C15A Wireless Signal Buzzer

[David Dunlop]

Mounted in the left rear corner of the Cab 13 WIRE-5 Truck, roughly by the ear of the co-driver, is a small wooden mounting bracket, with a signal buzzer fastened to it. This piece of equipment is very likely NOT unique to this particular CMP and was probably used in a number of vehicles where a crew in an isolated rear body needed to alert the driver and his mate in the cab of something important.

The back surface of the wooden bracket has been shaped to fit snugly in the corner curve of the cab and is held in place by two mounting screws set diagonally, upper left to lower right, when viewing the buzzer from inside the cab. The recessed lock nuts are identical to those used to anchor the roof of the 2K1 body immediately above and parallel to the side rain gutters. The screw is the same aluminum slotted truss head as well (although I have seen very thin headed steel hex screws also used -later replacements???).

In case someone needs to know what this particular item looks like, I have posted some pictures of one. For reference, the lens cap in the photos is 85mm diameter.

Sadly, there are absolutely no makers marks of any kind to be found on the buzzer, but I cannot help feeling that it was probably a very common devise pre-war: perhaps as a simple door buzzer in homes, or in street cars and other public transit vehicles. Certainly the lanyard/switch assembly slung along the ceiling of the 2K1 Wireless Body, used by either the wireless operator or Cypher Clerk to activate the buzzer was identical to those I remember seeing and using in Canadian Car and Foundry built Transit Buses in Winnipeg in the 1950's.

Anyway, for those that need, now you know what they look like, so it will hopefully be easier to spot one at your next antique shop or flea market visit.

David

[David Dunlop]

Last two pictures for your reference.


David

[Jordan Baker]

I was recently given this original buzzer for my C15a Wire-3 project. It came out of another Wire-3 truck.

The wooden block appears to match the other known original one posted above. There was still original SCC2 paint on the backside. However the buzzer on mine is a bit different. After some internet sleuthing I discovered this buzzer is still made today. It is the Edwards Dixie Buzzer #725. Once I had that, I found they are rather plentiful with everything from new made to period NOS ones available.

[David Dunlop]

Nice find, Jordan, and great to add to the pool of information on these buzzers.

It looks like your buzzer installation will have the wiring coming in from the top. On the 2K1 buzzer set up, the wiring comes across the cab/body gap below the floor in the left side corner of the cab and is fed up to the buzzer assembly, with one or two clips holding it in place. It's a two conductor shielded cable.

Any indications with your Wireless Body as to where/how the signalling wire was fed from the body to the cab?

David

[Jordan Baker]

Nothing was left on my truck. This came from a friends truck. He said you could see on the sheet metal where another was supposed to be punched beneath the wood block but hadn't been. From what I can remember on his truck I didn't see any remains of the wiring for this switch.

Did you have any remains of the wiring available for a picture?

Also, you made mention of a lanyard in the rear box used to activate the buzzer. Any pictures of this?

[David Dunlop]

Jordan. I think I have photos of the lanyard setup filed away somewhere, and possibly some of the conductor route through the 2K1 box and chassis/cab assemblies. May take a bit of searching.

The only thing I do not know for certain, is exactly where in the buzzer wiring the power feed fitted into the scheme of things. It is a single, two conductor shielded cable that exits the switch assembly connected to the lanyard and disappearing into the wall conduit of the 2K1 box. it is also a similar cable crossing from underneath the front of the box to under the left front corner of the cab and up the cab wall corner to the two bottom terminals of that particular model buzzer. Somewhere under the front of the 2K1 box, that signal buzzer line has to have a 'Y' in it to pick up the necessary power feed. My suspicion is that this feed feeds from the rear chassis wiring harness in some manner. Never seen the setup to actually understand it,

Which makes for an interesting side topic. Has anyone ever run across a Chevrolet 15-cwt rear chassis wiring harness with a connection fitting near the cab end of it that does not make sense, in that they cannot figure out what it supposed to tie into it? Maybe it could be for this signal buzzer setup and maybe it was used with the installation for your box as well, Jordan.


David

[Jordan Baker]

I found the following in the parts manual for the C15a.

[Jordan Baker]

Also found this listing for cable clamps. Any sign of these or mounting points on the cab floor?

