I learned something new at the weekend, there's a good summary here:
Sprung v Unsprung Door Handles [for 'handles' read 'knobs']
Springs are required to get door handles to return to the horizontal after they have been pushed down. The spring can be located in the handles and or in the latch/lock. Most early handles were unsprung and most modern handles have springing.
You can tell if handles are sprung because they will return to the horizontal without being connected to the latch/lock. If you select unsprung handles then you need to make sure your lock/latch has a heavy duty spring, as this spring has to do all the work.
I had to replace three latches over the weekend which were either too stiff or too wobbly. Easy job, you might think, the old latches were standard size, buy three new ones and pop them in, refix the door knobs, sorted.
The first latch I replaced had old-style door knobs with no spring/return mechanism of their own (the latches have their own spring/return mechanism, so completely unnecessary). That was a ten minute job, line up the grub screws with a hole on the spindle, the new latch clicks into the existing strike plate nicely, job done.
Two of the three pairs of door knobs had their own spring/return mechanism, which were a bloody nightmare. It is nigh impossible to line up both knobs so their spring/return mechanism co-operates with the one in the latch, i.e. still very stiff to turn and you have to turn the knobs back again to get the latch to pop out.
Her Indoors complained that she still couldn't open the bedroom door without using both hands. She had a crack herself and after two or three hours she threw in the towel.
So I bought an unsprung pair from B&Q (the last one in stock), which works a treat and only needs the lightest touch to open and it clicks shut perfectly - provided you don't over-tighten the screws holding them in place (another twenty minutes of trial and error). If you over-tighten them, the mechanism jams or is it 'jambs' in this context?)
Which maniac decided to put springs in door handles/knobs? They are more expensive to make, a bugger to fit and don't work properly. What is the bloody point?