# What is the device on these doors? **URL:** \ **Category:** Factual Questions\ **Created:** [June 17, 2010, 10:32pm UTC](https://boards.straightdope.com/t/what-is-the-device-on-these-doors/543606 "2010-06-17T22:32:40Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![hlanelee](https://avatars.discourse-cdn.com/v4/letter/h/3bc359/32.png) [@hlanelee](https://boards.straightdope.com/u/hlanelee)\ **Post date:** [June 17, 2010, 10:32pm UTC](https://boards.straightdope.com/t/what-is-the-device-on-these-doors/543606/1 "2010-06-17T22:32:40Z")
One summer we spent a week at a beach house on Sullivan’s Island, SC. In the photo, you see a device attached to a door. [http://hlanelee.angelfire.com/thing.jpg](http://hlanelee.angelfire.com/thing.jpg) There were several of them attached to doors throughout the house. It’s a hollow steel ball attached to an arm, which was attached to the door. It could move back and forth like a pendulum, but it rubs against the door and doesn’t move freely. You can see the rub marks on the door. So it didn’t swing by simply opening or closing the door. This photo was taken in 2003 and I still don’t know what it is or what purpose it served. If you know what it is, please let me know. ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [June 17, 2010, 10:36pm UTC](https://boards.straightdope.com/t/what-is-the-device-on-these-doors/543606/2 "2010-06-17T22:36:20Z")
I just get a blank page when I click on your link. ---
**Author:** ![Patty\_O\_Furniture](https://avatars.discourse-cdn.com/v4/letter/p/96bed5/32.png) [@Patty\_O\_Furniture](https://boards.straightdope.com/u/Patty_O_Furniture)\ **Post date:** [June 17, 2010, 10:37pm UTC](https://boards.straightdope.com/t/what-is-the-device-on-these-doors/543606/3 "2010-06-17T22:37:21Z")
Looks like agelfire doesn’t like hotlinking but what you describe sounds like a door knocker. ---
**Author:** ![jjimm](https://avatars.discourse-cdn.com/v4/letter/j/ba8739/32.png) [@jjimm](https://boards.straightdope.com/u/jjimm)\ **Post date:** [June 17, 2010, 10:37pm UTC](https://boards.straightdope.com/t/what-is-the-device-on-these-doors/543606/4 "2010-06-17T22:37:45Z")
Angelfire doesn’t allow hotlinking. Even from [www.angelfire.com](http://www.angelfire.com) as I tried. Can you post it somewhere else? ---
**Author:** ![mnemosyne](https://avatars.discourse-cdn.com/v4/letter/m/c4cdca/32.png) [@mnemosyne](https://boards.straightdope.com/u/mnemosyne)\ **Post date:** [June 17, 2010, 10:39pm UTC](https://boards.straightdope.com/t/what-is-the-device-on-these-doors/543606/5 "2010-06-17T22:39:59Z")
You can copy and paste the link directly into your browser address bar and get the image. I have no idea what it is. ---
**Author:** ![Darryl\_Lict](https://avatars.discourse-cdn.com/v4/letter/d/7cd45c/32.png) [@Darryl\_Lict](https://boards.straightdope.com/u/Darryl_Lict)\ **Post date:** [June 17, 2010, 10:51pm UTC](https://boards.straightdope.com/t/what-is-the-device-on-these-doors/543606/6 "2010-06-17T22:51:05Z")
Door stop, maybe? ---
**Author:** ![Gary\_Robson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gary_robson/32/3448_2.png) [@Gary\_Robson](https://boards.straightdope.com/u/Gary_Robson)\ **Post date:** [June 17, 2010, 10:58pm UTC](https://boards.straightdope.com/t/what-is-the-device-on-these-doors/543606/7 "2010-06-17T22:58:22Z")
[moderating] I’ve changed the title of this thread from “What is this?” to “What is the device on these doors?” As a charter member, **hlanelee** , you should be aware by now that we require descriptive thread titles. [/moderating] ---
