A handle is the most useful feature on a manually handled container and the most troublesome on an automated one. It has to be somewhere a person’s hand goes naturally, which is usually exactly where a gripper closes, a label sits, or a scanner looks. Choosing the position deliberately, rather than accepting wherever the tooling puts it, is most of the work.
Where a hand actually goes
A person lifting a container from a shelf reaches over the top edge or under the rim. A person carrying it at their side grips the upper wall. A person pulling it off a stack grips the front top edge. Those are three different positions, and the most common is the upper wall on the two ends – which is unfortunately also the most common gripper position. Where both have to work, the handle has to be recessed or offset.
Recessed versus protruding
A protruding handle is easy to grip and it snags – on a conveyor guide, on a neighbouring container, on clothing, on wrap. A recessed handle does not snag and is harder to grip, particularly with gloves. Where containers run on conveyors at all, recessed is the only safe choice; where they are purely manual, protruding is more comfortable. Where they are both – the usual case – a recess with enough depth for a gloved hand is the compromise.
What a handle does to the wall
A handle is a hole or a recess in the wall, and the wall is what carries a stack. A handle near the top weakens the wall least, because that is where a rim or fold carries the load anyway. A handle in the middle of a wall removes material from the panel that a gripper squeezes, and that is the worst position for both strength and automation. High handles are better handles.
Handles and stacking
A handle that protrudes inward takes space from the contents; one that protrudes outward interferes with the container above in a stack or with the one beside it in a rack. Where containers stack, the handle has to be either recessed or positioned so the stack does not bear on it. Where they stack inside each other when empty, a protruding handle can prevent nesting entirely, which is a large cost for a small feature.
Two handles or four
Two handles, on opposite ends, cover most carrying and lifting. Four, one per side, allow a container to be handled from any position and are useful where two people carry a heavy load. Four also quadruples the interference problem. Where containers are heavy enough to need two people, four handles are right despite the cost; otherwise two is the better answer.
What automation needs instead
Where a container is handled automatically, the machine needs a feature it can engage, and that is frequently not a handle at all – it is a rim, a lip or a flat face. Where both are required, the handle should be on the faces the machine does not use, and that should be established from the machine’s approach direction rather than guessed. See what a gripper needs from a box wall, where the same faces are discussed from the machine’s side.
Testing a handle
Have the people who will use it lift the loaded container twenty times, and note whether they use the handle at all. Where they grip the rim instead, the handle is in the wrong place and it is not being used. That is a ten-minute test and it is the only reliable way to know – handles are frequently specified in positions nobody actually grips.