Bridgeport Series 1 CNC part broken, need help ASAP

Ok so FYI I dont machine.....yet. But my husband has his whole life, his business run around his machines. Yesterday his BP 1 brpke a piece off. I have a pic(trying to figure how to upload it still.) I am trying to figure out what its called and where I can buy a replacement part. The machine is unusable without it. It looks almost like a cylinder with 4 rectangles cut out of it. It drops down when you put in a new tool and then pulls back up to secure the tool in place. This machine is OLD, it is an original series 1. Right now I just need help finding this part. I also have an email into Hardinge to try and get assistance from their parts department to, so far no reply.

http://s1146.photobucket.com/user/McGee2018/media/52730_zpsicyrvrea.jpeg.html

52730_zpsicyrvrea.jpeg Photo by McGee2018 | Photobucket

Here is a link to a picture if the part. Hopefully this works....it wasthe only way I could think to upload a pic on here.