Patent Application
20060083817
1. Field of the invention
The present invention relates to a toggle joint of an injection molding machine, more particularly one, which is equipped with leak prevention rings between a pivotal rod and bushings of a movable arm member thereof such that lubricating oil is prevented from leaking out.
2. Brief Description of the Prior Art
Injection molding machines are usually equipped with toggle joints, which are connected with both a stationary support disk and a movable mold seat so as to help displace the movable seat when an actuator is functioning.
Referring to
When an actuator functions to cause linear displacement of a movable mold seat (not shown) of the molding machine relative to a stationary mold seat (not shown), the movable arm member 62 will be angularly displaced. However, oil leakage from the toggle joint will happen after the molding machine is used for a certain period of time.
It is a main object of the present invention to provide an improvement on a toggle joint of an injection molding machine to overcome the above disadvantage.
The toggle joint of the present invention includes a stationary support disk, several spaced stationary arm members secured on the stationary support disk, a movable arm member, a pivotal rod, and bushings fitted in the movable arm member. Each of the bushings has oil passages on an inner side. The pivotal rod is connected to the stationary arm members and passed through the bushings such that the movable arm member pivots on the pivotal rod. Furthermore, each of the bushings has two annular grooves on the inner side, which are on two sides of the corresponding oil passages. And, leak-prevention rings are respectively fitted on the annular grooves of the bushings such that lubricating oil between the bushings and the pivotal rod is prevented from leaking out.
The present invention will be better understood by referring to the accompanying drawings, wherein:
Referring to FIGS. 1 to 3, a preferred embodiment (A) of a toggle joint of an injection molding machine includes a stationary support disk 1, stationary arm members 10, a first movable arm member 20, a pivotal rod 30, bushings 40, and leak-prevention rings 50.
The stationary support disk 1 is disposed on one end of a bed of the molding machine.
The stationary arm members 10 are spaced apart on the stationary support disk 1, and they are formed with aligned pivotal holes 101.
The first movable arm member 20 has several pivotal holes 201 at a first end, which are spaced apart and aligned with each other.
Each of the bushings 40 has two annular grooves 402 on an inner side, and oil passages 401 between the annular grooves 402 on the inner side. The bushings 40 are fitted in respective ones of the pivotal holes 201 of the first movable arm member 20.
The leak-prevention rings 50 are fitted on respective ones of the annular grooves 402 of the bushings 40.
The pivotal rod 30 has oil passages 301 therein, and it is passed through the pivotal holes 101 of the stationary arm members 10, and the bushings 40 in the first movable arm member 20. And, the pivotal rod 30 is connected to the stationary arm members 10 such that it can't be angularly displaced. Thus, the first movable arm member 20 and other movable arm members (not numbered) of the toggle joint will be angularly displaced when an actuator is functioning to cause linear displacement of a movable mold seat 2 of the molding machine relative to a stationary mold seat (not numbered). And, lubricating oil can be supplied between the bushings 40 and the pivotal rod 30 via the oil passages 301 in the pivotal rods 30 and the oil passages 401 on the inner sides of the bushings 40. Furthermore, the leak-prevention rings 50 will be closely fitted around the pivotal rod 30, preventing lubricating oil from leaking out of the toggle joint.
The leak-prevention rings 50, which are fitted on the annular grooves 402 of the bushings 40, can prevent lubricating oil from leaking out of the toggle joint of the present invention, overcoming the problem with leakage that exists in conventional toggle joints without proper leak-prevention means.
