This apparently is a Tayhope (brand name) lock. I found information about it at the company's website:
In commercial ventures, where access points need to be locked, padlocks are often used as they offer high security with low maintenance. Most companies nowadays use cloned padlocks operated by one corporate key, this allows easy access to many sites where the company has an interest. Multiple-Locks allow companies to share access points without having to share keys. An installed Multiple-Lock may have up to 10 users each opening and closing the access point using their own padlock.A video at the company website illustrates some of the mechanics. Note that gaining access does NOT require the simultaneous presence of 10 users with ten different keys - unlocking any ONE of the ten padlocks allows the gate to be opened.
Image cropped from the original at Nothing to do with Arbroath.
Addendum: Readers offer some other varieties for multiple-user access in the Comments below.