Wooden Box

Crates:

Huge wooden boxes used to ship very large or heavy objects are known as crates. Wooden crates have self supporting structures. A box is termed as a crate only after all six of its sides are put in place and rated in combination to determine the strength of the crate. The ratings are different from ordinary boxes in that, the strength of other wooden boxes are rated on the basis of their weight before the tops and ends of the crate are installed. The first documented evidence of shipping crates can be found in US in a handbook written in 1930. The handbook was written by C.A Plaskett for the US Department of Agriculture. Even though the handbook states that crates were defined well before that time.
The handbook writer, C.A. Plaskett was well known for extensive testing and defining of various packing components. Even though a definition of the wooden crate has been put forward, construction of a crate is always not so simple. Very often the construction can result in a container that is neither a box nor a crate. Wooden crate designs are varied. The three most common types of crates are closed crates, open crates and framed crates. Closed crates are those which are completely or nearly completely enclosed with plywood or lumber boards. In case of using lumber, the constructors leave gaps between the boards to allow for expansion. Open crates are those that use lumber for sheathing. The sheathing is gapped at various distances. Open crates and closed crates cannot be characterized by definitions. Usually when the gap between the boards are more than what is required for expansion, the crate is considered an open crate. Ideally the gap between the boards should not be more than the width of the sheathing boards. When the gap between the boards is larger, the boards are considered cleats rather than sheaths. This renders the crate unsheathed. The unsheathed crates are known as frame crates. A frame crate contains a skeletal structure and no other material is added for surface or pilferage protection. An open crate is typically made out of twelve pieces of lumber. Each of the lumber pieces are placed along the outer edge of the content and more lumber is placed diagonally to avoid distortion from torque.

Pottery Bowls:

More boards in the crate are added after the crate reaches a specified size. These boards are known as cleats. Cleats are used to support the panels that reach a certain size requiring added support. Cleats are placed anywhere between the edges of a given panel. Cleat placement on crates is determined by the width of the plywood used on plywood sheathed crates. On other crates the cleats are used to strengthen the panel and spaced evenly. At times two cleats are added across the top panel of a crate placed in order to give the top of the crate added strength. This is done in case of crates where lifting chains or straps may be placed on top of the crate while lifting. Cleats have specific names depending on the benefits that they provide. Lumber placed under the top of a wooden crate to add support for a large top is called a joist. Lumber built into the mid section of the top of a wooden container to strengthen the top is called a cleat. While designing a crate, the transportation methods and storage conditions should always be considered. Every step of the transportation process will result in different amounts of stress from shock and vibration.