| 摘要 |
A piston head and rod assembly for use, for example, in a gear pump dry valve is disclosed. A cylindrical piston head is provided with a generally oval-shaped cavity formed therein which defines a minor diameter. The cavity opens through one end of the piston head. However, a portion of the opening is blocked by a radially inwardly-extending lip. The lip defines an opening diameter which is smaller than the minor diameter of the cavity. An end portion of a piston rod includes a reduced diameter neck portion and an enlarged diameter tail portion. The neck portion has an outer diameter which is slightly smaller than the opening diameter defined by the lip, while the tail portion has an outer diameter which is slightly smaller than the minor diameter defined by the cavity. To assemble, the tail portion of the piston rod is inserted through the portion of the opening of the piston head which is not blocked by the lip into the cavity. Next, the piston rod is moved relative to the piston head such that the neck portion is received within the opening diameter defined by the lip. Thus, the tail portion is retained within the cavity behind the lip for use. |
