Exit gate with cow push bar for milking parlor
A push bar serves to nudge or urge cows to leave a milking parlor and move to an exit alley. The push bar is mounted on extendible support members, which may have an inner tube and an outer tube, and which is mounted by a journal onto an overhead pivot. There is one air cylinder to rotate the assembly, and additional air cylinders to extend and retract the support members. A programmed controller ensures that the push tube travels in a generally straight, horizontal path to push the cows out, and then lifts the push tube so it is over the cows' heads on the return.
1. An extendible and rotatable push bar assembly for gently urging cows out from a milking parlor after the end of a milking operation; comprising:
a horizontal push bar;
an overhead horizontal pivot member;
a plurality of extender slide assemblies, each having an upper slide member with a journal member that is pivotally journaled on said overhead horizontal pivot member and a lower slide member movable in said upper slide member, and supporting a respective end of said horizontal push bar such that the horizontal push bar moves radially in respect to said overhead horizontal pivot member; and each said slide assembly including a linear actuator that extends the lower and upper slide members relative to one another for controllably extending the push bar radially outward in respect to said pivot member; and
means independent of said linear actuator for controllably rotating the upper slide members about said pivot member to sweep the push bar controllably forward to urge the cows out of the milking parlor.
2. The push bar assembly of claim 1 wherein said extender slide assemblies each include an outer tube journaled to said overhead horizontal pivot member and an inner tube slidable in said outer tube and having a support at its lower end in which said push bar is supported.
3. The push bar assembly of claim 2 wherein said support at the lower end of the lower tube fits said push bar loosely to provide sufficient play so that the lower and upper tubes do not bind when the extender slide members are extended and retracted.
4. The push bar assembly of claim 1 wherein said push bar includes a push tube.
5. The push bar assembly of claim 1 wherein said means for rotating includes a pivot arm extending from said journal member and a linear actuator connected to a free end of said pivot arm.
6. The push bar assembly of claim 1 wherein said journal member includes a lubricated plastic sleeve.
7. The push bar assembly of claim 1 comprising a programmable control mechanism for controlling linear actuation of the extender slide members and the means for controllably rotating the upper slide members, such that the push bar travels in a straight and generally horizontal path to urge the cows out of the milking parlor.
8. The push bar assembly of claim 7 wherein said control mechanism controls said linear actuators and the means for controlling rotation such that the push bar is withdrawn radially towards said pivot member and is raised above said horizontal path to travel on an elevated return path.
9. The push bar assembly of claim 7 wherein said milking parlor defines cow milking positions in which cows stand with their hind ends at a hind end position, and said means for rotating the upper members is adapted to move said push bar from a position behind said hind end position to a position in advance of said hind end position to urge the cows out of the milking parlor.
10. The push bar assembly of claim 1 wherein said milking parlor defines cow milking positions in which cows stand with their hind ends at a hind end position, and said means for rotating the upper members is adapted to move said push bar from a position behind said hind end position to a position in advance of said hind end position to urge the cows out of the milking parlor.