stoppers

A stopper is a device or component designed to prevent, limit, or seal movement or access within a system. Stoppers are used across many industries, and their form, material, and function vary accordingly. They can serve as physical barriers that halt motion, as closures that seal vessels, or as cushions to protect components during contact.

In mechanical engineering and machinery, stoppers often take the form of end stops or travel stops. These parts block a moving component at a defined position to prevent over-travel, misalignment, or collisions. They may be fixed or adjustable and are commonly made from metal, hard plastics, or composites, sometimes with a cushioning interface to reduce impact.

In laboratory, pharmaceutical, and industrial processing contexts, stoppers are closures that seal openings in bottles, flasks, test tubes, or pipes. Materials include rubber, cork, silicone, neoprene, or other elastomers chosen for chemical resistance and temperature tolerance. These stoppers must fit the vessel dimensions and resist deforming under pressure or exposure to solvents.

In packaging and consumer goods, bottle stoppers or closures seal liquids and powders to preserve contents and prevent leakage. Corks, synthetic stoppers, and threaded caps with gaskets are typical examples, selected for compatibility with the container and contents.

In doors and furniture fittings, door stoppers prevent doors from striking walls or frames, while small wedge or rubber stoppers protect surfaces and reduce noise.

Design considerations for stoppers include size, fit, material compatibility with the environment, resistance to wear, chemical exposure, and the specific loading or sealing requirements of the application.