Anti-twist Liner and Shell for a Dairy Animal Teat Cup Assembly

A teat cup assembly, comprising:

• a liner having:
• a mouthpiece defining a teat opening;
• a barrel joined to the mouthpiece, and defining a bore and a longitudinal axis aligned with the teat opening;
• a lower locking ring joined to a lower portion of the barrel and extending radially outwardly from the barrel;
• an upper locking ring joined to the lower portion of the barrel, extending radially outwardly from the barrel and spaced apart from the lower locking ring to define a shell-engaging annular recess, and the upper locking ring defines an alignment recess radially spaced apart from the longitudinal axis of the barrel;
• and
• a shell into which the shell liner is disposed, and the shell defines a lower opening with an inward annular edge disposed in the annular recess between the lower locking ring and the upper locking ring in the shell liner, and the shell includes a key disposed in the alignment recess.