Tip: Non-structural latch

vmirv8bldr · #1 08-26-2008, 01:19 PM

I like the idea of the rear-battery access door on the RV-8 and saw several versions of them. I chose to do the same thing with my RV-8, but wanted a simpler, push-to-close latch. My employer makes hardware with a push-to-close latch I like, so I "liberated" a couple to experiment with.

The latch has a self-contained spring mechanism, so all that is required is a 1.0" x 1.5" rectangular hole and a doubler. The doubler is just to bring the material thickess up enough to engage the spring.

I finished the battery access door last night and am very pleased with how well this latch works. A tug on the latch opens the door, and a gentle motion closes it. I'll post a pic of my actual installation tonight.

One could use the latch to hold virtually any hinged panel closed. It is not quite flush, but weighs next to nothing and may be cheaper than Hartwells or Camlocs. (Mine was definitely cheaper!!)

Here's a link to the latch information. Go to page 4 of the PDF for the actual Southco Latch I used (Series 40, 1.6mm, PN A3-40-525-12)
http://www.southco.com/resources/documents/a3.en.pdf

JDanno · #2 08-27-2008, 09:05 AM

Bart are there any "five finger discounts"??

Just joking, of course. Thanks for the info.

vmirv8bldr · #3 08-27-2008, 09:31 AM

I did a quick google search for these last night, just to see where one would get them and how much. I found a Canadian place, and the price was less than $5.

I MAY be able to get my hands on a few more. If a handful of folks want them, I can check the scrap bin occasionally (where I liberated mine) and you can just pay shipping.

PM me.

In order to ensure our tradeshow products look presentable, doors are frequently scrapped and replaced when they are damaged in transportation. I got mine off the scrapped, damaged doors.

The one I used, and can get, is the one in the top center on this page:
http://www.southco.com/product/class.aspx?cid=7392

(Moderators please relocate if necessary / appropriate)

N62XS · #4 08-27-2008, 12:06 PM

This is the latch that was included with my CF baggage door. It is a reliable, easy to install piece of hardware.

AussieRV · #5 08-27-2008, 08:16 PM

Hey Bart,

Any pics of your battery hatch & latch ... wouldn't mind seeing your version of construction ... gives me ideas

Cheers,

Matt

vmirv8bldr · #6 08-27-2008, 10:08 PM

Yeah, meant to do this yesterday but I riveted the aft top skin instead.

Here's the battery access door I made using the above mentioned latch. Notice I added a small piece of material to get the grip depth correct for the latch. Also, I am mounting my ELT on this shelf, so I liberally added angle stock and a doubler (under ELT) to make it more stable. I think the ELT mounting instructions said no more than a 0.1" deflection with 130lbs. I haven't tested that much weight on here, but I used 1"x1"x1/8" stock, should be plenty strong:

Here's a close-up of how the push-to-close feature works. The ramp on the "grabber" part pushes the latch in and then the spring pushes it closed as it engages the other side. (This would be really hard to understand without a picture.)

Here's a picture of me holding the door open, maybe it's easier to see how it works here:

Like I said, I am very pleased with how this latch works. Gently pushing the door rearward (closed) and letting it fall on it's own is enough to engage the latch, and a simple pull is enough to open the latch and door at the same time.

Hope it's clear as mud now. Didn't mean to hijack my own thread and make it a battery access door thread, but that's what I used the latch for.

RVadmirer · #7 08-27-2008, 10:27 PM

Is there a particular reason you preferred this over an aircraft latch?

vmirv8bldr · #8 08-28-2008, 07:41 AM

Lighter, simpler, and most importantly, FREE.

Such is the beauty of experimental aircraft.

I considered a Hartwell or Camloc (this came in a close second, due to price and availability), but for this application, the door normally wants to stay closed due to gravity anyway, so the latch just keeps it that way. Also It's an inside application with no significant pressure on either side of the door, so no clamping force is required of the latch. It's nearly flush and I can easily open and close the door with one finger.