In plastic blow molding equipment, the head tooling determines the diameter of the parison formed by such equipment. It is often necessary to change the head tooling to form parisons of a different diameter when it is desired to blow mold a product larger or smaller than the last object molded by such equipment. If the parison formed is too small, the walls of the object being blow molded are likely to be too thin, at least in places.
If the parison is too large for the product being formed, plastic material is wasted and a build-up of excess material due to such excessively large parisons can cause a malfunctioning of the equipment. Consequently, the head tooling must be changed from time to time to obtain the optimum sized parison for the particular product to be formed.
This changing of the head tooling is a time-consuming job, which is expensive, not only from a labor standpoint, but most importantly because the expensive equipment is shut down during such process. Such loss of productivity results in a loss of thousands of dollars of product. Consequently, there is a need for an apparatus which can reduce the time for changing head tooling to convert the parison being formed from one diameter to another.