Milking stall with indexing lift rail

A milking stall comprising:

• a lift rail;
• a support column attached to the lift rail, the support column configured to be pivotally connected to a lift system for raising and lowering the milking stalls;
• an actuator for rotating the lift rail between a neutral position and a maximum position, wherein the actuator comprising an inflatable/deflatable air cushion mounted on the support column and situated to abut the lift system when the milking stall is mounted on the lift system;
• at least one divider mounted on and extending transversely rearward of the lift rail;
• and,
• at least one exit gate mounted on and depending downwardly from the lift rail, the at least one exit gate comprising a head rail rotatably mounted on the lift rail and at least one shoulder bar connected to and depending downwardly from the head rail,
• the at least one exit gate pivoting with the lift rail between the neutral position and
• the maximum position, the at least one shoulder bar pointing more rearward in the maximum position than in the neutral position,
• the head rail rotatably mounted on the lift rail through at least one torsion spring mounted on the lift rail, the at least one torsion spring biasing rotation of the head rail independent of and relative to the lift rail, the torsion spring pre-loaded on the lift rail to provide a rotational bias to the head rail so that the at least one shoulder bar is urged rearward by the rotational bias.

A milking stall comprising:

• a lift rail;
• an actuator for rotating the lift rail between a neutral position and a maximum position;
• at least one divider mounted on and extending transversely rearward of the lift rail;
• and,
• at least one exit gate mounted on and depending downwardly from the lift rail, the at least one exit gate comprising a head rail rotatably mounted on the lift rail and at least one shoulder bar connected to and depending downwardly from the head rail,
• the at least one exit gate pivoting with the lift rail between the neutral position and the maximum position, the at least one shoulder bar pointing more rearward in the maximum position than in the neutral position,
• the head rail rotatably mounted on the lift rail through at least one torsion spring mounted on the lift rail, the at least one torsion spring biasing rotation of the head rail independent of and relative to the lift rail, the torsion spring pre-loaded on the lift rail to provide a rotational bias to the head rail so that the at least one shoulder bar is urged rearward by the rotational bias;
• wherein the torsion spring is an elastomer powered torsion spring comprising:
• a tensioner housing;
• an insert;
• and a plurality of elastomeric plugs, wherein
• the tensioner housing has the insert inserted therein,
• the tensioner housing and the insert have a same polygonal cross-sectional shape,
• the insert is rotated with respect to the tensioner housing to provide spaces between internal corners of the tensioner housing and outer faces of the insert, and
• the elastomeric plugs are friction fitted into the spaces.