[r.morrison]

David.....as soon as I saw the "guts" of the signal unit, I knew I'd seen that before. If I'm not mistaken, those units were used inexpensive "doorbells" when I was a kid. It was a standard within the household of post war housing here in Canada. Unless you had a little extra cash and could afford the elaborate "chime"s that decorated your living room and impress your neighbours. Robert

[David Dunlop]

Robert. I can remember those buzzers being used in Science classes at school in the 1950's, along with the big, tall, round 1.5V Telephone Dry Cell batteries made by Union Carbide and Northern Electric. Some of the batteries had brass posts with screw fasteners and others had the Fhanstock spring clip terminals.

David

[Grant Bowker]

A modern similar product from the original supplier, Edwards Signalling.
https://www.edwards-signals.com/file...talog_Page.pdf
It is rated for 6VDC operation as well as AC. (Sorry, no 12 V seen on their website - an argument against converting trucks to 12V?) Model 725 are on ebay as low as $9US.

On edit: it looks as if at least two different buzzers were used.

[David Dunlop]

Jordan. Neither of those cables show up in the August 1942 Chevrolet CMP Master Parts List. My Wire 5 was a June 13, 1944 build with the 2K1 Box.

Be great if we had production time frames for the various CMP bodies to cross reference with.

As for the clips, for certain there was at least one holding the cable on its way up the left corner of the cab. I think it was close to the midseam where the roof attached. Will see what the photos might have to say about that, when I find them.

David

[Jordan Baker]

That would make sense they are not in the 1942 edition since the FFW didnt come out until I believe 1943.

Here are a couple of pictures of the buzzer before it was removed. The wires would be coming up from the bottom. There is one cable clip bolted to the cab wall tight against the door frame. There was also another one further along the cab wall. Its not known if these are original though.

[Jordan Baker]

Picked up my buzzers yesterday. Here is a couple small short videos of them buzzing.

https://www.youtube.com/watch?v=BqhO...ature=youtu.be

https://www.youtube.com/watch?v=XvQz...ature=youtu.be

[Phil Waterman]

Hi Jordan

Loud little video, but you can see how it would get the drivers attention even in a CMP. Modern equivalent would get a recorded message saying the driver is unavailable at this time please leave a message.

As a teenager spent several summers working in a summer camp (1960s) because of the small number of people who could drive a nonsychro manual transmission I was selected to drive the camps 1948 F5 Ford stake truck hauling 18 to 20 campers. If they wanted the driver they pounder on the cab roof. Which was similar to being inside a kettle drum.

Enjoyin your work.

Cheers Phil

[David Dunlop]

Jordan. I found some photos of the Signal Buzzer Switch and Lanyard Setup for the 2K1/2K2 Wireless Boxes. This one is the switch itself. A simple teardrop shaped cover over the spring loaded contacts that are kept in the open position by the spring until the lanyard is pulled. The Lanyard is originally a white cotton heavy sash cord which ages into a weird reddish brown over time. it is looped through the switch plunger ring and clipped back against itself with a common metal cord/cable crimp.

I can guarantee these stitches were common items in the GM 100, 150, 200 and 250 Series Transit Busses they built well into the 1980's. The buses with the green tinted windows along the upper sides and that always smelled of diesel fuel inside. If you know of a transit bus graveyard anywhere nearby, definitely worth checking out.

David

[David Dunlop]

Jordan. Here is what the lanyard rings look like and the spacing arrangement along the 2K1/2K2 Wireless Box ceiling. Only two rings are used. The second, outermost ring is equally distant from the centre one as the centre one is from the switch. The lanyard is looped back upon itself at the end ring and crimped as per at the switch.

David

[David Dunlop]

Jordan. Here is what the run of wiring from the Signal Buzzer Switch to the wall conduit feed point should look like.

David

[David Dunlop]

Jordan. This is what the conduit pipe looks like in the front wall of the 2K1/2K2 Wireless Boxes. As you can see, it is actually placed inside one of the front wall steel frame channels. Welded at the base through the floor. The face of the upper elbow that pokes through the front plywood is threaded to take a finishing ring which holds the upper end of the conduit in place.

If you are wondering what the short cable is, sticking out of the front floor just to the right of the conduit, that is the ground cable which connects the end of the big copper buss bar to the steel frame of the box underneath the front floor. It is a heavy shielded copper cable for some reason.

A set of four flat grounding straps, with the flat end lugs on them, are located, two to each heavy steel U-Channel that house the oak rails. One at each end roughly where the big U-Bolts clamp the Wireless Body to the Vehicle Chassis Rails. This assures ground continuity for the electricals right back to the Cab and Chassis assembly.


Hope this all makes sense out there.

David