Sprint quick changes: how do they go in/out of drive?

When sprint car drivers roll to a stop, they pull the quick change out of gear, but I can't figure out the internal mechanism. I see they have a lever and cable, but what/how does it operate on?
I'm guessing there is a spring 'detent' of some sort that helps the cog slip back in when they rock the car to get it in gear. Is there a website or photo or schematic that would make this clear to me?

 

They use an "in-out" box.

http://www.indianaopenwheel.com/showthread.php?t=54808

 

I believe speedway has a diagram in their catalog.

 

Modern Sprint Cars haven't used in/out boxes since the 60's.
There is a coupler on the back end of the crank with a u-joint and a shaft back to the Q/C.
Another sliding coupler in the Q/c is what the cable you see controls.

 

The links etc still don't show my "non-engineering" mind what the slide-coupler and the lever + cable mechanism looks like or how it works --- anyone have a photo or diagram?

 

The old cars used an in-out box, anything from 75ish (approx) on used a slider rear. The lower shaft in the rear slid in and out of gear. Still the same today.

 

Granted, many cars used the in out boxes into the 80's.

 

As said already, old cars used "In & Out" box at back of engine. Just a hand shifted coupler. The newer cars shift the rear axle. In simple terms, it slides one of the quick change gears.

 

Thanks; so the lower shaft is pulled forward by the cable and lever, presumably when the driver is off the gas. Is there a spring tghat helps nudge it back again when they want to restart?

 

There is a splined coupler on the lower shaft that is engaged by the lever and locks the the lower spur gear to the lower (drive) shaft. It's not real clear, but if you study this schematic a little it will become more apparent:

 

They have a 2 piece or split jack shaft. Pull the lever to disengage, it slide a collar off the spline separating the shaft into 2 separate shafts, NO going anywhere. Move the handle to engage, the collar slides down on the spline and locks the 2 shaft as one, allowing the transfer of torque to the R+P.

 

I've got a old show car engineering quick change cover in which you move the lower gear in and out in the rear cover.......another idea...Lol

 

Most modern sprinters use a slider coupling between the engine and diff, the "rocking" of the car is to line up the splines to put the car (effectively) in gear. I haven't seen many modern cars with the dis-engage-able QC I guess they were a little complicated to fix/set up between races.
The photo shows a dragster with the slider coupling.

Scotty.

 

Yeah, back when the original Halibrand was still around they had a kit to convert a Q.C. in that manner.

 

Thanks to all you guys. I finally "get it". I am always impressed by the helpful and polite (!) assistance that posters on HAMB give. Not like some newsgroups where you get dirt kicked in your face for asking a simple question ;-) Cheers.

 

Simple questions we can answer, Stupid ones WILL get dirt kicked in your face. lol.

Scotty

 

just to confuse all of you between the "in and out box" years and the modern shifter rear ends there was a shifter drive line used that slid the driveshaft and coupler ahead and off the input shaft of the rear end.you will still run across a one piece lower shaft that has a bronze pilot bearing in the front end of it.

 

surprisingly the reason sprint cars went away from in and out boxes wasnt weight or reliability,it was to get a longer torque tube and drive shaft.on a torque tube car the point where the rear end torque pushes up on the chassis on acceleration is at the front of the tube.the farther ahead that is the better the weight transfer.