The Spring Lock - 1912 was released on:
USA: 7 September 1912
To take the lock plate off requires a lock plate spring compressor. With the spring compressor in place and the spring slightly compressed remove the circlip that holds the lock plate on. Then release the spring compressor and the lock plate simply slides off.
Without a spring, the lock would never unlock. Therefore, a lock of a door required a spring.
Use a spring compressor to push the lock plate down slightly, then remove the circlip that keeps the plate on. Release the spring compressor and the lock plate will come off. Reverse the procedure to reinstall.
A valve spring "keeper" or AKA a valve spring "retainer" is used to lock a valve spring to the valve.
The Door That Has No Lock - 1921 was released on: USA: 26 June 1921
The Girl at the Lock - 1914 was released on: USA: 7 October 1914
Time Lock No- 776 - 1915 was released on: USA: January 1915
Lock Her Room - 2003 was released on: USA: 4 February 2003 (TV premiere)
The Time-Lock Safe - 1910 was released on: USA: 17 March 1910
Lock Box - 2015 was released on: USA: 1 January 2015 (DVD premiere)
Lock the Door - 2010 was released on: USA: 1 November 2010 (Los Angeles, California)
Lock Your Doors - 2006 was released on: USA: 24 April 2006 (Tuscaloosa Film Showcase)