drop Margin Split Up

A 1.2 m drop on six faces is the overall check. An edge-first landing produces the highest acceleration, and the latches take a lateral component as well as tension. The 380 N on each latch is static; a drop multiplies it three to five times, so the plastic at the latch seat is thickened outside the 3.5 mm skin.

Design value	What sets it	What happens past it
3.5 mm wall	No set after a 1.2 m drop	Edge dents beyond 2 mm
420 N handle	One-hand lift against 279 N static	Whitening cracks at the root
110° lid angle	230 mm clearance for one hand	Strap out, hinge boss cracks
12 kPa valve	Pressure differential over 90 K	Disc fails to reseat, water in
5-tier stacking	Three months static	Lid sags past 3 mm

On a Field Mission Equipment Case the valve opens at 12 kPa because −25 °C to 65 °C spans 90 K. A cold night into a sunlit vehicle body builds more than 8 kPa across the wall, the disc lifts, and closing the lid seats it again on its own spring. A disc that does not reseat turns IP67 at 1 m for 30 min into a laboratory figure, so the valve sits on the lid side, never on top.

Conclusion

The legs of a Field Mission Equipment Case cannot borrow margin from each other: the vehicle leg needs lid corners a strap will not flatten, the carry leg needs four inserts that will not pull out, the camp leg needs 230 mm of clearance at 110°. On a Field Mission Equipment Case the 3.5 mm wall, the 420 N handle and the 380 N latch each answer one leg, and scaling any across the shell pushes the loaded case past 30 kg.