a timing gear carried by {HEAD ~ said housing} and within {TAIL ~ said chamber} and having a predetermined number of teeth 
a timing gear carried by { HEAD ~ said housing } and within { TAIL ~ said chamber } and having a predetermined number of teeth
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH