Plastic article or earthenware shaping or treating: apparatus – With safety feature
Reexamination Certificate
1999-10-07
2001-11-13
Nguyen, Nam (Department: 1722)
Plastic article or earthenware shaping or treating: apparatus
With safety feature
C403S300000, C425S185000, C425S195000, C425S444000, C425S554000
Reexamination Certificate
active
06315544
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to extension bars for connecting a mold ejector plate to a press ejector plate in an injection molding apparatus and in particular to extension bars which are adjustable in length.
In a conventional molding apparatus, a molded part is produced by injecting mold material into a cavity formed between a stationary and a movable mold half mounted to a mold press. The stationary mold half is mounted on a front stationary platen of the mold press and the movable mold half is mounted to a movable platen which is generally slidably mounted on tie-rods extending from the front stationary platen to a rear stationary platen of the mold press. The movable platen is hydraulically advanced toward and away from the front stationary platen during a mold cycle to move the movable mold half between a closed and open alignment with the stationary mold half.
Mold material is injected into the mold cavity when the movable mold half is positioned in the closed position relative to the stationary mold half. Once the molded part has set, the movable mold half is separated from the stationary mold half, and the molded part is then ejected from between the two mold halves using an ejector assembly.
A typical ejector assembly comprises a plurality of ejector pins, which are connected to a mold ejector plate slidably mounted relative to the movable mold half. The mold ejector plate is connected to a press ejector plate by extension bars or tie in bars. The ejector pins are slidably mounted within the movable mold half in bores which open into the mold cavity. The ejector pins are advanceable between a retracted position within the bores to an extended position wherein a portion of each ejector pin extends into the mold cavity for ejecting the molded part out of the cavity.
The mold ejector plate is typically mounted within a chamber in the moveable mold half. The mold ejector plate is mounted in the chamber to permit it to slide toward and away from the mold cavity. The extension bars extend through aligned holes in the movable platen and a rear wall of the movable mold half and connect the mold ejector plate to the press ejector plate.
In ejecting the molded part from the mold, the movable platen is first advanced away from the front stationary platen to pull the movable mold half away from the stationary mold half. After the moveable mold half has separated from the stationary mold half and advanced to a fully open position, the press ejector plate is hydraulically advanced forward to advance the mold ejector plate forward relative to the moveable mold half and to advance the ejector pins from a retracted to an extended position thereby ejecting or separating the molded part from the moveable mold half.
The molded part then typically falls from between the stationary and moveable mold halves. The press ejector plate is then retracted hydraulically and the mold halves are advanced to a closed alignment and the cycle is repeated.
The stationary and moveable mold halves are removably securable to the mold press such that different molds may be interchangeably connected to the mold press to permit efficient utilization. In changing out a mold, the moveable mold half must be disconnected from the moveable platen and the extension bars must be disconnected from the mold ejector plate contained within the moveable mold half. The new moveable mold half must then be connected to the moveable platen and the extension bars must then be connected to the mold ejector plate.
The optimum length of the ejection stroke for the ejector pins will vary from mold to mold depending on differences in the size and shape of the part to be molded. In addition, the length of the extension bars may need to be adjusted during the life of the mold to accommodate wear to the mold. In existing systems, mold press operators typically use extension bars specifically machined to the desired length and must continuously machine extension bars to fit different molds and presses.
There remains a need for an extension bar or tie-in bar for connecting a mold ejector plate to a press ejector plate which is readily adjustable in length and adapted to expedite mold changes and set-up.
SUMMARY OF THE INVENTION
The present invention comprises an extension bar for connecting a mold ejector plate to a press ejector plate which is adjustable in length. The extension bar includes a rotatable member which is threadingly secured on one end of a threaded stud. An opposite end of the threaded stud is connected to the press ejector plate. The rotatable member includes a head and a shaft with a threaded bore extending into the shaft into which the threaded stud extends. The head of the rotatable member is connected to the mold ejector plate. Rotation of the rotatable member relative to the threaded stud increases or decreases the overall length of the extension bar.
A locking assembly comprising a locking sleeve biased by a spring into engagement with a locking nut is mounted on the extension bar to prevent adjustments in the length of the extension bar without first advancing the locking sleeve out of engagement with the locking nut. In particular, the locking sleeve is slidably mounted on the rotatable member shaft. A pin extending through the rotatable member shaft and aligned slots formed on opposite sides of the locking sleeve permits axial sliding of the sleeve relative to the rotatable member shaft but prevents the sleeve from rotating relative to the shaft. The spring is positioned on the rotatable member shaft between the rotatable member head and the sleeve to bias the sleeve toward the locking nut.
The locking nut is threadingly secured to the threaded stud between the locking sleeve and the press ejector plate. A plurality of bosses extend radially outward from a nipple formed on an end of the locking nut facing the locking sleeve. A plurality of notches are formed on the end of the locking sleeve facing the locking nut. The notches are sized to receive the bosses on the locking nut when the locking sleeve is biased against the locking nut. The bosses engage fingers on the sleeve extending between the notches to prevent rotation of the locking sleeve relative to the locking nut.
To adjust the length of the extension bar, the sleeve is slid away from the locking nut to advance the bosses on the locking nut out of the notches in the locking sleeve. The locking sleeve may then be rotated relative to the locking nut which causes rotation of the rotatable member relative to the threaded stud to adjust the length of the extension bar. The adjustability of the length of the extension bars facilitates changeouts of the molds connected to the mold press. The same extension bar can be used with different molds and the length of the extension bars can be adjusted to accommodate wear to the mold.
The extension bar is preferably connected to the mold ejector plate using a quick connect coupler assembly comprising a quick connect coupler and a quick connect stud. The quick connect stud is bolted to the mold ejector plate and the quick connect coupler is connected to the rotatable member head. The quick connect coupler is preferably of a type in which the quick connect coupler releases the quick connect stud by supplying pressurized air to the quick connect coupler. In a preferred embodiment, an airflow passageway extends through the extension bar for selectively supplying pressurized air to the quick connect coupler. The preferred quick connect coupler assembly permits the extension bar to be quickly and remotely secured to and disconnected from the mold ejector plate to facilitate changing out of molds from the mold press.
OBJECTS OF THE INVENTION
The objects of this invention include: providing an extension bar for connecting a press ejector plate to a mold ejector plate which is selectively adjustable in length; to provide such an extension bar which is readily connectable to a press ejector plate and a mold ejector plate; to provide such an extension bar adapted for use with a quick connect coupl
Brown Mark A.
Burger Philip M.
Burger Engineering, Inc.
Luk Emmanuel
Nguyen Nam
Shughart Thomson & Kilroy P.C.
LandOfFree
Adjustable length extension bars for connecting a mold... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Adjustable length extension bars for connecting a mold..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Adjustable length extension bars for connecting a mold... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2583374