This design should work with nearly all doors and doorframes for motels, guest bedrooms and bathrooms and toilet stalls, where locks are missing or wish to be supplemented. The portable lock is made up of two folding steel plates like hinges bound together by a strong, thin, flexible strap. The strap extends from the middle of one plate, which presses against the outside door and frame surfaces, between the door and frame and through the middle of the second plate, which presses against the inside door and frame surfaces.

When the lock is mounted on the closed door, it looks like this from above:
outside <-->-- inside

When the strap is then tightened and locked in place from the inside, it looks like this:
outside I-I---- inside

The plates’ tight grip on both sides of the door and doorframe would make forced or surreptitious entry nearly impossible.
-- FarmerJohn, Apr 16 2004

I'd use it to lock people in.
-- skinflaps, Apr 16 2004


Is the strap visible from the outside, or is it fixed to the inside of the outer plate?

Also, I know you said it was a flexible strap, but I could still forsee problems, especially when tightening, if you are trying to lock a door with has a recess in the frame into which the door closes.
-- stupop, Apr 16 2004


Let me see if I understand this correctly: the plates go into the gap between door and frame, and the action of pulling the strap wedges the plates into the gap?

-- Ling, Apr 16 2004


[stupop] Yes, the strap should be fixed to the inside of the outer plate to deter damage. It might be tricky to make a strap thin, flexible and maybe slippery enough to glide through the angle(s) of a recess.

[Ling] No, no wedging. Pulling the strap straightens the plates. They don’t really need to be angled; I just thought it might make mounting easier.
-- FarmerJohn, Apr 16 2004


Let me see if I understand this correctly: the plates go into the gap between door and frame, and the action of pulling the strap wedges the plates into the gap?
-- Ling, Apr 16 2004


no, the plates go either side of the door and frame, the strap goes in the gap between the door and the frame, to keep the plates together
-- andrew1, Sep 27 2005


I wonder why my anno came up twice like that?
-- Ling, Sep 28 2005


If the plates are on the outside of the door, a simple hacksaw will probably let the burglar get in.
-- ye_river_xiv, Jun 28 2006


//If the plates are on the outside of the door, a simple hacksaw will probably let the burglar get in.//
I believe this is for toilet doors, where there isnt much risk of being burgled.
Except maybe by turd burglers....
-- andrew1, Jan 23 2008


Just remove the door to prevent uninvited guests from opening it.
-- MaxwellBuchanan, Jan 23 2008



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