What is it called?
This device is known in French as an “Écarteur de tétine de trayeuse”—best translated as a milking machine teat cup liner expander (also described as a liner flaring/rolling tool).
Where it was used
It belonged to dairy farming operations and was used during milking on the cow’s udders (the teats/trayons) to help fit the milking equipment correctly and safely.
Why it existed (the problem it solved)
In the early period of mechanical milking (“pots à traire” era), the rubber liner (manchon) that wrapped around the teat was not pre-molded. Because the liner was inserted into a stainless-steel tube, farmers needed to roll/flare the liner’s edge so it would sit properly on the tube and avoid hurting the udder.
Main purpose and function
- Primary function: Expand/roll (“rebouler”) the end of the rubber liner on the metal tube.
- Key benefit: Reduce the risk of pinching or injuring the cow’s udder while ensuring a secure, consistent fit.
- Practical advantage: It was faster and easier than using fingers, especially when done repeatedly.
How it was typically used (simple steps)
- Insert the rubber liner into the stainless tube of the teat cup assembly.
- Place the tool at the liner’s end.
- Operate the mechanism to flare/roll the liner edge into position.
- Confirm the edge is smooth so it won’t rub or cut the udder.
When it was common
- It was used before liners were factory pre-molded, meaning early-to-mid 20th century in many dairies that relied on older milking systems.
- The text specifically notes that after World War II, liners became pre-molded, reducing the need for this tool.
Why it disappeared
- Farmers had to do the rolling step often, because liners were removed after each milking to be cleaned in hot water.
- After WWII, manufacturers introduced pre-molded liners, so the rolling/expanding task was no longer necessary.
- As a result, these tools became obsolete and were often discarded or scrapped.
Quick identification features
- A wooden handle for grip and leverage
- A metal expanding/lever mechanism at the top
- A design meant to open/press/shape the liner edge consistently without damaging it