Southco locker lock looks like it can never work!?

[Mike633]

Folks,

I'm confused by a Southco cam lock that closes the gas bottle compartment on a caravan I just bought. There are two locks for a 5ft fibreglass door. It's a cylinder key marked 715 which seems to be a standard. The locks are marked Southco too but no part number. The key fits the lock but doesn't turn the cam as it has nothing to grip on to. There are grooves in the key but none on the lock. It's not that they have worn off: they were never there: there are no scratches in the oxidation layer. I thought perhaps the trick was to push down the outer cylinder thus exposing the keyway but the outer facing metal is a smooth 'top hat' of die cast alu or zinc.

There is some complex locking mechanism inside and it's not broken as both operate the same. The top hat moves inwards about 2mm under pressure and the rear threaded shaft is also sprung loaded outwards. The shaft turns through 90 degrees with the top hat when out but when pushed into the lock (moves about 6mm) turning is resisted (ie: 'locked'). Push in and turn fractionally and it pops out 3mm but is still locked. Push the top hat in from the front and release, and so does the shaft which will now turn again.

It's marked Pat pend. and I had a look at some Southco patents but there are too many and I didn't find the one for this lock.

It's possible that the 715 key, although fitting, doesn't match the locks. But I can't see how the lock was ever supposed to work as no keyway is visible.

The lock is assembled from the outside and there's one 1x4mm rectangular push pin from one side holding it together. So no easy disassembly. I took pics but as a newbie I can't post.

Can anyone tell me how a lock with no keyway works??

Thanks.

[Squelchtone]

go to photobucket.com and create an account, then use [URL] pr [IMG] links here to show the pics, because honestly, a pic is worth a 1000 words and we'd like to help you, but just a note of caution, automotive locks, even if they are not doorlocks or ignition locks are off limits and not discussed in the public forum because of the danger that someone can come along find this site and start learning how to get into cars, we would not want that.

here's an example of how to post a pic.

[img]theURLpathtoyourphotobucketalbum[/img] <-- this would show an inline pic on the forum

[url]theURLpathtoyourphotobucketalbum[/url] <-- this would show a hyperlink to the photobucket site for users here to click on and see the pic there.

try it out, it will take you five minutes to upload some pics to there and link them here. Just remember the whole car rule, this could easily turn into advanced area discussion and we may have to lock the thread or move it into the automotive sub forum. I hope that's fair enough.

Also, if may I throw this out.. would a web forum to Caravan owners and mechanics perhaps have more information than here? You may consider finding one to see if people there already have the answer you seek.

Thanks and welcome to the forum.
Squelchtone

[Mike633]

Thanks ST.




I don't think there's any auto security issue at stake. The locks are only secure when the cam arm is under compression, and in this application they are under tension due to the rubber door seal. I opened them by stuffing the key with blu-tak to get some friction as instucted by the previous owner. I posted here because I have two engineering degrees and without attacking the begger with a drill I can't figure out how it was even supposed to work. It's an intellectual challenge to return them to actual locks as Southco intended.
Cheers.

[Squelchtone]

Thanks ST.


I don't think there's any auto security issue at stake. The locks are only secure when the cam arm is under compression, and in this application they are under tension due to the rubber door seal. I opened them by stuffing the key with blu-tak to get some friction as instucted by the previous owner. I posted here because I have two engineering degrees and without attacking the begger with a drill I can't figure out how it was even supposed to work. It's an intellectual challenge to return them to actual locks as Southco intended.
Cheers.

That's an interesting little top hat/boss inside the lock.. I see no pins like you would expect to see, and have to say "wtf!?" lol I'm sure someone will see this tonight and know exactly whats up with it. very interesting though, thanks for sharing so far, glad to see it is not mounted to a vehicle

interesting indeed,
Squelchtone

[Squelchtone]

one note.. on in exterior diameter of that boss or top hat is there anything protruding that would allow a key to index with it? This could just be a faux-lock where any tubular key from southco would turn it and so there are no pins because it doesnt use pins, it just needs something to index with the top hat and turn.

just a thought.

Squelchtone

[straightpick]

That particular type lock is called a vise action compression lock. They are used on tool boxes/doors on railroad equipment, trucks, etc. to keep the doors from opening due to vibration. They work exactly as you indicated - the rubber gasketing is compressed by pushing the door closed and throwing the latch and are operated by a "tool" that matches the lock. In your case it appears that at one time it had raised portions on the inner part of the lock where you insert the key that match the key. Yours appears to have worn off from usage. Time for a new one!

[Mike633]

I was going to disagree, but a bit of work with a drill and you are right
What confused me was the Southco brochure I looked at was smaller vice latches so the dimensions were wrong, plus the locking mechanism I could engage which I did not think was needed for the 'faux' latch, plus the relatively unmarked top hat on both latches, plus the spring bias outward when I thought a latch would be inward

So for the record, I find larger latches here
http://www.southco.com/list/e3-vise-act ... 76.000;783
The top hat sides are oxidised so look unworn. Clearly the newly exposed metal is shiny where I have cut a screwdriver slot:

I can only imagine that the teeth were worn off many years ago.
On the locking mechanism, this is open:

The first quarter turn acts like a passive latch:

During the second quarter turn of the key, the lever stays at the same angle but is pulled into the lock body by 6mm. Compare the unthreaded section of shaft:

In this position it is 'locked' in that the lever cannot be turned, it has to be released by the key.

So thanks lockpickers!

[Rickthepick]

i have a load of master keys for the southco locks, just never had a lock to try them on

[raimundo]

have you tried pressing the key hard into the lock to see if the apparent bottom of the keyhole will move further in? possibly exposing something to grip with that key which may be more of a wrench head for a hidden part that it grips.
there are such locks, I have one which is round and the bottom of the keyway is pushed in to make it work. its on somekind of phone that was probably a privately owned pay phone. Someone who works in scrap metal and gives me interesting locks gave that phone to me, Im on the point of throwing it out but will try to remove the lock first. its rinky dink black plastic thing that is taking up space.

[Mike633]

It's a fine theory. In fact when I couldn't see a keyway that's how I thought it would work: a tube around a cylinder, with the tube pushing back to reveal the keyway. Unfortunately some prodding showed the top hat to be all solid metal. It does push in a couple of mm but it makes no difference to the lock.

[stratmando]

Years ago on some Cable Boxes, they had a security screw that "Appeared" Round, but was slightly out of round, I found something round and slighty crushed it to make it slightly out of round, Worked very well for removing the screws. Wonder if this is simular.
And you say it moves freely, back forth and in with no key? What all turns in keyhole when moving latch, the center only?

[stratmando]

I got their catalog the other day, lot of nice hardware.
went to southco.com and found this:
http://www.southco.com/class/e3-vise-ac ... tml?ctid=1