**Author:** ![Patty\_O\_Furniture](https://avatars.discourse-cdn.com/v4/letter/p/96bed5/32.png) [@Patty\_O\_Furniture](https://boards.straightdope.com/u/Patty_O_Furniture)\ **Post date:** [June 17, 2010, 11:12pm UTC](https://boards.straightdope.com/t/what-is-the-device-on-these-doors/543606/8 "2010-06-17T23:12:33Z")
Very hard to get a sense of perspective from that picture. Is this a pocket door? If so, it could be the door pull. Does it ring if moved? Maybe it’s an alerting rig to let people know that somebody has opened the door? ---
**Author:** ![hlanelee](https://avatars.discourse-cdn.com/v4/letter/h/3bc359/32.png) [@hlanelee](https://boards.straightdope.com/u/hlanelee)\ **Post date:** [June 17, 2010, 11:13pm UTC](https://boards.straightdope.com/t/what-is-the-device-on-these-doors/543606/9 "2010-06-17T23:13:58Z")
[quote=“Gary “Wombat” Robson, post:7, topic:543606”] [moderating] I’ve changed the title of this thread from “What is this?” to “What is the device on these doors?” As a charter member, **hlanelee** , you should be aware by now that we require descriptive thread titles. [/moderating] [/QUOTE] Sorry, but I have been away for quite a while and didn’t think. Please don’t shun me. ---
**Author:** ![hlanelee](https://avatars.discourse-cdn.com/v4/letter/h/3bc359/32.png) [@hlanelee](https://boards.straightdope.com/u/hlanelee)\ **Post date:** [June 17, 2010, 11:19pm UTC](https://boards.straightdope.com/t/what-is-the-device-on-these-doors/543606/10 "2010-06-17T23:19:12Z")
> [@Patty\_O\_Furniture](#): > > Very hard to get a sense of perspective from that picture. Is this a pocket door? If so, it could be the door pull. Does it ring if moved? Maybe it’s an alerting rig to let people know that somebody has opened the door? They were on regular room doors. They did not ring. They just swung back and forth on the plane surface of the door. ---
**Author:** ![jnglmassiv](https://avatars.discourse-cdn.com/v4/letter/j/f07891/32.png) [@jnglmassiv](https://boards.straightdope.com/u/jnglmassiv)\ **Post date:** [June 18, 2010, 12:46am UTC](https://boards.straightdope.com/t/what-is-the-device-on-these-doors/543606/11 "2010-06-18T00:46:15Z")
Were the others near the edge of the doors like the one in the photo? If so, I’m with **Darryl Lict**. Maybe you turn it 90 degrees to prevent a door from swinging shut. Further WAG: Something to do with hurricanes? ---
**Author:** ![SantaMan](https://avatars.discourse-cdn.com/v4/letter/s/da6949/32.png) [@SantaMan](https://boards.straightdope.com/u/SantaMan)\ **Post date:** [June 18, 2010, 1:09am UTC](https://boards.straightdope.com/t/what-is-the-device-on-these-doors/543606/12 "2010-06-18T01:09:18Z")
Good grief, I haven’t seen one of those since I was a kid. Looks like the device we had on the screen door. If the door was closing too fast, it would swing out and cushion the door from the slam. The door would bounce back slightly, close more slowly and the ball would not swing out. ---
**Author:** ![Gary\_Robson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gary_robson/32/3448_2.png) [@Gary\_Robson](https://boards.straightdope.com/u/Gary_Robson)\ **Post date:** [June 18, 2010, 10:56pm UTC](https://boards.straightdope.com/t/what-is-the-device-on-these-doors/543606/13 "2010-06-18T22:56:07Z")
> [@hlanelee](#): > > Sorry, but I have been away for quite a while and didn’t think. Please don’t shun me. No problem! Welcome back.