Is there such a thing, or a specific term for "break before make" relay that can delay between breaking and making connection?
It sounds as though you are looking for a relay with "centre-off" contacts like an on-off-on, three-position toggle switch. If these exist they are very rare as most relays have only two states, on-off. To do what you are asking would require two coils in the one relay to pull the contacts either way from the centre position.
It's not clear why you think you need this arrangement.
simulate this circuit – Schematic created using CircuitLab
You can do the job with one DPDT (double-pole, double-throw) relay provided that you don't need it to stop in mid-position. Limit switches are required to cut power to the motor at the top and bottom of stroke.
How it works:
- With the relay in the position shown current flows to the motor through UP LIMIT and returns through DN LIMIT.
- When the projector is fully up UP LIMIT will be depressed and power to the motor is cut.
- When the relay is energised both contacts will be switched. Current will now flow through DN LIMIT, through the motor and return via D1.
- The motor will run until DN LIMIT is depress and will then stop.
- Meanwhile UP LIMIT will have closed again so when the relay is switched off the screen will run up again.
D1 and D2 neeed to be rated to handle the maximum current of the motor.
If you decide that a manual switch is all that is required then replace RLY1 with a DPDT switch.