A key retainer device (KRD) is a small metal unit that is wall or door mounted, usually designed for the interchangeable core that retains one key (Key A) while the second key (Key B) is used for authorized purposes. When the key in use (Key B) is returned into the key retainer, the key held captive (Key A) is turned and then can be released. Now, the special key, perhaps top master (Key B) is held captive again. The key retainer is an excellent method for providing visual key control.
These include Janitorial/Custodial, Irregular Users, Guests and other authorized users that require access. The KRD acts as a "mechanical sign-out sheet" for desk and cabinet keys, carpools, evidence and gun lockers, hospital narcotics carts and storage cabinets. It is an excellent "tool" in a company's key control arsenal - a simple solution to complicated problems that is often ignored. The KRD provides an easy way to establish accountability and eliminate human mistakes by physically controlling the desired locking sequence or procedure(s) and it drastically reduces the risk exposure to higher level keys (Grand Master, Master and Controls) by requiring them to remain on-site. The actual keys are "buried" in the core for additional security. The cores are spaced and oriented to allow for large bow keys and key rings with I.D. tags attached.
One key (High Level/Special) is retained in a core (at 1/4 turn) until another "release" key is inserted in the other core and rotated 90° (1/4 turn). Then the "retained" key can be removed for use while the "release" key is held (trapped) for visual accountability purposes. This cycle is repeated in reverse when the normally "retained" key is returned and the "release" key is removed "retrieved" by the authorized user. A very simple "put and take" system.
Key retainers are manufactured to accept cores/keys from a wide variety of manufacturers and formats. Small format interchangeable core models are compatible with keying systems manufactured by: BEST, Arrow, Falcon, Schlage, InstaKey, KSP, Lori, Kaba-Ilco, Ultra Security, Medeco KeyMark, Yale KeyMark, Scorpion, MBS, KSP, Marks and GMS. Large format interchangeable core models accept cores/keys from: Yale, CorbinRusswin, Medeco, Schlage, Sargent and ASSA. ICLS is the leader in sales for all types of key retainer devices.
The term "key retainer" can also refer to a padlock that does not allow the key to be removed when the shackle is in the open position. This prevents accidentally leaving the padlock unlocked, and it also prevents accidentally locking the key inside a locker, shed, etc.
"Small Format Interchangeable Cores: Advanced" ©2005 by William M. Lynk; Published by The National Publishing Company, Chicago, Illinois; pp. 212-214. Possible conflict of interest/self promotion.