It could be possibe it was turned off - look at the clock face esp to the right at about 3 -o'clock) there may be a lever which turns it on - off. Of course slide it to on positiion. Also look at 9 o'clock.
If there is none - then very gingerly and carefully slide your hand up the right side of the box part with the weights. There may be a very thin string which hangs down which your can feel if you reach your hand up toward the bonnet. If there is one then very gently pull it down and it should chhime if it had been turned off. The counterpart to turning it off is same place on the left side. If neither work to turn on the chimes then you should call an expert clock repairer. Good luck - let me know.
If you cant't feel the string, look up in there with a flashlight.
You could also slide the bonnet off and look to find the string.