padlock

A padlock is a portable mechanical lock consisting of a metal body, a shackle that fits around a hasp or chain, and an internal locking mechanism. The shackle is released when the correct key, combination, or other unlocking method is applied, allowing the shackle to be withdrawn. Padlocks are designed for temporary or travel security and are used on gates, doors, lockers, suitcases, and other items that require portable protection.

Most padlocks come in keyed and combination varieties. Keyed padlocks use a cylinder that aligns internal pins, wafers, or levers to permit rotation and opening when the correct key is inserted. Combination padlocks dispense with a key and rely on dialing or inputting a sequence of numbers or patterns to align internal discs or wheels and release the locking mechanism. Modern designs may employ disc-detainer systems or electronic components for smart padlocks that respond to Bluetooth, key cards, or biometric input.

Construction materials vary but commonly include hardened steel, brass, and weather-resistant coatings to resist corrosion and tampering. Some padlocks feature shrouded or laminated shackles to deter cutting, while others offer double-locking mechanisms that engage the shackle in multiple positions for added security. Weatherproof or heavy-duty models are used in outdoor or industrial settings.

History and use: padlocks have ancient roots, with early warded and lever designs, but portable padlocks in various forms were developed and manufactured extensively in Europe during the 18th and 19th centuries. Today they are ubiquitous for everyday security needs, though they are not immune to bypass methods such as cutting, drilling, or lock-picking, and higher-security models are chosen when greater protection is required. See also Lock and Key concepts.