Arrangement for interchangeably mounting different injection units on an injection molding machine

Claim 1

In an injection molding machine which comprises a die closing unit with a longitudinal center axis along which the unit executes opening and closing movements and which has, as a part of said unit, a stationary die carrier plate extending transversely to the center axis, a movable die carrier plate and two die closing unit tie rods which are parallel to and equidistant from the center axis, extending forwardly from the stationary die carrier plate, to serve as guides for the movable die carrier plate, the tie rods having their rear extremities rigidly clamped to the stationary die carrier plate by means of preloaded tie rod connections, in such a machine, an arrangement in association with said preloaded tie rod connections for selectively and interchangeably mounting to the rear side of the stationary die carrier plate several axially oriented injection units of varying size, each having a pair of injection unit tie rods, the spacing of which is either equal to, larger, or smaller than the spacing of the two tie rods of the die closing unit, the mounting arrangement comprising in combination: as part of said preloaded tie rod connections, two tie rod seating bores in the stationary die carrier plate, each seating bore having a fitted bore portion and, on the rear side of the plate, an enlarged recess bore portion forming an axially rearwardly oriented abutment shoulder around the fitted bore portion; also as part of said tie rod connections, a matching end portion on each of the two tie rods of the die closing unit having a fitted tie rod length portion engaging the fitted bore portion, an enlarged collar member to the rear of the fitted length portion received inside the enlarged recess bore portion so as to engage its abutment shoulder, and a rearwardly oriented tie rod end face; and two tie rod mounting sockets which are attachable to the forward extremities of the two tie rods of an injection unit, each mounting socket having an axially forwardly oriented clamping face which is clampable against the end face of one of the two die closing unit tie rods, thereby axially preloading its collar member against the abutment shoulder; and wherein each mounting socket further includes fastener means engaging the mounting socket and the rear side of the die carrier plate on several attachment points around the associated tie rod seating bore, for the creation of such a clamping preload; and the two mounting sockets further include means for positioning and centering the two tie rods of the injection unit at the required tie rod spacing.